This page serves as reference on the various recharging systems and their connectors. Discussion on best practice for recharging electric vehicles, as well as which of these technologies is best used where and on what occasions, is all covered in the separate page, ‘EV recharging reference‘, and this ‘charging systems reference’ provides background to that topic.
What do we need from EV Charging? AC/DC?
EVs: A new perspective on
With internal combustion engines, there is only one refuelling system available. Most of us are so accustom to this one refuelling system that all we want is to reproduce that one system. Mostly we do not even think about how our usage of motor vehicles is mostly divided into two categories: ‘home use’ and ‘road trips’, because we have lived so long with only one way to refuel for both situations. In fact, the way we refuelling gasoline/petrol/diesel vehicle is perfect for road trips, but inconvenient for home use.
On a road trip, gasoline/diesel refuelling is just part of a welcome break. On a road trip, we need to stop and take a breaks after every so often. In theory one break at least every two hours, but aside from the need to refresh mentally, driver and passengers may need food, drink or toilet stops. During these breaks, refuelling fits well, as we need a break anyway.
In regular daily driving, gasoline/diesel refuelling is a break we don’t need. Most days we can avoid refuelling, but we do need to refuel, it often adding time to an otherwise short drive. With no convenient way to replace each days small amount of fuel used, we combine days and use the same refuelling as we use on a road trip. Several days ‘home based’ driving added together soon adds up to using as much fuel as is used between fuel stops on a road trip, and we are forced into a ‘refuel break’ that in daily driving we don’t need. In city driving, range becomes all about the number of days we can avoid needing to stop for fuel.
Electricity is more widely available than gasoline/petrol/diesel. In fact even the fuel pumps use electricity to operate, so if there is no electricity, there is no fuel anyway. Every house, office and even many camp sites have electricity ‘on tap’, while only fuel stations that exist specifically to provide gasoline or diesel have those fuels on tap. This wider availability gives more options on where and how we ‘refuel’, but different ways of refuelling requires a new perspective on what suits the different scenarios.
Charging While Parked vs Charging Stations.
With gasoline and diesel vehicles, a visit to a specialised gas station is required for refuelling. But with an electric vehicle, there is the potential to charge any time the vehicle is parked, and most cars spend most of their time parked. Turning ‘parked time’ into charging time is a new concept after owning previous vehicles, but it is that rethink that delivers the greatest convenience. Whether charging when parked at home, the office, or the shopping mall, it all requires thinking in terms of adding miles or kilometres per hour, instead of thinking in terms of refuelling only when near empty.
Home: AC Charging.
Being able to charge at home is a key part of an EV, and even you cannot charge at home, it is still essential that your EV has home charge capability, and that means charging the car has a system for charging from domestic AC. There is a complete myth that you need to be able to get a full charge at home overnight: for almost everyone, this is rubbish. People who currently buy fill up a full tank every day for their gasoline/petrol/diesel car, will need a full charge at home in one night. In fact if your pre-EV habit is to buy a full tank of fuel every second day, then perhaps you will need to get fast home charging. Statistically people who use a full tank of fuel every day or even every second day when they are at home, are very rare, as US data is on average people travel 13,500 miles or 22,000km annually, is . If it takes you several days to use a tank, it can take a few nights to fill a tank. For most people, if you can add 100km (60 miles) range overnight, you will be able to start almost every day with a full tank. 110v systems may sometime be borderline on that rage from a normal lead and early EVs with small batteries needed a full charge because they only had just over 100km range and were rather useless for a road trip anyway, but almost everyone should get 100km (60 miles range) from an overnight charge. Note EVs are most economical in town or in the city, and less economical on the highway, so 100km range will still be 100km even in traffic. But for an EV with reasonable range (at least 320km or 200 miles) it is more helpful to have a lighter cable for home charging that is less work to plug in each evening, than a heavy duty system that handles the rare situation when you used a full charge today, and need another full charge tomorrow, while at home. If the unusual does happen, you could visit a fast charger.
So, home charging only requires slow AC charging, capable of adding 100km or 60miles range overnight.
