One Finite Planet

EV Charging Reference: Not just the new Refuelling.

First Published:

Table of Contents

This page covers a lot. Charging equipment and what to install and how to charge at home, and charging on road trips, through to the technical side, and a look at wireless and the future of charging. Plus, how recharging requires a complete rethink from refuelling, and how charging can be more convenient and match the speed of refueling.

Public recharging infrastructure for EVs is growing but recharging at home will be most important for most people. Fully benefiting from having an EV, requires understanding, being prepared for recharging.

Summary: (TL;DR).

While a little USA centric, this covers some key points.

An entire page about charging? Who would ever read this much about refuelling a gasoline car? Maybe in the early days they would, but this page is designed as a reference, with the ‘page contents’ set up to assist finding information needed at any given time.

The reference information of this page is mostly in the equipment, home charging, road trip charging and technical sections as well information on wireless, solar and other evolving areas. This page also provides background for those for that reference information, and the overall experience of charging. The key points of the overall experience are:

  • The big changes: Charging an EV is as more like charging a phone than like filling up with gas/petrol, why one reason it isnormal to charge at homeis why charing at home is th.
    • Unlike filling up with gas/petrol, if the answer to “what are you doing right now?“, is “I am charging my EV“, something is wrong as EV charging should happen in the background as with phone charging, which also doesn’t stop you from doing other things while charging.
  • Charging can be divided into three categories, with different prices and speeds:
    • Home charging is the least expensive, and most convenient option, and for most people, only requires access to a regular mains power socket.
      • For all but around the 14 days per year most people spend on ‘road trips‘, almost all charging can be home charging.
    • Destination charging‘: Charing away from home, while a at destination visited for another reason.
      • At overnight accommodation, restaurants, and shopping malls.
      • Sometimes even free, but generally mroe expensive than home charing.
      • Typically, with simple charging equipment and at low cost, but not as fast as rapid DC charging.
    • Rapid DC Charging as used while on a road trip.
      • While fast charging times, could become more like the experience at a traditional ‘gas station‘ in the future, today in 2021, fast charging typically takes at least 15 to 20 minutes if well planned, and up to an hour if not well planned or things go wrong.
      • The most expensive way to charge, typically 2x to 3x more, and reserved for when charging is least convenient.
      • Improving fast DC charging speed and availability depends on the rollout of charging infrastructure, and current infrastructure can be quite problematic.

Private vehicles normally spend of 90% of their time parked, and if they can be charged in the background during that time, the result is more convenient than even a 2-minute dedicated charging process.

Charging Electric Vehicles (EVs): Key Concepts.

A Shift in thinking that takes time to assimilate: two charging types, and not from near empty to fill.

Most of us have spent our entire lives in the world of the internal combustion engine vehicle. Many of us learn the principles of how these engine work, of concepts such as starter motors, alternators, radiators and the cooling systems, turbochargers, exhausts, clutches, multi-speed gearboxes and more. With EVs, all that familiar knowledge becomes must be replaced with ‘regen‘ and ‘AC vs DC charging‘ and other new concepts. It is a huge change, and it takes time to properly grasp new concepts.

The first big change is that, unlike refuelling an ICEV where there the experience at a roadhouse on a road trip feels similar to a refuel stop at a local ‘gas station’, recharging an EV includes two very different experiences:

  1. Foreground charging: Road trip style, more expensive, rushed, DC rapid charging, which should be avoided when possible.
  2. Background charging: Plugged in while parked at home or elsewhere is less expensive, and accounts for 95% of all EV charging.

Even though many people are unable to charge at home, JD Power reports over 80% of all EV charging is home charging.

A trap is “gas station thinking” and the assumption that because the rapid DC type of charging feels most similar to ICEV charging, that rapid DC charging will be the most common and most important way of charging.

Another key difference from refuelling ICEVs, is that the pattern of waiting until fuel is low, and then most often filling is not good practice with an EV. There are two good reasons to limit ‘filling the tank’ to times when full vehicle range will be needed:

  • When rapid DC charging, the charging becomes very slow on most batteries after either 80% or 85% and become far more time efficient to not wait until the battery is full.
  • When ‘background’ charging at home or other times without time pressure, it is usually still advisable to limit charge to around 90% as repeatedly completely charging the battery shortens battery life.

Also, rather than waiting until charging is needed, any time paring where charging is available, provided the price of charging is competitive, and there can even be times charging can be free, why not plugin or “graze”?

For almost all EV charging, charge times are not critical, because charging just happens in the background while the vehicle is parked, and the slow AC charging is used. It is usually only when DC fast charging, that speeds are important, because on the rare occasions DC charging is needed, it is needed because time is of the essence.

The reason for the emphasis given to rapid DC charging speeds, is because DC fast charging determines how fast it is possible to charge the EV. Fast DC charging determines charging capability. On the rare occasions when charging as fast as possible is required, DC rapid charging provides the charging.

For most people, a lifetime of experience has made everything relevant of living with internal combustion engine vehicles second nature. Logically, it could take years to gain the same level of comfort with the living with EVs, but given a little time, it will also become second nature.

It is possible to refuel instead of Recharging EVs, and refuelling Seems Faster, but maybe not better.

Many people start with the idea that recharging an EV is the direct equivalent of the refuelling they have experienced for years with internal combustion engine vehicles. To get the full rewards from owning an EV, a rethink is required. Refuelling vs recharging is like swapping the batteries on a torch vs recharging the batteries for a torch.

Refuelling is replacing the previously used, and now “spent”, fuel with new fuel that is already in a charged state. For an EV, is battery swapping. Just put in a new battery so the fuel supply is just like it was before the old battery was discharged. This is the true equivalent of filling up with gas. When you adjust to the difference, recharging is better, but until then, it can seem worse.

Recharging is adding energy to restore the “spent” fuel, back to its initial state. With fossil fuels, this requires huge areas of land to grow the plants that get the CO2 back from the air, and eventually use the energy from sunlight create oil underground from the same chemicals as are in car exhaust. But with batteries, we keep the “exhaust” inside the battery and can recharge in just hours, and amazingly, even do a fast recharge in just minutes!

In fact you can refuel some EVs, as battery swapping, previously championed but later rejected by Tesla, may be making a comeback. But with EVs, recharging is possible, and on most occasions, can provide a much better experience than the refuelling we are familiar with, even if there are situations where that more familiar, and faster, refuelling experience, may still be the best option. EVs enable a choice, and even if you feel refuelling (battery swapping) is how you would like to replace charge, it still makes sense to understand the alternative that most people prefer most of the time.

When asked about battery-swapping technology, Volkswagen spokesperson Mark Gillies told Car and Driver, Our data indicates that only 3 to 5 percent of all EV drivers use fast charging as an option to get juice in their battery.” In other words, most people are still charging at home at night for their daily driving.

Car and Driver: Aug 2020

Teslas were at one time all designed to accommodate battery swapping, but it was just not popular, as stated by Elon Musk:

It’s just, people don’t care about pack swap. The Superchargers are fast enough that if you’re driving from LA to San Francisco, and you start a trip at 9AM, by the time you get to, say, noon, you want to stop, and you want to stretch your legs, hit the restroom, grab a bite to eat, grab a coffee, and be on your way, and by that time, the car is charged and ready to go, and it’s free. So, it’s like, why would you do the pack swap? It doesn’t make much sense.

The Verge, 2015: Tesla sounds ready to pull the plug on promised battery-swap technology

‘Supercharging’ is no longer free for most people, but it logically will always be less expensive than battery swapping.

In China, some people are using battery swapping, but there are a lot of people in China. Different demographic, different time, different living and driving patterns, but most of all, a far larger sample of people in China drive EVs today than drove EVs in California in 2015. Taking VWs data of 3% to 5% of people using fast charging as the target market, then for one brand of EV in the Chinese market to have enough customers for a battery swapping service does not mean it will find enough customers everywhere.

The entire focus of battery swapping is mainly for road trips, and for when charging at home is not possible, but it is by nature a premium service.

Even those who make use of battery swapping (refuelling), normally recharge their battery at home or work when not on a road trip, and almost always prefer the lower cost and greater convenience of recharging when not on a “road trip”.

So, battery swapping exists, and could become more available, but it is hard to see widespread use happening, because if you own an EV, you are almost certainly going to find recharging more convenient and less expensive almost all the time.

The other problem for battery swapping is that by the time infrastructure is able to be rolled out, charging that is as fast as battery swapping could already be common.

Fuel Requires A Supply Chain, But Charge (Energy) Is Everywhere.

A first, it seems recharging a battery is the equivalent to refuelling a fossil fuel tank, but on reflection, refuelling is more like the equivalent to battery swapping. Recharging, which is using energy to restore chemicals back to their original state, is not practical with fossil fuels, partly because the ‘spent’ fuel or exhaust isn’t captured, but also because the processes for restoring it back to that original state is really slow.

Being able to recharge the fuel means you do not need the fuel ingredients, only energy. As electrical energy is far more ubiquitous, it allows an entirely different approach to “where does the energy to power my vehicle come from?”. Not only are there types of places to plug in such as at restaurants or supermarkets and shopping malls, but there are also options such as home solar.

Many problems can disrupt the supply of fossil fuel, but the very nature of the electric grid means long term disruption of electrical supply to a wide area is far less likely, and there are even off the grid solutions.

Like With Your Phone, Normal Life Means charging while parked, and mostly while sleeping.

Charging EVs fits somewhere between charging a mobile phone and refuelling an ICE vehicle.

Normally, as with a mobile phone, you charge at home, and while you are doing something else. The ideal way to charge is for the char to be plugged in overnight, while the driver is sleeping.

Also, most people don’t wait for the phone to signal that it needs charging, but instead top up the battery either overnight, or at other times they find it convenient to charge, but even though charging to 100% is not best for the phone battery, phone batteries far less expensive than EV batteries, and are rarely expected to last 10 years, so it is less important to limit charging.

Charging while sleeping, the ideal for an electric vehicle, will normally mean that overnight, vehicle is sufficiently recharged to replace at least whatever charge was used during the day, or at least ensuring more than sufficient charge for the entire next day. For most of us, this is just like what happens with a mobile phone.

Normally, the car battery will only need a top up each night, not a full charge, as how often would need to refuel an internal combustion vehicle on days you start with a full tank? The full tank used within a day! Generally, this only happens when on a road trip.

While there are many reasons for only wanting a refuel stop around once a week, there is little reason not to plus in after parking every night if it is possible.

For those where plugging in at night is not possible, EV ownership is way less satisfying.

Of course, just as some phones just don’t last all day if you watch lots of videos or some other battery intensive activity and could need an emergency top-up. Same with electric vehicles. While all early vehicles had terrible range, now even the least expensive EVs that sell for around US$5,000 in China can get at least 250km (150 miles). Given a normal person averages less than 60km per day (See charging systems reference), a range of even 250km should provide for even quite unusual days. Most days cars are used just for local transport, but for a road trip or for an ’emergency’ when the driver just didn’t get to recharge as they should, rapid charging at charging stations will be the solution until in road wireless charging is available.

Rushed/Fast/Rapid DC Charging: Last resort, best reserved for emergency charging and road trips.

A trap for people new to EVs, is that as DC fast charging best replicates the familiar fuel stop experience, and because DC charging is fastest, it can seem logical that DC charging is the ‘new way’ and has made AC charging somewhat obsolete.

Reality is somewhat different. The biggest negative of DC charging is that it requires expensive charging equipment, and a lot of electrical power. This creates two problems:

  • Unlike AC charging which can be available almost anywhere, Rapid DC charging requires a visit to one of the special locations equipped with the very high current electrical power, and the expensive charging equipment.
  • The need for the high current and special equipment, makes rapid DC charging normally significantly more expensive, and typically 2x to 3x the price of other charging options.

The goal with EV ownership, is to avoid needing to visit rapid DC chargers, and EV drivers manage to avoid them at the very least 80% of the time, with many owners going months between visits to a rapid DC charger.

Since most private vehicles spend 90% of time parked, there is normally lots of time to charge when parked. When rapid DC charging is needed, it is mostly still not as fast as ideal in those situations.

To travel long ‘road trip’ distances in one day, beyond the range of the EV being driven, rapid DC charging is the only solution, and at those times, who fast an EV can change becomes critical.

Car web sites and journalists do make a big thing of rapid DC charge times, but they also make a big point about 0-100km/h (0-60 mph) times too, and most people rarely do those sprints either. The times are important but does not mean that is how charging is normally done.

Rapid DC charging is normally only for road-trips. Just as you need to consider how you will charge your phone on a trip, you need a different arrangement when on a trip with your car. Now if you were watching videos all day on your phone on your trip, you may need to charge your phone more than once a day, and if you are going to be doing far more driving than normal on your trip, you will need to charge your car one a day. For both phone and car “rapid charging” become important.

Use of rapid charging should be very rare, unless a person either:

  • Has an unsuitable car.
  • Road test cars as an occupation, or has other commercial use.
  • Has free access to rapid charging or doesn’t have the ability to charge at home.