That said, using trickle charging requires a new perspective, and those who have not shifted perspective think in terms of a once every few days overnight recharge, emulating the practice before EVs. This requires extra expense and their car, on average, has less charge despite having spent more money.
If you can charge at home, over 90% of your charging will be at home.
Road Trips: Fast DC Charging.
A road trip is a car journey as opposed to a commute. A road trip could involve driving any distance between 60 to 600 miles, or 100 to 1,000 km each ‘driving day’ of the road trip. Yes, some people set even longer distance targets for some days, but most people would normal stay within these limits. Road trips will most often also involve staying one or more nights away from home.
While for the 90% of charging most people can do at home if they have home charging, EV charging is fantastic, when it comes to road trip recharging, conventional gasoline/petrol/diesel car refuelling has always worked really well.
At a fast EV DC charger, the best EVs at this time can add enough range for another 3-4 hours driving within 20 minutes, but most are far slower. Even the best EVs with their high speed DC charging are still not quite as fast as refuelling gasoline/petrol/diesel vehicles at this time, but for most people it is fast enough. Just.
Those fast best fast DC chargers can add as much as 900 miles or 1400 kilometres of range per hour (although batteries are not large enough to do this for even one entire hour), compared to 6 miles or 10 km of range added per hour that is normally more than enough for home AC charging. Even ‘fast’ home AC charging, that can fully recharge overnight, would be a disaster for road trip recharging. The bottom line is that a completely different solution is best for road trips, so EVs have two ways of adding power: a fast DC way, and a slower AC way. Each has their uses, and for many people the slower AC way is best for most recharges, but without the fast DC way being also available, road trips would be impractical.
Also note that while EV range specifications may even be conservative in towns and cities, with highway driving at over 100km/hr or 60 m/hr, EV range is worse, not better. Unlike fossil fuel cars, where efficiency is better on the highway, with EVs, efficiency s better in town.
Fast charging, at the level only provided by high voltage, high current DC chargers, becomes essential.
The Rest: Its complicated, but a mixture.
There are situations beyond charge at home and road trips. Firstly, for those who cannot charge at home. Can you charge at the office? At the mall? What about at destination restaurants? There is a separate exploration of EV range where this is covered in more detail, these other situations may need either AC or DC charging, but do not really add the wide difference between the needs of the road trip and home charging. Any EV that can handle home charging and road trips, has almost every scenario covered.
Summary: Charging Needs are poles apart.
At home, anything in excess of a charge rate that adds 100km or 60 miles range in 12 hours of charging, which is 8 km/h or 5 mph charge, will be sufficient.
On road trips, even adding adding 320 km or 200 miles in 20 minutes, which is or 960 km/h or 600mph can be marginal in some circumstances.
Road trip charging has needs around 80x faster than home charging. It is quite practical to obtain all power needed from home charging, over 90% of all needs, for free from solar power.
Electric Babel: Four home charging systems, Five Rapid DC Systems.
All The Systems.
As shown by the chart to the right, globally things are more complicated than in any one country.
While there are many systems, in any one country/continent, usually one 1 or 2 systems are common. The TLDR; is check the relevant column, and stay safe with a car where the charge area matches the image for either ‘Cars‘ or ‘Alternate Cars‘.
That practices and rules vary makes inter-continental travel require adapters, and also means reviews from other countries, not only may show charging as different, but also often mis-understand how things work elsewhere, so may provide misleading information for readers outside their country. The picture at the top of the page for Norway, is not how people in the US, China, Japan or North Korea see things, but does apply for most of the rest of the world.
AC Charge and DC charge show the different sockets used for AC charging and DC charging respectively in that region. While each charging point will be AC or DC, cars must provide both, so the plugs in cars are shown in the ‘cars’ row and ‘alt cars’ row. Because cars can have more than one socket, I have made separate rows for the most popular two combinations, but there are other less popular combinations.
What is Used Where?
CCS2 ‘World System’: EU/Australia/NZ/Africa.
Mostly one CCS2 combo socket.
This suggests a future where charging infrastructure can be universal, which would make it easy for Tesla to open their charging network.
In most countries, excluding those specifically mentioned below, almost all cars, Teslas included, the the same charging connector, the CCS2 combo socket.
The AC plug, without the lower section, is used for AC charging, and the full plug is used for rapid DC charging as on when on road trips.
Although newer Teslas have the CCS Combo2 charging system, older model S and X Teslas have the original Tesla charge plug. There is now an adapter available so that people with these cars can charge at CCS Combo2 charging points. There are also some CHAdeMO DC chargers, but this mostly now only about the Nissan Leaf and Mitsubishi plug in PHEV models. Early Leaf models had no DC charging, and only a J1772 AC socket as used in Japan, making them now require a simple adaptor in markets that standardised on CCS2.
CCS-1 USA, Canada, Mexico: North America.
Teslas in North America use the Tesla proprietary socket, almost all other cars use CC1 combo socket. This means that unlike most of the world, Tesla opening their charging network requires more than just software.
There there are some year models of Nissan Leaf and Mitsubishi Outlander that have CHAdeMO sockets, but there few charge points for these systems, which can mean owners can only AC charge.
South Korea took the decision to standardise on CCS1, despite being the only 220-240v country to use CCS-1 over CCS-2. In South Korea, there are still some cars with CHAdeMO, and some Teslas also use the proprietary Tesla charge plug, but for South Korea, Tesla has released an adaptor.
Japan uses CHAdeMO, almost exclusively, and while there is an adapter that allows Teslas to be charged from CHADdeMO, most cars need CHAdeMO for Japan, plus a CCS1 AC socket for AC charging.
China uses their own GB/T system.
Note the situation with plugs is sufficiently confusing that even normally reliabled resources such as this, tend to have errors.
EVSE: Electric Vehicle Supply Equipment.
EVSE is a standard for communication between car and charging equipment, not to be confused with the charging company evse.com. I am still collecting material for this section.
Ref material: green transport.
What are all the pins for?
Charging quickly requires high voltages and currents. Normally in homes there is either 110v to 240v AC power with wiring for sufficient current to support charging EV batteries. At home DC power is normally only used at lower power levels. This makes AC power the preferred power at home, and at any point without specialised charging infrastructure. The DC power used to charge EVs, is all about rapid charging using hundreds of volts, 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! As a general guide:
- AC: charging at home or lower speed charging, or charging small batteries such as those of PHEV.
- DC: Newer, specialist rapid charging currently capable of delivering 350 kw.
All those plugs!
Despite the desirability everyone having single charging cable that can be used worldwide, there are currently 4 different charging plugs in use worldwide for AC, and . This is almost as many as there are AC power wall socket standards, but there is hope of some rationalisation. To understand how we got so many different solutions and what all the pins do, this background section uses as an example the most widely used system, the Combined Charging System, but the same concepts apply to all systems. Combined Charging (CCS) uses two of those 5 plug types, and that system and other three systems and their plug types are each covered here.
AC power, the first 3 power pins.
The first charging was all about using standard AC power. Lots of AC power, since the goal is to get power into a very large battery as soon as possible. This makes the most basic charging cable very high current extension cord. Why not stick to the regular plugs specified in IEC pins like an extension cord? Or for something international, why not the IEC 60320 ‘kettle’ (C14) plug as to the left, or the IEC 60320 mickey mouse (C5) plug to the right?
There are three reasons plus like these were not suitable because:
- More Current is needed than either existing plug, as even C13/C14 10amp is insufficient.
- The design needed to be for daily connect/disconnect, these plugs are usually left for long periods.
- Like USB, the goal is power and data, just way more power than USB.
Original US SAE j1772: For Control Add 2 small pins.
Mains power requires 3 high voltage, high current pins, and data requires 2 low power, low current pins. While the three pins for AC power, ‘active’, ‘neutral’ and ‘earth’ are the same between all charging systems, the data sent over the data pins uses two different system. CCS uses PLC (PowerLine Communication), while CHARdeMO, Telsa and GB/T protocols all use CAN communication. Converting between the two systems is problematic.
EVs are also computers, so this is a computer connect as well as charger, in the same manner as USB cables, just with much more electrical power for the power signals.