A car needing rapid charge, is in some ways like a person who did not get enough sleep last night, and as a result needs a ‘catnap’ to get through the day. Either the day is unusually tiring, or the person is not getting enough sleep. Frequent use of rapid or emergency charging creates problems because:

  • Rapid chargers are additional infrastructure that comes at a cost, increasing the cost of electricity.
  • Using a rapid charger frequently will reduce battery life.

For lowest running costs, best battery life, and the best experience from an EV, almost all charging should be at home and rapid chargers only used in exceptional circumstances.

Forget Full Recharge Time, Range Added Per Hour or Per Minute is what matters.

A common question is: “How long for a full charge?”, when in reality, EVs are almost never fully charged.

A far better question would be “how long to provide enough charge to drive 330 kms (or 200 miles)?

If an EV has a very small battery with terrible range, of course a full charge will be faster, but why? Consider which would you see as an improvement:

  • A new phone that charges 3x faster but needs to be charged several times per day, instead of one charge lasting all day.
  • A new phone that takes twice as long to fully charge but gets enough charge for a day in half the time and lasts a whole week, instead of one day, when fully charged.

An EV with a bigger battery may take longer to fully charge but will, typically, gain the same amount of range with less charging time. Charging an EV with a bigger battery for the same time as an EV with a smaller battery, will usually allow for driving further, even if the battery is not fully charged.

There are vehicles already available like the Lucid Air with 800km range, and vehicles such the Aptera with up to 1,600km range being released soon. Of course, there are also still EVs with very limited range. It makes no sense to compare time from empty to full of a vehicle with 1,000km or 1,600km of range, to the recharge time of a vehicle with just over 100km of range. So don’t be too focused only on time for a full charge.

What does matter, is how long it takes to add the range required fora given need. This can be stated as ‘range per hour’ for slow charging at home, because when ‘charging while sleeping’, it is easier to think in hours, but for rapid charging on the highway, it is better to think in ‘minutes to get range to reach the next stop’. In practice, there are two measures:

Only how long to add range matters, not %
  • Range per night or per hour, for ‘charging while sleeping’ for slow AC charging.
  • Time in minutes to add range for two or more hours of driving on the highway, for the road trip style high speed ‘rapid charging’.

Consider which would you rather have?

  1. A car with a small battery and a range of only 100km (60 miles), that fully charges in just 20 minutes, but have low range.
  2. A car with a large battery and a range of 800km that fully charges in 30 minutes, but will travel 400km from 10 or even 15 minutes of charging.

Surely option 2 is the better car to have, even though a full charge does take longer. As battery capacities continue to increase, the time for a full charge from ’empty’ to ‘full’ will become relevant even less often. What really matters, is how much range can be added in a given period of time, or how long will be needed to add the range required.

EVs are rarely fully charged anyway.

The goal is always charging to have enough range to comfortably reach the next planned or convenient recharging point. Then, it your going to stop anyway, recharge while stopped unless it is expensive.

All early EVs had so little range it made little sense to do anything but a full rechange, which is why “full recharge time” was at one time useful information.

While with ICE vehicles, it usually makes sense to use most of the fuel in the tank, and then ‘fill the tank’, this is not the normal pattern for every day use of an EV. However, with EVs, there are benefits to NOT fully charging:

  • When the battery is fully charged, regenerative braking is often limited, leading to increased wear on the brakes, and less economical driving until the battery has “room” for more energy.
  • The final 10-20% of charging, from 80% or 90% until 100% depending on the battery, take be far slower charging, and can even take longer than from 20% to 80% does on some cars. Waiting for that slowest part of charging is best one endured only if that last bit of range is really needed.
  • Continually keeping current chemistry batteries fully charger well documented to shorten battery life, and most cars have an option to allow regular charging to stop at around 10% less then fully charged. for this reason.

Picture yourself, 100km from you destination and needing sufficient charge to complete your journey. Would you think “I have a large battery that provides 800km range, so I must fill it and I wish I had a smaller battery that only provides 300km range!”.

Even on a road trip, when using ‘rapid’ charging, you need enough only charge to comfortably get to your next charge. Waiting until reaching 100% is usually wasting time if 80% would provide ample range to comfortably reach the next charging point, as beyond 80%, charging speeds will start to slow down.

Don’t wait until running low on charge.

With ICE vehicles, the trigger to refuel is most often the fuel gauge, or fuel level. While the level changes from person to person, most people normally fill or plan to fill when the gauge reaches a certain level. This is in large part due to the fact that refuelling is a dedicated gasoline stations or petrol stations. The process of refuelling may be fast, but the overall process takes time and has several steps. Which is in part whey most people fill the vehicle whenever they are going through all the steps.

With EVs, charging can be when parked at home, when at parked at the mall, or potentially, anytime when parked. In some of these locations, charging is even free! With all these places to charge where you were going to park anyway, why not charge every time the price is right. Even though the charging time itself takes longer, if the car is in the right place anyway, charge up!

Even on a road trip, given stops are generally recommended every 2 hrs, a stop will normally be before a recharge is essential, but provided there is a suitable place to have the stop while charging, this means all that is required is to replace the energy used in those last two hours. If, for example than means 200km to 260 km of range (120 miles to 150 miles) to be replaced, the charge time could be under 5 minutes, and still less than 20 minutes even with a relatively slow charging car.

Even if the vehicle does not need charging, connecting to charge can make sense for vehicle to grid or home, providing battery backup power. Further, if wireless charging (see below) becomes common, connecting up may become automatic.

In any event, the mentality of waiting until energy is slow before refuelling, as is normal with internal combustion engine vehicles, should be abandoned for the best experience with EVs. Plug in whenever the power is handy.

EVs Redefine ‘Road Trip Ready’.

There are two very different experiences when using a car to get people from a to b:

The links above provide further explanation, but think fetching groceries from the local supermarket as clearly a local trip, and a weekend getaway is usually clearly a road trip. Sometimes the lines get can be blurred, and travel will be a blend of both. What about a rare visit to a special farmers market 3 hours away? Or a weekend getaway in a location just 2 hours away? But mostly, travel can be categorised as fitting within one of the two categories, where once you need a rest stop on the way, it is a road trip.

The difference between the travel types mean vehicles can need different preparation. In fact, some vehicles are only suitable for ‘local’ trips. A vehicle can be still suitable for ‘local trips’, even though some of following limit use for ‘road trips’:

  • Questionable handling or safety: “I wouldn’t want to be driving that on the highway!”.
  • The tyres may need to replaced or suspension checked a car tackles a road trip.
  • If a service is due soon, it should happen before a lengthy road trip!

The point is, what is required of a vehicle changes between local trips and road trips. With an EV, the recharging changes too. With an internal combustion vehicle, the refuelling process stays exactly the same, even though the refuelling stops can feel different, as they are usually also driver breaks as well.

For local trips, charging is all about AC charging at home, maybe even having home solar, and having best power prices at home. It can also be about top up charging at shopping malls, and needing an type 2 charging cable.

For road trips, charging requires rapid DC charging and the use of a charging network. This can require membership to the charging networks, and typically cost more for electricity as the charging networks are an extra business in the chain, typically not earing income from recharging for local trips. Further, road trips with an EV usually involve working with software such as plugshare, or a better route planner, or an equivalent, or at the very least the cars own route planning software, in order to best plan stops.

The very first electric cars were totally unsuitable for road trips, and there are still some EVs that are unsuitable. Some EVs now are in some ways more capable of road trips than ICEV ever were, but road trip capability requires additional features.

A trip requiring recharging while on the trip, becomes clearly a ‘road trip’, that is different in nature from local trips EV.

Rethink Step: A reverse Perspective.

One way to picture how different owning an electric vehicle would be, is to consider what it would be like coming from an electric vehicle to an internal combustion car.

An EV owner has provided an answer in an insightful article looking from the other side. What would be required as a rethink for a person accustomed to electric vehicles, replacing their electric vehicle with a gasoline/petrol vehicle?

  1. I have heard that petrol cars can not refuel at home while you sleep? How often do you have to refill elsewhere? Is this several times a year? Will there be a solution for refuelling at home?
  2. Which parts will I need service on and how often? The car salesman mentioned a box with gears in it. What is this and will I receive a warning with an indicator when I need to change gear?
  3. Can I accelerate and brake with one pedal as I do today with my electric car?
  4. Do I get fuel back when I slow down or drive downhill? I assume so, but need to ask to be sure.
  5. The car I test drove seemed to have a delay from the time I pressed the accelerator pedal until it began to accelerate. Is that normal in petrol cars?
  6. We currently pay about 1.2p per mile to drive our electric car. I have heard that petrol can cost up to 10 times as much so I reckon we will lose some money in the beginning. We drive about 20,000 miles a year. Let’s hope more people will start using petrol so prices go down.
  7. Is it true that petrol is flammable? Should I empty the tank and store the petrol somewhere else while the car is in the garage?
  8. Is there an automatic system to prevent gasoline from catching fire or exploding in an accident. What does this cost?
  9. I understand that the main ingredient in petrol is oil. Is it true that the extraction and refining of oil causes environmental problems as well as conflicts and major wars that over the last 100 years have cost millions of lives? Is there a solution to these problems?

For this page, #1 is the most relevant, and conveys the important concept that “recharging while sleeping” is the normal, and going to a charging station should be an exception that only happens a few times a year.

EV Charging Equipment.

Two Types of Charging Equipment: AC for Home/Urban Vs DC Road Trip Charging.

Fuel consumption data is divided into ‘urban cycle’, and ‘highway cycle’ because there are two different types of driving. With fossil fuel vehicles, the refuelling is not very different for these two driving types, but with EVs, the recharging is very different.

With gasoline / petrol vehicles, the difference is that when refueling on a road trip, the stop will usually also include a refreshment stop for the driver and passengers, maybe a light meal or some fast food, while when refueling during urban driving, everyone but the driver may just remain in the vehicle the entire time. While the stop may be different, the refuelling equipment remains the same. With EVs, these stops become much more different, and even the recharging equipment and price paid to charge be different.

When it comes to the practical side, the sections on ‘home’ and ‘destination charging’ discuss the typical AC charging experiences, when the section on ‘road trip’ charging discussed the typical DC charging experiences. The equipment for these experiences, which somewhat correlate to the urban vs highway cycles and refueling for ICE vehicles are:

  • local trips on the urban cycle: mostly slower AC charging in the background while you do something else.
  • road trips on the highway cycle: ultra-fast rapid DC charging, as fast as possible because otherwise you will be waiting.

It may feel having more than one way to refuel is a weird new world, and by only bothering with fast charging, life with an EV will be simpler, and the world will remain similar the familiar world of internal combustion vehicles. Such thinking would be big mistake, as it is the slower DC charging that unlocks most of the benefits of owning an EV, the faster DC charging is the downside of owning an EV.

From another perspective:

  • Slower AC charging takes virtually none of your time, as it happens while you are doing something else.
  • Rapid DC charging still takes a problematic amount of time, often means time wasted time waiting for charging, and usually costs more substantially.

In the end, you do need both, but provided home charging is possible, there may be months and months where home charging, using simple inexpensive equipment, which may even come with the EV.

The Three Charging Levels, and the equipment.

Why 3 levels of charging, and now even 4 “charging modes”? (The IEC 61851 Standard).

Refuelling an internal combustion engine vehicle is not necessarily convenient, but it is always fast, and when refuelling an ICEV it is the main thing you are doing at that moment. Recharging can happen while you do something else, and at places where you were going to be even if not charging: At home while you sleep, at the mall while you shop, or at a restaurant while you dine. Recharging can be in the background while you do something else.

While for charging an electric car, you should normally avoid ‘fast’ most of the time, as rapid DC charging is more expensive, less convenient, but there are times when it is essential. This means it becomes necessary to use both AC and DC charging in order to cover all use scenarios.

But what about all the charging modes and charging levels?

In the end, there is really one AC charging and DC charging, and the modes and levels only refer to the mount of AC current available when AC charging. Other than AC or DC, the levels and modes don’t change either the process of charging, nor the basics of the equipment used when charing.

AC charging equipment all consist of both electrical cable and a control box, which only switches the AC power on when charging, and off when not charging or a fault is detected, and signals to the vehicle how much power is available. That is all the equipment does, and AC power goes unchanged straight to the vehicle, to be turned into the exact right DC power needed for charging by the on-board charger of the vehicle.

DC charging equipment takes the AC power from the grid, and rapid DC chargers need a special high current grid connection or their own battery supply and converts the power into the form the vehicle signals that it needs. DC charging equipment does process the power and is far more complex and expensive.

There are several articles on the charging levels already available, but such articles are often a little misleading, and some are sponsored by people selling ‘home chargers’ with a motive to upsell charging equipment.

Initially, with early EVs, a faster way of charging than a standard power point was introduced, giving rise to two “levels” of charging. Then, fast DC charging was introduced, providing a third “level”, even though it was never officially labelled a third level. Then the IEC 61851 standard was introduced, defining 4 modes, with level 1 split into the bad way (mode 1) and the good way (mode 2). Level 2 and DC charging became mode 3 and 4 respectively, and more clearly defined.