The top two pins are ‘active’ and ‘neutral’ AC power, the smaller pins are data, and the bottom pin is earth. The socket to the left is suitable for AC charging.
Three Phase AC power, an additional 2 pins.
Three phase AC power requires 5 wires. The regular Earth, neutral and ‘active’ wires, plus 2 addition active wires. Electrical power normally is normally generated and distributed as 3 phase power. Single phase as used in normal household wiring, requires less wires but is less efficient. There will normally be 3 phases wiring in street, and to apartment buildings etc.
Where 3 phase power is available, it allows for more efficient transfer of power from the grid to the car, and in many commercial premises, 3 phase power is readily available. CCS uses standard IEC 62196, which adopted a plug originally designed by Mennekes as the 3 phase plug.
The two control signals are now at the top of the plug, with the 3 regular AC signals, active earth and neutral, across the middle row. The lower row provides the two extra pins for the two extra phases of AC power.
DC Charging, Another two pins makes 9!
The last step in the evolution of CCS power is the addition of DC charging. Over short distances, DC power can be even more efficient than even 3 phase AC power. The most powerful EV charging stations receive their power over 3 phase AC power, but in order send the most power to cars over the ideally flexible charging cable, they connect to cars by DC power.
DC charging, as the highest power method of charging uses the largest pins of all.
Some other charging systems use the same pins for both DC and AC charging, reducing the number of pins but making the system more complex to build. In all cases, the pins for DC charging will be the largest pins on both plug and socket. DC charging uses the two DC pins, plus the control pins and earth as used when AC charging.
And AC Power.
Worldwide, there are two main systems for AC power. All power is transmitted as 3 phase power, but normally while 3 phase may run down the street, it does not come to the house. The are two main systems:
- In North America & Japan and a few other countries, 120v AC is available as lines of 120v from a common central neutral. This gives 120v between neutral and either line, or 240v between both lines. 3 phase power is not normally available for residential use.
- In most other countries, three phases of 240v power are used, with at least one phase sent to each house. As these are 120 degree (2/3 ) out of phase, you can’t simple combine phases even if a house has two, however it is possible to have the third phase where required for high energy 3 phase power where required.
Since gaining over 100km (60 miles) overnight will often require 240v, to avoid excess currents, either special wiring or use of 240v ‘laundry’ socket can be required in 100v countries, making ‘plug in anywhere’ more restrictive.
Combined Charging System. (CCS, Combo1 and Combo2).
The most common CCS system in the world at this time outside of China is the Combined charging system type 2, with the pins for 3 phase in the top AC section. As per the chart, there are there two plug systems:
CCS type 1: USA, Korea, Japan
CCS type 2: The rest of the world.
CCS type1 is built on the single phase AC charging J1772 plug that was already standard in many countries, but cannot manage 3 phase AC power, and generally is less dominant in the countries where it is present.
CCS2 is the main system in countries where it is present, and in those countries begins to look like the system going forward. In CCS2 countries, most Teslas come with CCS2 sockets, not the proprietary Tesla system. There are suggestions Telsa may also move to CCS1 in via adapters in Korea, but also reports they will not change in North America.
Pluses for CCS are that sharing the control and Earth pins between AC and DC makes the plug system almost as small as the Tesla charging system, with benefits over the Tesla system of the added capability of a dedicated earth pin and support for 3 phase AC charging.
The minus is that there are the two systems (type 1 and type 2), and both AC and DC plugs change between the two systems. Also, the PLC data communication does not have the same ultimate capabilities at this time as the CAN bus system.
CCS with 350k charging is being rolled USA, Europe, Korea, Australia, and many other countries. CCS 350 kw chargers are capable of faster charging than current Tesla superchargers.
CCS Standards: CharIN?
The CharIN e.V. strives for the establishment of the Combined Charging System (CCS) as the global standard for charging battery powered electric vehicles.CharIn.
While there are CCS standards, I have not found a CCS standard body, and the closest I have found is an organisation devoting to promoting CCS standards.
CCS Volts, Amps and Versions.
There are version numbers, which can easily be confused with type numbers. Type numbers are North America vs rest of the world plug, and version numbers are the volts and amps that can be sent of those plugs. This section deals with versions.