It is important to consider that wireless charging is real, just becoming available, and will become more important over time. Wireless charging is perhaps a fourth level, or 5th mode?

Level 1 the bad way (Mode 1): Banned in most countries.

Basic cable only.

This is simply directly connecting the domestic wall socket to the AC pins on the charging socket of the car.

There are two problems here:

  • There is no information to the car on how much power is safely available.
  • The entire power cable, much of which will be on the ground next to the car, will be ‘live’ unless the whole time the car remains connected, unless someone manually switches off the power when charging is complete.

Most developed countries do not allow this system, and cars are configured to not charge unless the supply can send control signals and identify there is a controller somewhere.

Level 1 Charging (Mode 2), Mains power: Solution for charging in the background while sleeping.

Level 1/ Mode 2

Level 1 / Mode 2 charging is still charging a car from a standard home mains power socket but adds an intelligent controller box inline in the cable, which makes a safer solution.

The controller box has two functions:

  • Inform the car of the current it is safe draw.
  • Switch off the power at the control box when the car is not charging, or there is a fault or safety risk.

When the control box has the power to the car ‘on’, that power is unchanged from the power at the wall socket.

For most people, this is all you need when charging at home.

Level 1 / Mode 2 charging will typically add around 4 to 7 miles per hour of range using USA/Canada/Mexico/Japan style 120v power, or 8 to 15 km per hour (5 to 10 miles per hour) in the rest of the world where mains power is 240v.

How fast? It depends on the national power. All cars can support the fastest possible level 1 charging:

  • 1.8 kW in the North America, Japan and other 110v-120v countries (115v 16Amps).
  • 2.4 kW from 10A ‘world’ sockets outside (North America and Japan).
  • 3.6 kW for 15A ‘world’ sockets (outside North America and Japan)
Also called a ‘granny’ cable.

Those were the fastest level 1 rates, what about the basic level 1 rates from standard sockets:

  • 1.5 kW in the North America, Japan and other 110v-120v countries.
    • 15A maximum, allow for 10% charging losses.
    • 5 miles range added per hour for typical car size EV
  • 1.8 kW from 10A sockets outside North America and Japan.
    • using 8 Amps for safety and 10% charging losses

Level 1 is for charging in the background while you are at home. Level 1 is too slow for background charging while at places where you spend less time, such as the mall or a restaurant, or even the office. And it is nothing beyond an emergency solution when on road trips, as during a road trip you are normally away from home, and typically driving both further and faster. Home charging is about ‘recharging while sleeping’ after a typical day driving. Most people only need to be able to add less than 80km or 50 miles of range each night.

There is a myth that charging from standard mains socket is always too slow to be useful. In reality, it is all most EV owners ever need. See this quote from ‘fully charged‘:

For the occasional long-distance electric car journey, now I say occasional because most people don’t drive 350 miles in a day, regardless of how many times I get told that on twitter, statistically, it’s inaccurate. It’s about 25-30 miles a day is the average car journey, not only in the UK but in every European country and North America. In North America that is the average and yet you could drive 3,000 miles across the United States, which people have done, and people do regularly, but not that often.

Robert Llewellyn from Fully Charged.

While a full charge from empty using level 1 could take over one full day, how often will you arrive home with a completely flat battery, and also require a fully charged battery again at the start of the next day, as opposed to the at the very least over 100km range that would be added overnight? As discussed in the section on home charging below, for most people such a situation would happen so rarely, that visiting a rapid charging station first rather than arriving home empty, or some other easy solution, would not be a problem if that situation ever did occur.

This means Level 1 charging from a standard mains socket is sufficient for most people, most of the time for home charging, provided they leave their car connected and can charge while sleeping. However, those owning an inefficient vehicle with a long commute in a 110v country, or those sharing the charging point between several vehicles, the next step may be required.

Use of level 1/Mode 2 charging beyond charging at home, is best considered only as a fallback for when nothing else is available.

Level 2 (Mode 3): Faster charging, when three is less time, but charging is still happening while doing something else.

Level 2 / Mode 3

If you take the control box that was in the cable with level 1 / Mode 2 cable, and mount it on the wall, or in its own stand-alone cabinet, then you almost have Level 2 / Mode 3 charging.

Only almost, because level 2 / mode 3 is when there is increased power available over and above that from a standard power socket. This charging allows for 7kW or more, which although possible with level 1 charging, with special high-power sockets, but when charging at 7kW or more, level 2 charging with a wall mounted control box is preferred.

For the best provision of power, these control units are directly wired to the home or other circuits, but they can also be plugged into high-power mains sockets where these are available. Given the potential for higher power, there are also usually further protection circuits, or at the very least, higher rated protection circuits.

Being equivalent to several household power points provides a step up from the previous level 1 / mode 2, where charging has only the power of a single home power point. This also makes using this mode of charging preferrable for in the background while at work, or the mall or supermarket or dining, at other locations, where the length of time parked will normally be less than is possible at home. Plus, the ability to provide a full charge from empty overnight, makes this mode very useful for an overnight stay during a road trip.

How much faster is level 2? It varies. The speed is limited by charging technology within the car. For a more detailed explanation of AC charging power sources see ‘AC Charging Currents‘ below, but in overview:

  • All cars can support at least 7kW (around 3x level 1 speed)
  • Most cars including Teslas and similar priced cars, support 12kW (around 6x level 1 speed).
  • Some luxury cars when in 3 phase outside of North America, Japan etc, can support 22kW. (10x level 1 speed)
Wall box
Freestanding

Some ‘wall box’ units can be plugged in, typically to a specialised high-power socket with more power than regular home sockets. In the US or 120v countries, such sockets may be available for laundry appliances, and in 240v countries, 3 phase power sockets may be used. However, wiring the unit directly to the power source and avoiding any socket is best.

Box wall boxes and freestanding units are ideally directly connected to main power without any plug and socket between them and the point of supply, as this eliminates any constraints of such sockets, and allows for the higher power rating.

Level 2 / Mode 3 charging provides for high-speed AC mains power charging, from either a wall mounted unit, or free-standing supply equipment unit, and incorporates either a built-in charging cable, or one of the EV specific AC charging sockets, as listed here, such as CCS1 or CCS2.

Wall box units are typically for home use, while applications for stand alone units range from company car parks, shopping malls and super markets, to charging at overnight accommodation or other public venues.

For home charging, stepping up to Level 2 / Mode 3 can offer more convenient charging, faster charging, or both.

Generally, level 2 charging is most appropriate for charging in the background while you do are doing something else. You don’t normally visit to a level 2 charger to get charge, instead you visit that location for another reason, and use the charger while you are there.

Outside the home, main locations that may offer Level 2 charging include:

  • Shopping malls.
  • Supermarkets.
  • Office carparks.
  • Commercial carparks.
  • Overnight accommodation.
  • Hotels and event venues.
  • Restaurants.
  • Depots for delivery vehicles.

While Level 1 charging can charge overnight after a ‘normal days’ driving, Level 2 charging provides for fully charging vehicles such as travellers that may arrive with an empty battery and need a full charge for tomorrows drive.

In general level 2 charging will normally be focused on provide a useful amount of charge, in the time period visitors will be at the venue.

Level 2 car charging can be limited to 7kw, 12kw or sometimes as high as 22kW or even 40kW.

Level 2 chargers also have different capabilities, and often are more often only 7kW in 100v countries, and up to 22kW in 240v three phase countries.

For home charging Level 2 / Mode 3 chargers may be used even for only providing similar power levels to Level 1 charging, because a wall box is tidier than an inline control box and can provide convenient access and storage for charging cable. So, a wall box can provide benefits beyond faster charging.

This site quotes range/distance added per hour as: 3.7kW= 20km, 7kW=40km and 22kW=120km, which should be indicative, and should be conservative for urban charging, but definitely less so for a stop during a road trip if travelling at highways speeds.

Level “3”(mode 4)/DC: Rapid Charge for road trips, and emulation of gas/petrol/diesel refuelling.

Level 3 / Mode 4

Though not officially called Level 3, the next level of charging is ‘DC rapid charging’, and is the system specifically designed for charging electric vehicles. While Level 1 and 2 are designed around sending the AC power that already exists in national electric grids through to a car, DC charging is all about the provision of electric power supply equipment designed for the needs of charging electric vehicles.

Rapid charging is needed when ‘charging while sleeping’ isn’t practical. Ideally, EVs would have sufficient range to deliver whatever is required even if driving all day, and thus always able to be charged after the day is over. Reality is, there will always be times when a way extending a vehicles range is required, although in future this may be through road based wireless charging.

The goal of rapid charging is the highest possible transfer of power possible into the vehicle, and this means the greatest stress on all electrical systems. Rapid charging should not be needed often, but when it is needed, you tend to want it as fast as possible.

AC/DC?

Charging quickly requires high voltages and currents. Normally in homes, we think of AC as high power and DC as low power as there is high voltage mains AC, and plug packs produce low voltage DC. AC is a great way to send power over long distances, and was great around the home 100 years ago, but now less and less equipment directly uses AC. Most equipment now first converts AC power into DC, and cars are no exception. All batteries, including EV batteries are always DC, and are always charged with DC power.

The DC power used to charge EVs, is charging using hundreds of volts, supplied at the exact appropriate voltage required at and given time, and this type of power is only available at high-speed chargers. This DC is nothing like the lower voltage DC associated with batteries in flashlights at home!

Charging an EV battery, requires applying the optimum high voltage DC power battery for the current state of charge of the battery. There are two ways cars source the exact voltage needed at each point during charging:

  1. The cars’ own internal DC voltage generator, which can convert a range of AC voltages into the DV voltage as required during charging.
  2. External high voltage DC supply equipment, that will supply the exact DC voltage the car determines it requires at any time.

This means cars can flexibly charge from domestic AC power to provide charging withing the power limits of their internal circuitry. These circuits can handle beyond the maximum possible from normal household sockets and can handle typically power from special high-power outlets, of up to either 7, 11 or 22kW depending on the vehicle.

AC power is normally the lowest cost source of charging current, and therefore is the preferred solution when there is plenty of time to charge, such as at home over night.

When faster charging is needed, specialised DC power supply equipment is the solution.

As a general guide:

  • AC: charging at home or lower speed charging, or charging smaller batteries such as those of PHEV.
  • DC: Newer, specialist rapid charging currently capable of delivering 350 kw.

Solar Chargers.

There is also equipment to either charge cars directly from solar power as discussed below, or to manage home solar to optimally use solar to charge vehicles at home.

There is also a separate page on solar vehicles.

The Change: From Gas/Petrol/Diesel Refuelling vs EV Charging.

Recharge where you park changes the experience.

The only place you can refuel a petrol or diesel vehicle, is at a ‘gas station’ (or ‘petrol station’ for those outside the US). A specialist location for refuelling. The entire gas station is the equipment for refuelling, while charging is possible as any parking space.

Having made a trip to a gas station, financial constraints aside, you may as well fill the tank, as it won’t take much longer half fill the tank, or completely fill the tank, unless the vehicle is very large.

Internal Combustion Engine Vehicle (ICE)Electric Vehicle (EV)
Road Trip Important SpecificationDistance Between RefuellingTime To Add Range at Fast Charger
Normal Use Important SpecificationDays Between RefuellingRanged Added Overnight
How To Refuel/RechargeSpecial Stop at gas stationNormally just park at home.
On Road trips at charging station.

What the?? Different Types of Refuelling/Recharging?

Whether on a road trip, or just filling up for commuting, the refuelling experience with an ICE vehicle is basically the same. However, with an EV, the experience on a road trip changes completely from charge while you park, to park just to charge.

  • Urban use: charge while you park.
    • Parked anyway, charging just happens in the background, no time lost.
  • Road trip: park just to charge.
    • The charge is needed, unless you need to eat or rest, time lost waiting for charge can add up!

A Surprisingly Very Different Experience.

Before concluding what range is needed to end range anxiety with EVs, it is worth considering the role refuelling plays the range we need.

Part of the reason our current vehicles need the range we are now expect, is that refuelling with gasoline or diesel, is not something we want to do every day. It doesn’t just happen when we park, it requires a special stop. Most of us will not visit a gas/service station until the tank is less than half full. But with an EV, sometimes there are parking spots we can only use if we charge, and other times the charge is right there if we want.

In normal day to day living, the range of our vehicle determines how often we have to refuel. Refuelling takes time out of our day. There can be queues and we can do nothing else while we refuel. Fuel is also dangerous, and has fumes that are also dangerous, and this determines the character of the refuelling point, and why we are required to pay attention to what we are doing.

The National Fire Protection Association requires that they’re put up as a precaution. Phones do cause static electricity and just because it hasn’t happened yet, that doesn’t mean it never could. Their rules also state that you’re not allowed to use electronic materials at gas pumps, and cell phones fall into that category. The NFPA advises that you always follow all rules posted at gas stations and consult your phone’s owner manual for information on proper use.
The primary reason you shouldn’t use your phone at the pump (besides the fact that there are signs telling you not to) is that it’s a major distraction.

Why You Need to Stop Using Your Phone When Pumping Gas

Now consider electric refuelling. All that is required is a power point. Refuelling can be at the office, at home, or even at the supermarket. You don’t need to pay attention, and you won’t toxic chemicals on your hands or clothes. The worst way to refuel an electric vehicle, is to follow the old behaviour, and go to a location specifically to refuel and have nothing else to do while refuelling. Refuelling EVs can be no more inconvenient then using the right parking space, and is definitely best not done in the old way, as a special place just for refuelling.

This really impacts needed for those who can charge at home or the office. A change in thinking from “I refuel when the time comes” to “whenever I park here I ‘connect’ the car”. Then, every day their vehicle has the full range, in place of a potentially half empty tank, where the half already consumed has saved the driver the need to refuel during the past few days.

In normal use, a major role of the ‘range’ of a gasoline/petrol or diesel vehicle, is saving you from having to refuel everyday. That aspect of ‘range’ no longer applies to anyone with some form of permanent, or electrified parking space.

Australian Input To An Answer “Can I Charge In Remote Locations?”.

Consider the following:

  • Australia is the least densely populated country amongst populous countries, with 3 people per sq km2.
  • A higher percentage of Australians live in urban areas than with other large counties, making the non-urban areas even more sparely populated.
  • Australia has one of the lowest rates of EV adoption of any developed country. (2.4% compared to 4% for USA., 5.5% for NZ, 18.3% for France etc at the time of this update in 2022).

The combination of these factors means is the distances between charging infrastructure will be quite extreme, and that if a range is adequate for an EV in Australia, that range is going to workable in any country. But then, Alaska for example, at 1.3 per sq mile or 0.5 per km2, has a lower population density than the Australian average. So, take it further, take the “state” of Australia, (or technically “territory) of the Northern Territory, with a population density of 0.16 people per sq km2, and at the time of this report, and only 61 registered EVs in total, being only 0.03% of vehicles.

Even in the Northern Territory, the report is that a P100 Tesla Model X, normally charged only to 90%, has fully adequate range for driving without problems in the Northern Territory.

Peace of mind for Mr Smith and his family comes from knowing that his vehicle charges overnight at his home, “just like a mobile phone”, powered from solar power collected during the day, and that — when he leaves in the morning for work or to drop off the children at sport — his car is ready to go.

ABC, Dec 2021: Sales of electric vehicles expected to surge in the NT in 2022

“I often hear people say that you can’t drive an electric vehicle in the NT, and I use that opportunity to let them know that it’s pretty easy actually … I let them know some of the things that I’ve done,” says Mr Smith, who is from Darwin.

Driving the Tesla, Mr Smith circumnavigated Australia over 18 days, often exceeding 1,000 km in a single day.

“I did Port Augusta to Melbourne in a day, well over 1,000 km, and Sydney to Brisbane in a day,” he says.

Mr Smith has also travelled extensively in the Northern Territory, including doing the Alice Springs-to-Darwin drive many times.

“It would be right to say that better and faster infrastructure along the Stuart Highway would make the journey easier, but there are many more electrical outlets in Australia than petrol stations, so in terms of being able to charge your vehicle there’s no problem,” he says.

ABC, Dec 2021: Sales of electric vehicles expected to surge in the NT in 2022

What is not revealed is how many minutes per 1,000 kms are required for the recharging, but the implication is that charging is not always fast, but can be found almost anywhere.

‘Home’ Recharging: Charge for ‘Local’/’Urban’ Transport.

What is home charging?

Home (or at work) Charging is at between 80% and at least 98% of all EV charging.

For most people, home charging is literally charging while at home. This literally at home charging, accounts for at 80% of EV charging. Allowing for the fact that data in the US has been skewed by early Tesla owners who have free charging on public Tesla charges, and far less than 80% of people are able to charge at home, would probably increase the percentage of people who would charge at home if not for exceptional circumstances.

Additionally, there are also those who park and charge their car at a regular location while at work, which can become another form of ‘home’ charging. In general, home charging is habitually parking and charging a location with charging for long enough, during a normal week when the driver is based at home to gain sufficient charge for a normal week.

Another way to think of it, is home charging is the charging done in places the vehicle has a guaranteed place to park and would regularly be parked even if not charging.

This report on charging habits in the US, surveying only vehicles with very limited range (like older Nissan Leafs), found 98% of charging events were performed at home and work on workdays.

For most electric car owners, overnight “charging while sleeping” is so normal, that there may be months and months between visits to public charging station. Visits to a ‘destination’ public charging station can require less attention than refuelling in ICE vehicle and can be available at convenient locations, but even the best public charging experience is less relaxed than just plugging when parking in at home.

Just plug in when you get home, and unplug before leaving, which will normally be the next morning. It doesn’t matter that you did not need to be plugged in the entire time. In fact, with wireless home charging, there are already some cars even plugging in is not needed and charging just happens whenever parked within selected times.

Home Charging Replaces Periodic Visits to gas stations.

With an ICE vehicle, around once or week or so for most people, a stop off for a refuel is required. These refuel stops are more mundane that the refuel stops on a road trip, and almost never involve a bathroom break or a meal. Some people sometimes grab a quick snack or emergency groceries. It is most common to fill the tank. While it is not universal to fill the tank, the visit was for the purpose of getting fuel, so unless the price is high at the time, or there is another issue, it is normal to keep filling until the tank is full.

Charing at home is a very different mentality. Unlike when on a visit to gas station, when at home, charging is not the reason you are at home, but rather, charging is something that can happen in the background while you are at home. With adequate home charging, the car will normally be fully charged every morning. In fact, normally, much of the time the car is connected at home, it will just be plugged in but not charging. Charing may be waiting until later to start when electricity prices are lower, or charging may have already finished. The car may even be plugged-in to allow the car to provide backup power in the event of a blackout.

If you have home charging, then charging is something that happens in the background while you are at home.

While some people find Level 2/Mode 3 home charging preferable, or even needed, most private cars spend sufficient time at home that even Level 1/Mode 2 charging will ensure that other than when on road trips, there is no need for charging elsewhere.

Home Charging Typically Only Needs to Add 60 km or 37 miles Of Range Per Day.

The average US motorist travels 13,500 miles or 22,000km which, divided by 365 days gives an average of 37 miles or 60 km per day.

The figure is 13,300 km per year or 36 km per day in Australia, and 10,880km (6,800 miles) per year or 30km per day in the UK.

In reality, those miles by average US motorist will normally include some long mileage road trip days, where there will need to be charging away from home, and the average distance travelled when at home will be a little lower. This makes the 60km (37 miles) an overestimate, and for those outside the US where annual distance driven are normally lower, a significant overestimate.

Deeper look at the impact on the grid.

But using the 60km/37 miles number as an average, if you can add 37 miles or 60 km each day range by charging at home, then you would never need to charge elsewhere, other than on “road trips days”, when you may travel further than the vehicle full range and will need to charge away from home anyway. For a car with 250 miles or 400km of range, a road trip day may mean a day with around 4 or more hours of just driving, which is not a normal day at home for most people.

All of this means that most people can do all their charging at home, “recharging while sleeping”, with the exception of vacations other long road trips.

Determining Charge Equipment Required for Home Charging.

Ability to FULLY charge every night is overkill, unless you drive the full vehicle range every day.

One of the biggest misconceptions of people new to EVs, is the assumption that an EV will normally be fully charged from empty to full. A full charge almost never happens, including when charging at home overnight. Misconception.

What is needed from home charging, is the ability to overnight add range beyond the needs of typical day.

If it was true that the amount to charge needed was determined by the power required to fully charge the battery, the solution would be to buy an EV with a small battery, as a small battery will take less time to fully charge at home. However, small batteries provide only limited range even when they are fully charged. The charging speed capability required is determined by how far a person drives on a typical day, not the size of the battery.

As long as more range can be added overnight than is needed for typical day, each day can normally start with a full battery.

There does need to be enough charging capability to also deal with a sequence of atypical days with longer drives. There are calculations below on how much charging capability is needed to provide home charging able to cover successive days of atypical longer drives. Home charging cannot ensure there will never be a trip to a fast DC charger, but it can make any need for using DC fast chargers when based at home extremely rare.

If you can plug in every night, charging will not normally start from empty. Only on a day where you arrive home having used almost the exact full range of the EV, would charging that evening start from empty. Even then, only if the next day will again be atypical and require more range added overnight, would a visit to a DC rapid charger be required.

To illustrate by example, for a typical EV, this means only if there would be two consecutive days of driving over 300 km (186 miles), while based at home, would a home charger that can achieve a full charge overnight, be fully utilised. If that rare event did happen while relying on slower home charger, the downside would be visit to a DC charger on the second day. Even with an ICE vehicle, with two consecutive days like that, you are going to need a gas station on the second day and will be paying far more.

Yes, home charging capable of fully charging a Lucid Air with 800 km (500 miles) of range in a few hours is readily available, and if you can afford a Lucid Air, then why not just buy that capability even if you never need it?

However, that rate of charge to fully charge a Lucid Air, which would be needed by people who drive 800km x 365= 292,000 kms or 182,000 miles) every year, would be a complete waste for most people. If you did somehow manage to drive that much distance, you will use a lot of power.

If we had a way of topping up the fuel tank of an ICEV every night at home, then we would never need a full tank of gasoline/petrol when at home either. Because we can’t conveniently refuel at home every night, and as a trip to the gas station each day would be inconvenient, we have a mindset of ‘wait until we need more fuel, then fill up‘. That long established behaviour no longer makes sense when owning an EV and able to charge at home, and there is no need for charging equipment to enable ‘wait until empty, then fill up. The future is EVs connected to gred even when not charing, in order to provide backup oower.

Before outlaying on charge equipment, also consider that with wireless charging, and vehicle to grid charging, are both on the horizon, and will requiring a new charging equipment. It may make little sense to spend a lot of money on charging equipment, when that equipment may only be an interim solution.

Rather than overkill, it can make sense to know what you need.

For most people, being at home means mostly urban driving, and while EVs often fail to match their official range on the highway, EVs usually exceed stated official range in urban driving. The charge needed for urban driving may be less than expected.

Almost all 2021 model EVs have a range of at least 350km of urban range, which means only needing a full charge overnight at home, only on occasions you need to drive around 300km on each of two consecutive days. That is, arrive home having used the full range one day, and need a full recharge to again be able to have full range the next day. Given that average of 60km per day most of us drive, two consecutive days of driving 300km and being home each night are very rare. Two consecutive days with that number hours driving each day, almost always involves staying somewhere other than home at least one night, and therefore needing to charge other than at home anyway. It is when on a road trip you typically do need fast charging, and a faster charger back at home will not help when on a road trip.

Step 1: Calculating what is a typical driving day when based at home.

But what recharging do you need? Enough recharge after a typical “driving day” when based at home.

On formulae is to divide annual distance travelled by 52 to get weekly distance travelled. While there will be exceptional weeks, mostly likely such weeks include road trips, when some charging away from home will be needed anyway, so this will usually give a good picture of the requirement to charge at home per week.

Some days of the week may lower the weekly total as they are not “driving days”. The goal is to look at the typical for “driving days”, when still based at home which days are the main driving days? Are the main driving days week days, so divide by 5 for distance per day, or driving days mostly only on weekends, so many divide by 3 on the basis all the weekdays in total are just like one extra weekend driving day? Just dividing by 7 is normally going to make the distance per driving day to low, so divide by 6 or less depending on how uneven your days are. Again, it is only home based driving days, not days spend all day driving, when road trip charging will be required anyway.

Step 2: Calculating Charging rate required from typical home based “driving day”.

Having calculated what distance is travelled on a typical driving day, the next step is to consider what charge, or “energy” is required.

From ev-database.org, a Tesla model 3 has a real-world consumption of 151 Wh/km, while the Jaguar iPace, has a real-world consumption of 223 Wh/km. This means to recharge after travelling 60km (37 miles, the Tesla requires 9kWh, and the Jaguar 13.5 kWh. At US home power levels of 1.8kW, the Tesla would recharge in 5 hours, and the Jaguar in 7.5 hours.

Having the charge required for the typical driving day allows calculating how many hours will be required with the different charging rate solutions available in your area, and, ideally, checking that solutions available have not only enough time to provide the required charge, but more than enough time.

Consecutive “Driving days” vs “average days”.

That 60km (37 miles) is average distance driven by US drivers per day but need to be the typical “driving day” for any driver. What is really needed is the longest driving day that would be repeated on consecutive days while still based at home.

As an example, imagine a person who is set up for 60km per day, but for some reason has period of longer commutes of 60km each way to work at a remote site.

This means that, for example, the Jaguar which needed 7.5 hours to recharge after a 60km day, even if plugged in overnight for a more realistic 10 hours each night, would begin each consecutive day with less charge than the previous day. Each day would consume 27kWh and charging each night for 10 hours adds 18 kWh, so 9 kWh is lost per cycle. So, on Friday, after 4 previous days of 120km (74 miles) per day, and only charged at 1.8kW for 10 hours, the Jaguar would have 36kWh less than on the first day.