1.0 50kW: Like most other systems CCS 1.0 began with 500 volts and 100 amps, giving a peak of 50kW.
There are also charging stations that support 500 volts at: 200 amps (100kW), 240 amps (120 kW) and 300 amps (150 kW). I have not found universal agreement on whether any of these constitute a standard from some specific date.
2.0 350 kW: It is reported that the 2018 revised standard is 2.0, and it is definite that the volts are now up to 1,000 volts (1kv) and and amps up to 350 amps, giving an 350 kW maximum on the hypothetical vehicle that uses the full 1kv. Note: this would still be only 400 x 350 = 140 kW on a 400 volt car.
AC supply equipment check safety conditions prior to connecting voltage to the car and if they detect a fault or the car signals to disconnect, will disconnect the voltage. This is done with relays. Some of the things checked include: that the cable is connected to the car; and that the cable is safe to use. (ie the electronic circuitry in the charger acts like a safety switch).
The safety checks may vary from charger to charger. Safety checks include current higher than signaled, current in active wire not same as in neutral wire (this is the safety switch operation which prevents electrocution ). Also sometimes the car may have a fault and reduce the negative signal voltage, and some chargers will then not connect the mains to the car.
AC Charging, current control.
The maximum current is signaled to the car by the duty cycle of a 1 kHz square wave on the signal pins. The minimum charge current which can be specified by any charger is 6 amps. This is signaled from the charger by the duty cycle of the square wave being 10% (ie high 10% of each cycle). The duty cycle, according to the J1772 spec, ranges from 10% for 6 amps to 96% for 80 amps. The car is allowed to draw less current than the charger signals. If the charger signals 6 amps but actually supplies less current, then the car may stop charging. This can happen with a granny lead plugged into a battery pack which cannot supply the amount of current the car needs. I know in a Tesla you can program the car to draw less than the 6 amps the lead might signal.
When the cable is plugged into the car the signal is 12 volts DC supplied by the charger. When the cable is plugged in, A resistor and diode in the car drops the voltage to +9. The charge then generates a 1 kHz square wave which will go from +9 volts to -12 volts. When the car can accept a charge it will lower the resistance between the signal pins so the pilot is now a 1 kHz square wave between +6 and -12 volts. The charger will now close its relays and provide power to the car. If the car no longer wants to charge it will reduce the resistance so the plus signal voltage is 9 volts and the charger should open the relays which disconnects the mains from the car.
Note that some chargers violate the spec J1772 and the pilot square wave just goes down to 0 rather than -12 volts. Some cars will still work with this but others will not.
China has its own standard: GB/T.
At first, the GB/T AC plug and socket look like the the type II CCS ac plug and socket, until you realise they are reversed. The plug looks like the socket and vice versa. So means, despite being similar, they are in now way compatible. The high speed DC charging plug is again unique, and even larger than the AC socket, which means the system on a car requires twice the plug space of a CCS combo-2 socket. As you can see, even Teslas in China come with GB/T, and Teslas are all built with sufficient space under the recharge flap.
Standards in China are set to change, as the new CHAdeMO 3.0 (see below) arrives.
Considering China is the largest consumer of EVs, and that many regional countries are likely to join including possibly India, the CHAdeMO 3.0 / ChaoJi initiative may well dethrone CCS over time as the dominant force in charging.ElectricCarHome
GB/T Volts, Amps and Versions.
The current (2021) version of GB/T is 500v 200 amps = 100kW. There are upcoming cars from China promoted as having over 100kW charging in China, but whether they use the same plugs, or CHAdeMO plus is not yet clear.
It is unclear whether any upgrade to GB/T will be released prior to the integration with CHAdeMO.
CHAdeMO & CHAdeMO 2.0.
The same socket continued through to CHAdeMO 2.0.
The first electric DC charging system, CHAdeMO originated in Japan in 2005. CHAdeMO plugs are big, and DC only, so another AC plug is still needed for home charging. For AC home charging, cars also still require either the J1772/CCS1 or ‘Menekes’/CCS2 style AC socket, and as CHAdeMo is large, the result is the requirement for an even bigger area under the recharge flap than with GB/T.