If the next two days were at home, it would return to full change just by staying home. It takes several days of exceeding the typical before an extra charge is needed, and even if a fast charge is needed on rare occasions, it need not be a big problem.

From the calculations above, it becomes clear that most people do not need a wall box that can charge beyond 1.8 kW, if they can plug in each night, but that does not mean it is wrong to buy a wall box.

Cable or wall-box: Level 1/Mode 2 Cable vs Level 2/Mode 3 wall-box.

Most people looking to charge just one EV, will find that even a ‘level 1’ cable with the control box inline will provide all the charging they need. If mounting a control box on the wall is problematic, then no need to think further. Note, that the control box will/should be close to the power socket, which keeps the unprotected section of cable to a minimum.

A small percentage of people need more than just a charging cable, particularly in the USA where home voltage is lower and driving distances longer, but despite high-speed chargers being heavily marketed and sponsoring influencers, there is less need than the hype suggests.

Still, anyone who would often exceeds around 600 km per week when at home, should consider at least a 15 amp, ‘granny cable‘, and for over those who travel over 1,200 km per week when based at home, a wall box may be needed. Most people only drive such distances when spending nights away from home, when the charger at home does not help.

One function of the control box is act as an even safer circuit breaker, making power, making as much of the cable as secure as possible.

With a wall mounted control box, a benefit is that the unprotected section can be kept off the ground, and ideally even within the wall.

Also, most wall mounted units can be set a slow charge if desired, which means they can be used even when the available supply current is only that of a normal mains socket. A wall box can also be shared by two EVs, but unless a household is buying two EVs almost at once, that household will have learnt enough from driving the first EV, to understand what they will need when adding the second EV.

If mounting a control box on the wall is no problem, then check pricing. Sometimes lower rated wall boxes cost very little above cables with inline boxes and may be a more aesthetic solution.

Using Extension Cables with Level 1/Mode 2 charging cables.

While use of an extension cable will increase the power lost as heat as the cable will get warm, provided the extension cable is rated for the maximum current of the charging cable, the loss will not be significant. Technically, the biggest problem is that the control box will be after the extension cable, making the extension cableability in the “red zone” of the diagram above, and thus unprotected and effectively an unsafe charging cable.

As such, use of an extension cable should be considered an emergency solution. Ideally the cable should be observed, others kept away while it is in use, and put away when charging complete. There are two preferred solutions, but they are more expensive:

  1. A longer level 1 charging cable, and 10 metre lengths are available.
  2. An EV AC charging cable, to be used between level 1 charging cable and vehicle.

While both of these solutions are safer,

The actual risk from using an extension cord is this way, should be no higher than any other outdoor use of extension lead, and any increased safety from doing it by either of the preferred methods, is going to be very marginal.

But what if a dog did bite the extension cord, or some other accident happens?

In the very unlikely event that something did go wrong while using an extension cable, not only would the question of ‘would it have made a difference’ be one of conscience, but also potentially one of negligence. Negligence is often determined by not by ‘was this safe?’ but more by ‘were all steps possible steps followed to make this as safe as possible?’.

Why use higher charging speeds?

You can buy home charging stations for most electric vehicles, even though in practice, for most situations, charging from a regular electric socket should be all you would even need at home, particularly outside of Japan or North America as in most countries the regular voltage is 240v.

The main benefit from a fast home charger that is allows only every bothering to plug in every 3rd or 4th day, or in many cases, perhaps once per week, instead of every night. Why not charge a little every night? Perhaps the ‘home’ in question a second home, or there is one place for charging shared between several cars?

It could be that for some people, it is too hard to change a mindset that ‘refuelling’ is best left until ‘the tank is getting empty’, so to plugin in every time they are home, even if the battery is quite full, means breaking a pattern established over years and years.

While the provision for fast charging is essential to electric vehicles on road trips, it is not critical for charging at home. What could become more essential in the future, is having the car battery connect to the home whenever possible, as the car battery may become part of the home power system.

Home Charing Times From “granny cable” Level 1 / Type 2 cables or equivalent.

The cables with an inline control box, as used with Level 1 / type 2 charging, are also known as “granny cables”.

Despite the negative name, these cables, or wall boxes set to the same current limit, can provide all the charging most people need.

Note that US, Canada/Mexico and Japan and have 120v power at home, while almost all other countries have 220-240v. Confusingly, US/Canada/Japan can also have high current 240v sockets in laundries or other locations, but this North America style 240v is from ‘spit-phase’ high current sockets, and very different from single phase 240v in other countries. USA split phase 240v typically provides more current than the single phase 20-240v of Europe, China, Australia, Africa, etc.

240v data here is not North American style split phase 240v.

Charging at home data (12 hours ‘overnight’ figures where possible). Note actual owner experiences tend to give high range overnight than web sites of wall box resellers, or web sites using data from wall box resellers.

I may add more examples to this table over time.

Recharging Routine: Every day? Full or 80% Charge?

Battery lifetimes are often expressed as a number of charge cycles. This raises the question:

  • Question:
    • If I do lots of small partial re-charges, will this use up my batteries charge cycles?
  • Answer:
    • NO! Two 50% recharges is one charge cycle, not two. Splitting recharges into parts can lengthen battery life, and does not count as more charge cycles.

The only reason for delaying recharging until more charge is needed, is that plugging in takes takes some time. For most people at home it may take very little time, but it may take enough time to give reason to save plugging in, if there has been only a very short trip since the last recharge.

This leads to the next question:

  • Question:
    • Should charging be left at a partial charge in order to extend battery life?
  • Answer:
    • YES: All EV batteries so far will have a longer life if charging is limited to 80%, 90% or 95% depending on the battery. Choose 80% unless finding a higher limit is equally recommended with your car and battery type, but never 100% for battery life.

So why ever charge to 100%?

There are two main reasons to charge to 100%.

Some people charge LFP batteries to 100% all the time. This will reduce their life, but they do have a longer life anyway, and it is simpler than a routine of periodic 100% charging, if car software does not make that automatic. Charging to 100% saves car makers having ever deal with complaints of inaccurate rage indications due to state of charge problems, and the battery will outlast the warranty anyway.

The importance of access to home charging.

For the many who people can’t access even a power socket for ‘Home’ Charging: beware.

Statistics on what percentage of people have parking with access to a mains socket, will vary not just from country to country, but from locality to locality, and even within a town or city, or area within that town or city. I found specifications for the UK that state that 25% of all vehicles in Britain are parked on the street when at home.

However, even some vehicles with off-street parking, do not have access to electricity in their allocated space.

For apartment complexes, providing mains electric car power in each allocated space or garage, can require the addiction of significant extra infrastructure to facilitate measuring the power usage at each allocated space, which is most often not currently in place.

Some homes have few or zero off-street spaces, and some families have more cars than spaces.

This division between those with access to a power socket for home charging, and those without, could be the great divide of the electric vehicle experience. This is not a question of access to rapid charging at home, as most people, particularly in built up areas, can achieve most of the charging they need from a regular mains socket. Even for those this is not a perfect solution, a combination of mains socket charging with occasional use of rapid charging is far, far, better than no home charging at all.

Is charging an EV more like charging a mobile phone, or more like filling up with petrol or gasoline?

Just as there are public EV chargers, there are public mobile phone chargers, but few of us ever use them.

The truth is charging an EV is somewhere in between. More people who own EVs make use of public EV chargers than make use of public phone chargers, but 95% of EV charging is done at home for several very good reasons.

To understand the problem, try a period living with a mobile phone without charging at home or at work.

Why Charge at home when there are public chargers, and some are even free?

There are two categories of public chargers, and a very wide range of charging speeds.

  • Destination chargers‘, which can be low cost or even free, but typically require 3 to 8 hours for a full charge.
  • High speed DC chargers which can charge in 20 minutes to an hour, but cost 2x to 3x more than charging home.

Both these ways of charging have limitations.

Destination charging is usually inexpensive as it mostly relies on inexpensive AC charging equipment, can operate on standard electrical power, and has access to the vehicle space used for charging ‘rent free’. However, a long visit to the associated destination is required, and that visit often comes at its own cost.

Use of high-speed DC chargers, other than for those on plans that provide free use of DC chargers, also has significant disadvantages.

  • Electricity costs more as recharging stations are resellers of electricity, increasing car running costs.
  • There is the added inconvenience of needing to find time to go to recharging stations.
  • Battery life with most batteries is reduced by rapid charges and the deeper cycles that go with rapid charging.

The free fast charging trap.

Some EVs offer a free subscription to a network of fast chargers. For the initial Tesla Model S owners, free charging was even offered for the life of the vehicle. Now Tesla free charging offers are normally for 1 year only.

Companies rarely offer free charging once profitable. Like Facebook, Uber, Google, and other tech companies, most EV charging network initially adopt a “growth before profits” strategy. Even Tesla only had its first full year of profits in 2021. Company valuations can grow for a number of years more on “how many customers”, rather than “how much profit” from customers. But eventually, there must be way to make a profit.

Moving to profits does not exclude deals for a limited number of years of free charging, as the car makers can subsidise these deals, and charging networks know that every customer of free charging, will need to pay one day.

Even if an EV comes with a package of s number of years of “free” or more accurately “pre-paid” charging on a charging network, it is very advisable to do the calculation on how much extra it would cost realtive to home cahrging to remain dependant on that network once

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Dedicated EV Owners do survive, but it is not easy, nor for everyone.

The stories listed below of people who do manage to survive when owning an EV with no access to charging at home.

Almost every article is by an EV evangelist who loves owning an EV, typically provide solutions that will be most relevant to other people highly motivated to own an EV.

If living in an apartment or rely on use of on-street think Twice Before Buying an EV.

Mostly because of the billing problem as described below, most apartment complex car spaces have no access to power suitable to enable EV charging. An upgrade to apartment complex infrastructure is required before residents can charge EVs.

I have a separate paper on charging for apartment complexes, and there is a section on street parking charging solutions on the main ‘EV charging reference’ page.

There is also a separate paper disusing the problem and possible solutions for those who only have on-street parking.

These are the main reason for not being able to charge at home,

Some will have suitable charging at work, but otherwise, at this time, for these people owning an EV is going to be far from the experience it should be. The best experience requires charging from home.

Lack of home charging creates an Economic Disadvantage.

For a move to electric cars across society, this home charging problem requires serious attention. Society has had 100 years to adopt and evolve around fossil fuel cars, some evolution is now required around electric vehicles. This is the key evolution required.

Lack of home charging results in a loss of time and/or money. Some people are able to locate destination chargers which provide charging at a cost not significantly higher than available to those who can charge at home, as demonstrated in the examples above, but this takes as time, is not dependable, and does not work at all for some people or location.

The bootom line is, people without access to home charing need to be prepared to pay 2x to 3x more for the electicity to power an EV.

There is also a second factor, and that arises from the transition of the electrical grid to renewable energy. Renewable energy such as solar and wind can only replace fossil fuels if supported by energy storage, and the most cost effective and lowest environmental impact solution is to harness the storage of the batteries of electrical vehicles.

At some point, not only is it likely that people without access to home charging will pay more for the energy to power their cars, but their lack of access to energy storage of their car battery would result in them needing to buy an extra battery or pay more for their home power.

There is a social question to be answered.

Destination Charging: Less Rushed Recharging Away From Home.

Introduction.

Destination charging is “charging while your are there” at a ‘destination’ or location you that were going to visit anyway, even if you were not charging. Some ‘destinations’ provide chargers to allow patrons to “charge while visiting”, either at commercial rates, or even for free, as a way to help attract more patrons.

These chargers are not the rapid, charge in the minimum possible time road trip rapid DC chargers, but chargers designed to give a useful amount of charge during the duration of a visit to a destination.

Tesla provides a specific list of “destination chargers” around the globe, but plugshare.com also enables finding each category of identifying destination chargers.

The technology is either ‘level 2/type 3‘ AC charging or lower speed DC charging. Some ‘destinations’ require patrons to bring their own AC charging cable. While the technology is not very varied, the reasons why someone would use destination charging are varied, and I cover some here.

Accommodation Based Charging for when not staying at home.

Charging while sleeping normally means replacing the range used in the days driving. When at home, this would normally be less than 60 miles or 100km, but during a trip away form home, a full charge overnight is often required. Even if a full charge takes 8 hours while sleeping, that is still less of the drivers time than waiting 15 minutes at a rapid DC charger, as all the driver has to do is plugin at night and then unplug in the morning. As long a the price is competitive with rapid DC charging, the availability of of an overnight charge can be a compelling when choosing accommodation.

Carparks and public chargers: A lower cost, or free, alternative to home charging.

Destinations such as shopping or entertainment precinct car carparks, can offer several spaces with EV charging facilities, typically as ‘level 2/type 3‘ AC charging points. Generally, in the time available, most vehicles will only obtain only 10 to 25 kWh of charge in the time available, although vehicles with high speed AC charging in countries with 3 phase AC power could obtain as much as 45 kWh.

But why, if not on a road trip, bother to charge other than at home?

  • Usually, because these charge points offer lower cost power even than that at home.
  • In some cases where a drivers’ weekly “city usage” pattern involves very low mileage, drivers can even use these “public chargers in place of home charging.

Some examples of free chargers:

Alternatively, plug share offers a list of free charging stations worldwide, simply pan the map to the desired location.

Restaurants and Attractions.

Anyone operating a business where customers are likely to spend an hour or more, can add EV chargers as an extra incentive to bring in customers, particularly if they have room for sufficient solar cells to charge up batteries that power the charging equipment.

This can be particularly appealing to businesses who at least partially rely on customers who would be ‘passing through’.

Road Trip Rapid DC Recharging: Emulating a ‘gas station’ refuel.

Why can’t road trip charging match the fuel pump experience?

The reality is it can be similar to a gas station visit, and perhaps surprisingly, rapid DC charging can even waste less time a visit to a gas station. But it can also be problematic.

People could have an experience just like the gas pump when they want, by battery swapping, but in the US Tesla stopped offering it because it was not popular. Battery swapping could become popular, but universal battery swapping would be is complex, and unlikely until/unless batteries become modules. In the meantime, battery swapping will be a limited and premium offering.

There are people who suggest hydrogen cars refuel faster, but not only are hydrogen refueling stations far rarer than battery swap stations, but hydrogen refuelling is also slower than battery recharging with up-to-date technology.

The delay in having super-fast charging, is that it takes time to roll out infrastructure. The problem does not need an entirely new technology, it just needs time to roll out technology already developed.

There are three barriers to super-fast charging:

  • It will take 1 or 2 years before there are many cars that can recharge in 5 minutes.
  • It will take several more years before the chargers capable of these speeds are common.
  • Super-fast charging may be more expensive than other charging and there are times it may be less convenient than slower charging.

It may seem to make no sense how faster charging can be less convenient. But consider the comparison for stopping during a road trip:

  1. Stop at the super-fast charger, plugging in if the charger is not wireless. Wait while the vehicle recharges, then move the vehicle to regular parking space while you visit the bathroom and grab a bit to eat.
  2. Park at a slightly slower regular fast charger, plugging in if the charger is not wireless, visit the bathroom and grab a bite to eat while the vehicle charges, with no need to move the vehicle during the stop.

Surprisingly, the stop using the slower charger may result in a faster overall stop on times when people want to eat or visit bathrooms but will be slower when the stop is purely to get charge. When the choice between these options is available, then EV charging will have fully bettered the gas station experience.

Of course, there are times the super-faster charger would be worth even a price premium for the more expensive equipment:

  • For some reason, you could not charge at home, and as it is not a road trip stop, you do not need to ‘recharge the humans’.
  • No rest break is needed as there will be a driver swap, and the one person can grab food etc while the other waits for the fast charge.
  • It is in the future where the driver can sleep the whole time, and the car can just do everything.

Most of the population will not own an EV within the next few years, but almost all those that do, will not have access to super-charging, that is as fast as refuelling with gasoline/petrol, but in practice, this will only ever be a problem when on a ‘road tripand in a hurry.

This is not the end of the problems with the current charging infrastructure, as discussed here.

Making Sense of DC (road trip) Charging Specifications.

What really matters, but specifications don’t reveal: time to add range to reach the next stop.

While ‘home’ and destination charging are about ‘charge per hour’, rapid DC charging during a road trip is more adding range to reach the next refreshment stop, journey way point, or EV recharging stop.

As explained below, the long an EV is ‘on charge’ the slower it will be charging. This means efficient trip planning is all about more, short charging stops.

In the ideal situation, every approximately two hours, the driver takes a break, and the EV can charge during that break. In fact, if you can get enough charge during the people’s break, then a stop can take less time with an EV, because unlike with refuelling, charging doesn’t need supervision and can happen at the same time as people eat or rest. Unfortunately, while charging keeps getting faster, as of writing in 2021, most EVs still often need longer to charge than drivers need for their own break.

When charging takes longer than the desired stop, every extra minute spent DC rapid charging adds to the time it takes to reach the destination, so the goal is to stop crging as soon as their is confortably enough range to reach the next stop.

Typically, with EVs, charging gets slower as charge increases, so for most stops, what matters is how long until the car will have enough charge to comfortably reach the next logical stop on your road trip. This is not determined by specification of ‘maximum kW charge rate‘ alone because:

  • The more efficient the car, the further it will be able to travel for any given amount of charge.
  • The actual rate of charge is determined by a ‘charge curve’ not ‘peak charge rate’
  • Not all chargers will provide the same charging speed.

There is a logical time and distance until the next logical stop if at all following recommendations on taking breaks. The information you really need is how many minutes of charging to gain the required range to reach that logical next stop, as outlined below.

Peak charge rate means little, it is charge curve that matters.

Car specifications often have a maximum rapid charge rate, expressed in kW, as this is a way to reduce charging speed to a single number. For example, the Mercedes EQA has a maximum charging rate of 112kW. Unfortunately, the number alone can mean very little.

EQA Charging curve.

This ‘peak charge’ number is not very useful for calculating charging speeds or times, as in practice, it can be more like a guarantee the car will never charge faster than that number. When charging, that maximum charge rate may never even be seen, or seen only for a very short time. Plus, when comparing two cars, the car with the lower number may actually charge faster. What the maximum charge rate does reveal, is what speed charger is required for optimum charging speed.

The charging curve is a graph of charging speed at every point of a full recharge cycle, which gives the real information needed to calculate charging time. Normally, that peak charge speed only applies when the battery is at a low state of charge, and the more charged the battery, the slower the charging becomes.

As an alternative to maximum charging rate, manufacturers usually give a more helpful number like:

  • 10% to 80% charge in 20 minutes.
Specifications don’t reveal real charging times.

This type of information is more useful, in that it reveals the speed of charging in a very specific, although somewhat optimum, set of circumstances. Of course, you are unlikely to arrive to charge with exactly 10% of charge, nor finish charging at exactly 80%. The ‘fine print’ is that to achieve the rated charging time, the battery must be at ideal temperature, and the charger must meet required charging speed.

When comparing EVs, even this 10% to 80% measurement needs interpretation, as the smaller the battery, the less impressive it is to charge 70% of that battery in a given time. Further, the less efficient the EV, the less distance can be travelled on a given number of kW hours.

Calculating charge times: Use real world data or a charge calculator, and experience.

It is not easy to calculate charge times, because EVs do not charge at a constant rate, and many factors affect charging times. There are some charging time calculators online like this one, and Bjørn Nyland has YouTube videos that provide real world data on charge times during 1,000 km trips.

What is not always clear from Bjørn’s videos is how to optimise charging times over a trip, and in practice nothing beats experience. Unlike Bjørn, most drivers also get a lot of experience in their own vehicle.

Although often data is on 10% to 80% charge times, this is just a start on the best way to charge. While 10% as a lower level, and 80% as an upper level are fairly typical for specifications, different cars will have different ideal lower and upper percentage levels, and even with those that quote an upper level of 80%, typically are already well below their fastest charging speed when at 80%.

Specifying charging between a range is providing some very useful guidance. Waiting until below 10% to charge or continuing above 80% will likely be poor time management.

Ioniq 5 charging cure.

But consider this graph for charging an Ioniq 5. The first 5 minutes of charging are adding the greatest distance per minute, and almost twice the range per minute being added at 20 minutes.

Other graphs for the Ioniq 5 show that peak time occurring slightly later, most likely as the car started charging with a colder battery, but all have the peak charge occurring in the first 10 minutes, then the charging rate falling to half by 80%, and falling back significantly after 80%.

Earlier on this page there was charging curve for a Mercedes EQA, and here is a curve for a Tesla Model 3 Long Range.

With any EV, even though both would be adding the same range, charging from 50% to 100% would take longer than charging from 10% to 60%.

With that Telsa curve, it would take more than twice as long. An experienced driver would know that holding off charging until close to 10% charge, and then only staying on charge until around 60% will result in less time stopped overall.

Don’t fast charge to 100% unless otherwise busy, learn the move on the next point.

As all the charge curves shown here indicate, the fastest charging is normally only possible when state of charge (SoC) is quite low. Charing a battery from empty to half, will be faster than from half to full, and in some cases, a lot faster.

Some stops during are longer by nature, and often an EV can be on charge while enjoying lunch, visiting an attraction or exploring a town. During such stops an EV may reach more charge than was needed.

But for other stops, it should be all about get as much charge as needed, and then more on. The ‘gas pump thinking’ of ‘normally fill up’ does not make any sense with an EV.

The charge percentage at which it becomes best to move one varies from EV to EV but no EV so far as of 2021 does not slow at all when approaching 100% and fast charging. Charging to 100% great for overnight charging before a days’ driving, but charging to 100% should be the exception, no normal practice.

Every EV has a point at which charging slows, and this should be balanced against when it makes sense for the driver to stop, and what range is needed to reach the next desired charging point, or the destination for the day.

EV chargers, and usually also the vehicle display, will show the current charge rate, and owners can quickly learn from experience on road trips when it is time to move on. The problem with learning from experience, is it could require a few inefficient road trips, and as most people rarely do road trips, being too inefficient on any road trip just to learn how to best charge is not ideal. The alternative can be EV route planning software like A Better Route planner, or the planning option in plugshare, although caution is needed as software often does not have the charging curve for newer vehicles, or those less popular in the location the software developers live. Best to check other information agrees with suggested charge points.

At different points of the charge curve, a different number of kilometers is added per minute of charging, but it is possible to calculate range per minute added over the main target part of the charge curve.

The target part of the charge curve will require a specific number of minutes, for example with the Ioniq 5:

With a 350 kW DC charger, IONIQ 5 can charge from 10 percent to 80 percent in just 18 minutes. According to WLTP cycle, IONIQ 5 users only need to charge the vehicle for five minutes to get 100 km of range.

Hyundai: Ultra-fast battery charging (Web site in 2021)

The Ioniq 5 comes at this time with two battery sizes, 58kWh and 72.6kWh, and both charge from 10 to 80% in the same 18 minutes. Although this specification is the same number for both versions, it means adding 70% of a full charge 50.82kWh in the long-range version and 40.6 kWh in the standard range in 18 minutes, or 2.823 kWh (2,823 Wh) added per minute in the long range, and 2.256 Watt-hours added per minute in the standard range.

To convert energy added as Watts into range, requires dividing the Watts by the consumption, which is ideally Wh/km (or kWh/Mile), or multiplying by the efficiency, which is the inverse and is Miles per Watt.

Often consumption is kWh/100km, which when multiplied by 10 gives Wh/km.

While there is an EPA, or WLTP official consumption or efficiency number which is for typical conditions, what is needed is real world consumption at the speed being driven. This test shows the Ioniq 5 at 70 mph achieving 2.7 miles / kWh, which would be 230 Wh/km, and despite having a test at 130 km/h and another with speed less clear, that is the best I have found overall, although it was in cold weather with the AWD version, so with either the 2WD model or in better weather better results would be expected.

So, using the data from the AWD long-range Ioniq 5 as an example, to convert to range added every minute on a charger:

  • From consumption:
    • 2,823 Wh ÷ 230 Wh/km = 12.275 km of range added every minute.
  • From efficiency:
    • 2.823 kWh x 2.7 miles / kWh = 7.6 miles of range added every minute.

Refueling on a trip at 110 km/h or 70 mph, to travel for 2 hours will require that full 18 minutes. This means the standard range mode with the smaller battery, will need charging beyond 18 minutes, and therefore, being driven at 70 mph in cold weather, the standard range AWD model is going to require being recharged in the ‘slow zone’ to be able to add enough range for two hours driving. A trip will be faster in this case if stopping just a little more often, but with shorter stops.

People Need Recharging Too: Human Recharge Ratios.

When on a road trip, it is recommended, that the driver rests every 2 hours for around 15 minutes. Some people ignore these recommendations, and other instead use multiple drivers, but until there is genuine level 4 or level 5 self driving cars, it is recommended to take the breaks even if swapping drivers.

In a perfect world, 15 minutes of recharge would add enough range for two hours of driving, which would mean the EV is ready within the recommended rest time for humans. Since plugging in an EV is fast than the refuel time for an ICEV, perhaps an extra 5 minutes every second stop to allow for refuelling an ICEV every second stop before an extra time the EV takes to recharge sufficiently can be considered lost time.

In practice, not every ideal stop for humans would have the ideal car charging equipment. There are road trips where the it is the journey and not the destination, and these trips normally have more generous windows for charging. When it is all about getting to the destination, the ideal EV would have a range per minute of 16km or better, and currently there are only two entries on the above list that meet this. Fortunately, around half of the mainstream EVs being released in the next year would be capable of 16, and things will only get better after that.

Meantime, look carefully at the recharge range per minute when considering an EV that will do lots of road trips.

CCS Charging: What charging speed can I really get from a DC charger?