CHAdeMO was officially accepted as a European DC Fast Charging Standard in 2015, but in 2019 there was a proposal to transition out CHAdeMO chargers, which did not go through but instead, CHAdeMO is now only optional (as are other chargers) and the CCS Combo 2 chargers are mandatory.
No Telsas come with CHAdeMO, but Telsa owners can get an adapter (left) to charge from CHAdeMO fast DC Chargers. I have not found adapters to allow CCS vehicles to be charged from CHAdeMO rechargers, but generally there are more CCS chargers than CHAdeMO, at least outside of Japan.
A new socket. The large size and lack of international support suggests CHAdeMO may become obsolete, but there is a new proposal for CHAdeMO 3, which in theory addresses size problems, allows for adaptors for other systems, and will be supported as the official system in Japan and China and possibly also India. With and almost 1 million CHAdeMO cars out there, it is too early to write off CHAdeMO yet completely, and although the days of the current standard are numbered, the new standard if successful would also provide a future for those with the current standard.
CHAdeMO Volts, Amps and Versions.
CHAdeMO 1.0 was 50kW, 500 volts, 50 amps.
CHAdeMO 2.0 400kW, 1kv, 400 amps.
CHAdeMO 3.0 900kW, 1.5kv 600 amps, new plug integrating CHAdeMO and GB/T
Tesla: Technically clever, but Quirky.
With the Tesla charging system there is one plug and socket for both AC and DC charging. As you can see, from this pictures of the Tesla Model 3 for different markets, the Tesla US/Japan (left) connect is smallest, then the CCS-2 (far right), with the Chinese GB/T (near right) the largest, and a CHAdeMO system would be unable to fit.
The ‘US/Japan’ connector is normally supplied to North America and other markets with 110-120v electrical systems.
These pictures above reflect the charging connectors on Models 3 and Y. For Models S and X, the ‘rest of world’ will vary. From 2019, S and X models to ‘rest of world’ had the Menekes type 2 AC plug with 3 phase capability, and are able to use standard Combo-2 chargers with an adapter, or CHAdeMO adapters with a different adapter. There is as Combo-1 to Tesla adapter for Teslas, but this was originally launched in South Korea (the only 240v country using Combo-1) and may not be released for 110-120v countries. Note that the Menekes plug without Combo-2 was used by Tesla in older Tesla vehicles in 240v markets for both AC and high speed DC charging, although this plug does not support DC charging as rapidly as supported by the Combo-2 plug with the 2 extra, larger, pins, as supported by newer Teslas.
Advantages of the Tesla plug are it is smaller than the CCS combo-1 or combo-2 plugs and is, in theory, one system for the globe. However, as the pictures show, even the leading manufacturer with their own chargers does not find one system for the globe workable in practice. The smaller size comes at the cost. The same pins are shared for AC and DC power, complicating circuitry, and there is no dedicated earth as an additional safety, nor provision for three phase AC, which is most useful in countries with 220-240v AC.
Charging at Tesla ‘superchargers’ is mostly at this time available only for Tesla vehicles, even when the plug type is compatible. Special software on the control pins identifies the car to the charger, and currently only Tesla vehicles are permitted, but Tesla has said it plans to open up its charging network, and Aptera already has agreement for use, although their cars are not yet on the market, and it is not like they will use a lot of power.
The Tesla Supercharger network played a fundamental role in making EVs viable in many markets, as at one time, in many countries the Tesla ‘supercharger’ network was, other than charging at home, the first viable charging network. At that start, Teslas own charging was all they needed to think about, so even in countries where Teslas now use CCS-2 or GB/T, the first Teslas sold have Tesla sockets.
Tesla Volts, Amps and Versions.
I will add to this section. There have been suggestions of a single plug for CHAdeMO 3 and CCS2, which could allow cars for all the world but North America and Korea to use a single socket. It would be slightly larger, but if it could be compatible with current CCS-2 combo chargers, then it could be, but currently that does not look simple.
- *2022 September 7: Added Ac charging current control for CCS
- 2021 May 10: Added CHAdeMO3 and other updates.