There are Tesla superchargers which follow their own standard, although outside North America and China Tesla EVs also use the CCS system, and for most of the world, charging is all about CCS.

Both peak charge rates and charging stations have power expressed in kW (kilowatts). For an example, a 50kW charge station can provide up to 500 volts at 100 amps. Obviously, the peak charge rate can only be achieved at a charger that can exceed that rate, so a car with a peak charge rate of 120kW should achieve that rate at 150kW charger but will never exceed 100kW at a 100kW charger.

The original 50kW CCS standard provided for 500 volts and 100 amps. Both are maximums. Power = volts x amps, so this provided for a maximum of 50,000 Watts, or 50kW. However, if your car runs on a lower voltage, and most EVs as of 2021 are around 400 volts, there may still be only 100 amps available. On a 400v car, this would mean 40kW maximum. So do not assume the rating of the charge station is what you will get. There are many 50 kW charge stations in the field, and even with a car that can charge faster than 50kW, the charge rate may never reach 50kW, because the real limiting factor may be current or Amps.

The next standard, CCS 2.0, not to be confused with CCS type 2 plugs, increased the maximum charge to 150 kW. I had thought this was 500v 300a, but actual chargers seem to be 750v 200a. I am still searching for a copy of that standard, but clearly, some real world 150kW chargers are limited to 200 amps.

The latest to 350 kW standard provides for 350 amps at up to 1,000 volts. So, on an 350kW charge station, an 800v vehicle could charge at 280 kW and a 400v vehicles at a little over 140 kW.

Currently as of 2022, most cars are 400v or less, and most chargers are 500v or 750v, but some newer cars are 800v or more. Mostly cars with high voltage charging, have circuitry to allow charging from a lower voltage charger at almost full speed, but not all, which can make for very slow charging.

The first series-produced car that has an 800 V battery system is, of course, the Porsche Taycan, and it’s also a versatile one, because it can operate on 400 V. However, if you use 400 V charger, the output is limited to around 50 kW (instead of up to 270 kW at 800 V charger). The higher levels, like 100-150 kW at 400 V can be unlocked by buying an additional package (DC to DC voltage boost converter).

See “Porsche Taycan” in the article: The multi-charging (800V/400 V) system is versatile…

More recent 800v or 900v cars, such as the Hyundai/Kie e-GMP cars, boost 500v supply to 800v, or like the Lucid Air, can charge the battery as two half voltage batteries when on lower voltage chargers, and this will not likely be a common issue going forward.

When to rapid charge: Only when absolutely necessary.

Rapid Charging Is Not Normal Charging and is expensive: Avoid it when possible.

Don’t rapid charge often! There is a reason I moved this section below home charging.

Limit the use of rapid chargers to when necessary. There are 3 limitations to rapid charging:

  • The cost per kW will typically be 3x to 4x the cost of home charging.
  • You normally need to ‘hang around’ or to be available to move the vehicle when charged, as rapid chargers are usually in demand shared resources.
  • There is a risk that too much rapid charging can limit battery life.

If you are using rapid charging on days when you will sleep at home that night, you are probably doing something wrong. For most people, over 95% of EV charging is home charging, and rapid charging is for road trips. Plus, special temporary, deals aside, it is around 4x more expensive.

How often do you go on a ‘road trip’? A ‘road trip’ means either, at least one entire day mostly spent driving, or one or more nights away from home. For most of us, these do not happen that often, but the capacity of a car to do a road trip is very important to us. Like the top speed specification of a Ferrari that doesn’t actually get driven fast often, knowing you can do it if you want is important.

For most people, fast charging is only every used on road trips, but it does matter, and it can be a sensitive issue, as historically EV recharging has been really slow, and it is still not perfect.

So how fast an EV can be charged from almost empty is a specification that gets a lot of attention, but if you end up doing it often, something is wrong.

Generally, for most batteries, rapid charging shortens battery life. While you may rapid charging your phone, the battery is less valuable and cars typically remain in use longer than phones.

Road Trip Rapid Recharging EV or Refuelling ICEV: It is naturally different.

We may not give it much thought, but even with an ICE vehicle, road trip refuelling is usually different than filling up when not on a trip. Travel is most often with a group or the family, and the stop may also be a bathroom stop, and a meal break. There is usually a different feel then fitting in the periodic refill into local trips. With an EV, that difference increases, because this is normally the only time you use a fast charger.

When refuelling an ICE (internal combustion engine) vehicle on a road trip, it is normal to fully fill the tank. Why not fill the tank? It has little impact on the time taken, and it gives more range before the next refuel is needed. We don’t think much about how long it takes to fill the tank with fuel, because unless we drive a huge truck, time difference between fill and partial fill makes little difference. The visit requires turning off the highway, getting to the pump if there is a queue, and the paying can step can take as long or even longer than the filling time. The filling time is just part of the overall stop, and how long the filling takes is not normally that significant. takes to fill the tank.

When recharging an EV (electric vehicle) on a road trip, there are reasons why it is not always best to ‘fill the tank’:

  • For some EVs, charging that last few percent is slower, and not worth the extra wait, so it can be best and most time efficient to recharge only to 80 or 90%, depending on the vehicle.
  • Recharging can generate heat in the battery, and the longer the recharge, the more heat, so more frequent partial recharges can a avoid a car reducing recharging speed to avoid excess heat.
  • Available rechargers may be slow, making a ‘top up’ and then travelling to a faster charger the best solution.
EV charging station within outdoor parking area.

Paying for recharging differs from traditional payment for refuelling. Chargers are all pay at the pump and there is normally no associated cashier. While with traditional refuelling there is normally a staff member somewhere, most often there is no human involved at all with recharging. Modern chargers can communicate with the car, so connecting the charger connects communication with the charging network operator. If there is already an account with the correct options selected, the cost of charging cam be charged to the account of the car owner automatically. Otherwise, paying is often through an ‘app’ on a mobile phone, and there can be lower prices on charging networks if the car owner is a subscriber. It can make sense to become a subscriber for the duration of a road trip. Electricity from the charging network operator can be more expensive than directly from the electricity company as may be the case at home, although charging networks can offer special deals that become bundled with a car purchase.

With an EV, in 2021, a recharge stop should require no more than 20 minutes with newer vehicles but could take 40 minutes with some models. How long should be allocated for a given recharge can also depend on what there is to do while recharging. Is it time for breakfast, lunch or dinner? If you were going to be stopped anyway, even a slower recharger can be time efficient.

If a road-trip stops will include trying to feel refreshed and perhaps involves a meal and bathroom stops, then there may be no time penalty as these things can happen during charging, unlike with an ICE refuelling. However, if in a hurry, todays EVs can extend how long your road trip stops can take.

The EV Road Trips Achilles Heel: Charging time becomes a travel overhead.

For every 100km or 100 miles travelled, there is both the time to travel the distance, and the time to recharge the battery power used in travelling that distance. On a trip within the range of the EV, the charging can wait until reaching the destination, but on a trip of, for example, 1,000 km (600 miles), almost all current EVs will require charging en route, and this will add to journey times.

Reference journeys of around, or just under, the 1,000 km or 600-mile distance include:

  • New York to Detroit: 9h 23m.
  • Paris to Nice: 9h 12m.
  • London to Inverness: 9h 35m.
  • Syndey to Brisbane: 9h 30m.

The times are driving times from google maps and will vary according to traffic and weather conditions. Driving in a fossil fueled vehicle will also require some time for fuel stops and bathroom breaks but would be faster than driving an EV and charging en route.

If the driver also took rest and meal stops, and charging occurred during those rest and meal stops if driving an EV, the time difference could even vanish, but it is still useful to know how long the time difference would be without taking refreshment and meal breask.

What would the time different be? It would differ a little from country to country, but as the average speeds for these examples are similar, that variation would be minor. However, the variation from EV to EV would be significant!

It turns out, there is at least one person on the Web compiling a database of times for many vehicles, and times vary from 30 minutes to 2 hours and 30 minutes.

Real World Driving DC recharge Range per minute at 110 km/h: from Bjørn Nyland.

Bjørn Nyland 1,000 Challenge.

EV vlogger Bjørn Nyland tests car using his 1,000 challenge in Norway. His reference time for the challenge ‘using a fossil refence car‘ is 9 hours 25 minutes (9:25) at an average of 106.2 km/h. While in theory if remaining exactly at the speed limit and without stopping at all, the journey could have been 9 hours and just over 5 minutes. This is not the real world, and 20 minutes lost between one refuelling or two stops and traffic delay when driving 1,000 km is very efficient in his reference long range hybrid. Unfortunately, the stops with the ICEV were not measured, so I am going to take the theoretical 9:05 minutes time with no stops and zero slow traffic as the reference. This could make the numbers for EVs worse than reality, but this is the limit of the data.

Comparing a selection of cars from Bjørn’s data using their excess time over the reference as being recharge time to calculate range per minute from recharging at 100 km/h reveals:

  • 20.0 – 2021 Telsla Model 3
  • 18.2 – Hyundai Ioniq 5
  • 13.3 – Audi e-tron 55, Mercedes EQA, Tesla Model X
  • 12.5 – Ford Mustang Mach-E LR RWD
  • 11.8 – BMW iX3
  • 11.1 – VW ID4 82 kWh
  • 9.1 – Tesla Model S P85
  • 8.7 – Mercedes EQC 400
  • 6.8 – Ford Mustang Mach-E LR AWD
  • 6.8 – Polestar 2 performance
  • 5.8 – Audi e-tron 50

As you can see, older cars perform much worse, and newer cars such as the Lucid Air, or XPeng models using 480 kw charging, should perform even better than any on this list so far.

Data For DC recharge per minute at 90km/h and 130km/h: Battery Life.

The you tube channel ‘battery life’ does full range tests in Germany at both 90 km/h and 130 km/h. These videos are interesting and and give insights into other factors affecting range, however tests focus on driving cars from full charge until range is fully used and then charging until the battery is completely charged. This is useful data, but differs a little from what you would get in the real world, as you will charge when convenient and you want to stop, and will get best results with most cars if you don’t wait for an absolutely full charge as opposed to 80% or 90%, unless want to be stopped for long enough for a full charge for other reasons.

The Fine Print: Be Aware Factors Affecting Real World Recharge Ratios.

With range, it’s typical driving speed, Not overall Average Speed, needed for calculations.

There are many reports online of peoples real word experiences, but caution is needed when inferring what your experience will be. I have seen calculations where people make comments such as:

  • ‘The average speed was only 90 km/h, not 110 km/h, so the real consumption would be higher’.
  • or ‘we were delayed by road works, so it was necessary to drive faster to make up time’.

The logic here is a trap. Consider three trips:

  1. A person drives for 1 hour at 110 km/h.
    • Average speed 110 km/h.
  2. A person drives for 30 minutes at 110 km/h, waits 15 minutes for roadworks, then resumes 110 km/h for 30 mins.
    • Average speed 88 km/h, but average driving speed is still 110 km/h.
  3. A person drives for 45 minutes at 130 km/h, then 15 minutes at 50 km/h.
    • Average speed 110 km/h – but 97.5km of the 110 km was at 130 km/h, and will likely use more energy than driving the entire 110 km at 110 km/h

Number 1 is obviously all travelling at 110 km/h. But number 2 is also all travelling at an average 110 km/h. The 15 minutes stopped lowered the average speed for the day, but had no impact on the amount of charge required for the trip. Stopping for 15 minutes lowers average speed, but not the driving speed, which is still all at 110km/h. If the person in number 1 was asked to wait at the finish for 15 minutes before calculating the average, they would also have the same 88 km/h average.

For number 3, the car travelled 97.5 kilometres at 130 km/h, which is 90% of the distance. The 15 minutes of driving the last 12.5 km slower, will not suddenly recover the charge/fuel that was used when driving faster. The only thing that can be learned from this number 3, is the range available when travelling 75% of the time at 130km/h, in combination with 25% at 50km/h. If this is a typicl mix, then it is useful for that max.

Many Other Factors Effect EV Efficiency.

Internal combustion engines are less efficient at best, and are rarely at best, which results them being around 5x less energy efficient than electric vehicles in typical driving. This means everything else that effects efficiency becomes more noticeable in an EV. For this reason electric vehicles use the more efficient heat pumps in place of traditional air conditioners, as every thing that uses energy matters more.

The result is all of the following factors impact efficiency, and thus recharge ratio:

  • Availability of Optimum Charging.
    • Vehicles such as the Ioniq 5 could perform better in Bjørn’s test once faster chargers are available.
  • Wheel size, with smaller wheels and taller tyres usually more efficient.
    • 19″ wheels usually give longer range than 20″ or 21″
  • Road conditions such are rain or snow.
    • In heavy rain, consumption will increase.
  • Temperature Extremes.
    • Batteries operate best within a temperature range, and it can take energy to keep them within this range.

The Future: Solar, Wireless and Vehicle to Grid

see Solar above

Wireless Charging: The Next Step?

Wireless Charging At Home: Still rare, but becoming available now.

Having to plug in each night when you park may not take long, and if we can remember to charge our phones, it may not seem to much of a burden, but just imagine if as you a pulling up, the car automatically guides itself to the right position to recharge. This is new, but the it is already down as an option with Hyundai Genesis EV60 and the BMW530e. As the WiTricity wireless charging follows an open standard, and is said to be as efficient as a cable, wireless charging could take over. VW aims to wirelessly charge a Porsche Taycan to 80% in 10 minutes.

Wireless Charging On The Move: In Early Trials.

Like the technology used by our smart devices, the system needs vehicle-mounted receivers to work. According to the company, this is something that has not been implemented yet as a factory feature by any renowned carmaker but can be easy and cost-effective to add on existing and future EV models.

In terms of logistics, the only inconvenience is that a portion of the asphalt needs to be removed and replaced. Other than that, the system can connect to existing power grids without the need for additional infrastructure or transformation stations. It uses management units placed on the sides of the road to communicate with the receivers on the vehicles and transfer energy.

ElectReon is involved in multiple pilot programs to test the feasibility of this technology. Recently, the company has completed the deployment of its dynamic wireless charging system on a 1.65-km (1.02-mile) public road in Gotland, Sweden.

Sweden Successfully Tests Wireless Charging Road Set to Revolutionize Mobility

Just as wireless charging is becoming the normal with mobiles, we could move to a world where ‘stopping to refuel’ just doesn’t happen. We recharge for the lowest cost at home overnight, particularly if we have solar power, and on the move on the highway on a road trip, all for lower cost than refuelling an ICE vehicle.

Updates:

Vehicle to Grid.

Already, the Ford F150 lighting supports Vehicle to grid.

“The companies will test the ability of Ford’s new F-150 Lightning electric vehicle to send power flowing back to a house and connect with the grid, Ford Chief Executive Officer Jim Farley and PG&E Chief Executive Officer Patti Poppe said during an event Thursday night at the CERAWeek by S&P Global energy conference in Houston.

Ford’s battery-powered F-150 is the first of its kind that can be used as a backup power source. PG&E will test five trucks this year, Poppe said in an interview.”

https://www.bloomberg.com/news/arti…test-electric-truck-as-power-source-for-homes

In the future, vehicle to grid could become an essential feature. In 2021, vehicle to grid is merely another future technology, that means any home charging infrastructure installed now may become obsolete.

Solar: Free Power.

Solar EVs. (see dedicated Solar page)

There are soon to be released cars:

Unlike the solar challenge races, a regular car cannot travel 1,000km (600 miles) on the solar energy collected in just one day, but adding up to 60km of range for each day is possible, and given the average distance driven per by vehicles, then that may just be enough to keep the battery sufficiently charged most of the time for most people.

More articles on solar vehicles:

Free power and even a solution For Cars Parked Outside?

Beyond vehicles with inbuilt solar, the other option is units to either cover a car, or connect to a car.

The Tesla Cybertruck will have a solar “bed” option that will add 15 miles (24 km) per day according to Elon Musk.

Tesla not only has solar charging plans for their Cybertruck, they have also shown a charging trailer, but Tesla has nothing is in mass productions at time of writing. Third parties do have working solutions for solar trailers.

Solar Car Covers & Blankets and Accessories.

EVsolarkits.com roof

Rather than having solar panel built into the car, another option is to have either a car cover with solar cells built in, or a “blanket” of solar cells which can be laid out on the ground.

The blanket of solar cells is potential solution for travel to remote locations, or those with a private place for parking that has no access to power.

The solar car cover is a potential solution for people who park on the street, with limited distances travelled during their normal week. The current 105 km week of range quoted in the article above does equate to only just over 5,000 km (3,100 miles) per year, but this is excluding road trips, when rapid chargers would be required anyway. The company hopes to triple the range per day, which would then be sufficient for the “urban” part to their life for most vehicles, but even at the current power generation level it would be a solution for many people.

Off Grid Solar Vehicles.

Another type of charging is charging when parked at a remote location. This is most relevant for vehicles that may spend long period of time at a remote location such as campers.

A proof of concept vehicle has already been able to gain 130km (80 miles) of range per day. All of this additional range is completely without cost of carbon footprint.

There are also a number of camping conversions and camping trailers that propose using solar power for not just camping, but also to charge the vehicle.

Technically.

How does recharging work?

General Principles.

All recharging requires providing a DC voltage across the terminals of the battery, with a potential difference greater than the internal voltage of the battery at that time. The greater the difference in these two voltages, the greater the current that will flow into the battery.

Note: SiC is Si (Silicon) C (Carbide).

AC Recharging: The Onboard Charger (OBC).

Battery charging requires DC, so starting from AC power, requires the OBC circuitry in the car to do all the real work.

Typically the first step will be a Power Factor Correcting (PCF) circuit which converts the incoming AC power to DC power using a direct bridge and capacitor, resulting in AC converted to raw DC, while ensuring the load on the AC appears as close as possible to a pure resistive load.

LLC Converter.

The next stage, normally an LLC converter, where L=inductor, and C= capacitor, takes the raw incoming power, and converts this to either a desired voltage, or whatever voltage will ensure the desired current. Since the battery provides the resistance, and V=IR, the same result can be obtained either by tracking voltage, or current.

Overall, the efficiency of AC charging is all determined by the car.

For AC charging a “Wall box”, sometimes misleadingly called a wall charger, and correctly called EVSE or Electric Vehicle Supply Equipment, is used. Such equipment can be directly wired for higher current and/or three phase electrical power, contained a high voltage relay to ensure the connector and cable only have power when charging, and include a socket specifically designed for the high current AC power.

AC Charging Current: 7kW, 11kW, 22kW, 43kW.

In the North America, Japan and a few other countries, there is also 120 v power, but generally, AC power can be 16 Amp, 32 Amp, and as only ever in practice implemented in the Renault Zoe, 64 Amp, and be either single phase, or 3 phase, all at a nominal 225 volts.

The yields either:

  1. 32Aamp x 225 volts = 7.2 kW (7 kW)
    • Either 1×7.2kW or 2×3.6kW
  2. 16Amp x 225 volts x 3 = 10.8 kW (11 kW)
    • 3 x 3.6 kW
  3. 32Amp x 225 volts x 3 = 21.6 kW (22 kW)
    • 3 x 7.2 kW
  4. 64Amp x 225 volts x 3 = 43.2 kW (43 kW)
    • 3 x 14.4 kW

Almost all EVs use either option 1 or 2, and those using option 2 deliver 7.32 kW from a single phase by using two of the 3 3.6kW AC-DC circuits.

Option 4, 3×64 Amps, was really one ever used by the Renault Zoe, prior to the availability of DC charging stations, and while a small number of cars support 22kW, almost all now only support 11kW, with most even including the GMC Hummer deciding 11kW is sufficient for home charging. The standards for CCS and IEC 62196 specify single phase of up to 80 kW in the US on CCS1 and up to 70 kW single phase on CCS2, which also supports 3x 63 kW for three phase AC power.

DC Recharging: The External Rapid Charger.

With DC charging, all the conversion to the DC with the desired voltage and/or current is provided by the “charging station”, leaving on the logic to continually determine either the required current, or voltage required to the car. Although all DC charging points have power specified as kW, in reality they have limits to both voltage and current, and the specified power is only delivered to a car requesting maximum voltage and current. For example a 50kW CCS charger can deliver 100Amps at 500Volts. Since cars usually want less than 500 volts, they will not get the full 50kW.

Voltage conversion: Generating Required Voltage DC Power.

Central to the on board EV charger, and external rapid chargers, is electrical circuitry that take electricity at one voltage, and covert that power to DC voltage at the right power.

This is also the same type of circuit found in plug packs and inside all manner of appliances, and is know as a switch mode power supply. These “switch mode” circuits can take a wide range of voltages and produce the required. On plug packs and appliances, they will usually accept AC voltage from 100 volts to 250 volts.

However, while all these circuits typically accept AC power, all they ever do with that AC power is directly convert the power to DC using a diode bridge, as explained well in the Wikipedia page, together with a capacitor to smooth the power.

The general principle is that the power supply provides this DC power to a high voltage transistor which acts as switch tuning the power on an off to produce a high frequency square wave of DC pulses.

The square wave can be fed to a transformer, which produces an amount of power that can be varied by varying the width of the pulses of the square wave.

The high frequency AC power from the transformer is again converted to DC using a bridge and capacitor. Simplistically, everything that requires power represents a load with a resistance. Basic electronics tells us that combining P=VI (power = voltage times current) and V= IR (voltage is current times resistance) reveals P=V2/R. This means for any resistance, voltage will be determined by the power. Increase the power and the voltage rises, decrease the power and the voltage will fall.

But don’t most electric car motors run on AC?

All efficient electric motors, as used in EVs, require the power supplied to them to be tailored to motor speed and power required at the the time. This requires supply by an efficient variable power supply, and and efficient variable power supply requires DC power, even when the output power to the motor is AC.

While traditionally, only DC motors could run at variable speeds, with a variable frequency AC power supply as used with EVs, AC motors can also run at variable speeds, and this is the arrangement normally used in EVs: DC power to a variable frequency AC power supply, which drives AC motors.

All mainstream modern EVs use either permanent magnet AC motors, or induction AC motors.

However, the AC is nothing like mains power power AC. Firstly, synchronous AC motors spin at the frequency of the AC, which means the AC supplied cannot run just on 50Hz or 60Hz AC or the car would have one fixed speed. The asynchronous motors also require variable frequency AC to run at variable speeds.

Charging Efficiency: 85% to 90%.

This report from car and driver states that 12% to 15% of energy is lost during charging. This is the total energy loss, and most (losses account of up to 10%) of the losses will normally result from the conversion of AC power to final DC stage, although there are some (losses up to 5%) additional losses due to cabling resistance and battery internal resistance.

When using an external DC charging unit, expect around 10% losses to occur internal to the charger, before the point where the energy is metered for delivery to the car. This means with DC charging, most of the losses are “someone else’s problem”, except for the reality that losses result in heat, which may under some circumstances, such as very hot weather, result in throttling of the power supplied by the charger. If charging at 100kW, 10% losses would be 10kW, which is 5x a high power electric radiator, and quite a substantial amount of heat.

With DC charging the losses withing the car would normally be 5% or less, which could still amount to 5kW and is still considerable heat. These losses will be mostly due to the internal resistance of the battery, but can also occur in the cabling, and even in the heat pump of the EV.

With AC charging, 15% of 7kW is 1kW and of 22kW becomes 3.3kW, which will normally be less than losses from charging at DC 80kW or more, and thus should not result in any limiting of charge rates.

USA Specific Data: Voltage, Plugs and Batteries.

A large percentage of information on EVs originates from the USA, which has 3 differences to the rest of the world:

  • 100v-120v electrical supply, North America, Japan and US territories.
  • Tesla vehicles use proprietary plugs, as opposed to standard plugs used in Europe, Asia, Oceania.
  • All vehicles, including Tesla, so far until recently use ternary batteries with more limited charging curves, whist outside of the USA, Teslas can already be using LFP batteries.

Batteries Charing Profiles: LFP vs Ternary.

Batteries In Use.

Currently there are three types of batteries in use in EVs, LFP and two types of “ternary” battery, NCA and NMC.

As of early 2022, all EVs by traditional car brands use ternary batteries, as do all Teslas in the USA, and longer-range Teslas elsewhere. Within China, LFP batteries are around 50% of all batteries as of early 2022, but outside China, LFP is only in some Tesla models and all exported BYD vehicles.

Characteristics: Ternary Batteries Vs LFP.

These NCA and NMC batteries have so far given a higher capacity for the same weigh and volume, but come with a number of drawbacks in comparison to LFP batteries ternary batteries:

  • Present a far greater fire risk.
  • Have a shorter lifespan, around 1/2 of LFP batteries.
  • Require more careful charging, with charge above around 80% being undertaken at much slower charging rates, and above 90% to be used only one road trips on occasions where maximum range is required.

Caring For Ternary Batteries.

Advice on battery care varies from car to car, as difference cars implement different strategies to help manage ternary batteries. Some report a battery capacity, and a separate, lower, “usable capacity” that prevents using all or some of the battery capacity that would require cautious slower charging and less frequent use.

Generally if the manufacturer provides as time for charging from, say 10% to 80%, then that is the range where the battery can if conditions are correct accept full fast charging, and outside this range, charging should be slower.

Recharging Summary and Conclusion.

There are a few key takeaways on what a person moving from an ICEV to a EV will experience at this time, in late 2021:

Access to home or office recharging is a significant improvement over refuelling an ICE vehicle, making the ownership experience a significant step forward, other than when on a road trip, as described below.

Without home or office recharging, EV recharging is problematic and a step backward from the experience refuelling ICE vehicles.

Recharging on road trips is current a step backwards from the experience with ICE Vehicles, although in in practice, the experience can depend on whether you also recharge the humans when you stop.

The biggest problems for new owner is adjusting mentally to how different charging is to refuelling an ICE car finding charging solutions for those who cannot charge at home.


Updates

Planned future updates

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