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Fast Charging makes electric cars more useful because of the reassurance drivers get knowing they can quickly recharge, and the faster effective trip speed. It seems that car owners with fast-charge capable cars, with enough fast charging stations around them, feel capable of taking longer trips.
While fast charging is often unnecessary , because the optimum charging rate varies depending on the usage scenario the driver currently faces, it sure is convenient that fast charging stations give an almost complete recharge in under an hour. Unlike cars with 6 kiloWatt level 2 charging systems (20-25 miles of range per hour of charging), fast charging’s faster charge rate (50 kiloWatts or more) can supply 100 or more miles of range per hour of charging. A significant fast charging network available should make electric cars more attractive than otherwise, and lead to higher adoption rates.
In some cases it means electric car drivers can take real road trips — blowing up one of the negative electric car stereotypes. (like being be limited to driving a short distance from your home)
Unfortunately, while fast charging electric cars were available in 2011 (Nissan Leaf, Mitsubishi i-MiEV), CHAdeMO charging infrastructure didn’t grow very fast. Some automakers lobbied against CHAdeMO deployment because it wasn’t an SAE-blessed standard. Instead the CHAdeMO was standard co-developed by TEPCO and the Japanese automakers. Instead of adopting CHAdeMO, the SAE developed their own fast charging standard (Combo Charging System), Tesla Motors developed a proprietary fast charging system (Supercharger), and the Chinese developed a different fast charging standard.
The resulting effects were that
- Fast charging adoption happened more slowly that it might have
- Perhaps, Electric car adoption was delayed because of slow fast charging infrastructure build-out
- As of 2015 there are three (or four) fast charging standards in various stages of adoption, causing a certain amount of pain to electric car drivers – we can’t just go to the closest fast charge station, we have to find the one that’s compatible with our car
What we have in 2015 is a multi-way electric car fast charging standards battle. Consumers are caught in the middle not knowing which fast charging standard to support, not knowing enough to know how to choose between them. Fortunately some of the automakers appear to be acting to soften the pain of incompatible fast charging standards by deploying multi-protocol fast charging stations.
What we deserve is ubiquitous fast charging stations with a unified fast charging protocol. Our gasoline powered brethren have a unified standard for gasoline pump nozzles, we deserve the same for fast charging.
With multiple competing fast charging standards adapters would be a useful product, to enable fast charging from an otherwise incompatible charging station. While Tesla Motors is selling a CHAdeMO-to-Tesla adapter, it seems such adapters might have limited popularity due to expense and deployment of dual-protocol charging stations.
Charging Level & Effective Trip Speed
Before we get into the fast charging standards, let’s do a small review of why this is important and some terminology.
DC Fast Charging is the fastest (highest powered) electric car charging system currently available. The charging station provides a high power DC current, as much as 120 kiloWatts, to the car’s battery pack bypassing any other charging equipment in the car.
Some people call this “Level 3” because the normal-speed charging generally used (240 volt AC at about 30 amps) is popularly called “Level 2”. Both names are incorrect.
What’s popularly called “Level 2” is actually called “AC Level 2” and covers single phase AC charging at up to 20 kiloWatts in power. In practice the highest rate currently supported by electric cars is about 10 kiloWatts, but the public charging network generally only supports 6 kiloWatts.
The DC Fast Charging we’re talking about is not “Level 3” but “DC Level 2” at power rates up to about 90 kiloWatts.
Where this becomes important is the recharge times noted in the chart. The higher the charging power, the more quickly the car can be recharged. Put another way, high power charging makes for a faster effective trip speed – because you gain more hours of range per hour of charging. See Electric car charging rates, how fast, how slow, what we need, and why for more information.
- 6 kiloWatts: 20-25 miles range per hour of charging (typical AC Level 2)
- 50 kiloWatts: 120ish miles range per hour of charging (CHAdeMO, CCS)
- 120 kiloWatts: 300ish miles range per hour of charging (Tesla Supercharger)
Taking a road trip with an electric car would be much more pleasant with 300+ miles range per hour of charging than 20 miles of range.
DC Fast charging standards – CHAdeMO, CCS, Supercharger, China
There are four or so DC Fast Charging systems currently being used by electric car manufacturers. The picture shown here has four different connectors without even accounting for the Tesla Supercharger because there are two variants of the ComboChargingSystem charging socket.
At the current moment the leading car for each type is:
- CHAdeMO – Nissan Leaf
- CCS – BMW i3
- Supercharger – Tesla Model S
- China GB/T – ?
Let’s take a look at each.
CHAdeMO – (Nissan, Mitsubishi, Kia)
CHAdeMO Plug – Source:http://en.wikipedia.org/wiki/File:CHAdeMO_Plug_VacavilleDavisStDC2.jpg
CHAdeMO is the trade name of a quick charging method for battery electric vehicles delivering up to 62.5 kW of high-voltage direct current via a special electrical connector. It is proposed as a global industry standard by an association of the same name.
It was defined by the CHAdeMO Association – Purpose/focus CHAdeMO Association aims to increase quick-charger installations worldwide and to standardize how to charge the vehicles. – http://chademo.com
– CHAdeMO was formed by The Tokyo Electric Power Company, Nissan, Mitsubishi and Fuji Heavy Industries (the manufacturer of Subaru vehicles). Toyota later joined as its fifth executive member. CHAdeMO is an abbreviation of “CHArge de MOve”, equivalent to “charge for moving”. The name is a pun for “O cha demo ikaga desuka” in Japanese, translating to English as “How about some tea?”, referring to the time it would take to charge a car.
CHAdeMO is a form of DC Fast Charge, for high-voltage (up to 500 VDC) high-current (125 A) automotive fast charging via a JARI DC fast charge connector. The connector is specified by the JEVS (Japan Electric Vehicle Standard) G105-1993 from the Japan Automobile Research Institute. The connector includes two large pins for DC power, plus other pins to carry CAN-BUS connections.
Because CHAdeMO ports do not support AC charging, cars must have two charging ports – one for AC Level 2, the other for CHAdeMO.
AE Combo Charging System (CCS) – (BMW, GM, VW, and other carmakers)
When tasked with developing a fast charging system, the SAE J1772 committee basically took the existing J1772 plug and added on two large pins for high power DC. The upper part is the ordinary J1772 plug used in the USA, and the lower portion are the two DC power pins.
Among the reasons the J1772 committee developed CCS are
- Single charging inlet to support slow and fast charging (versus two required for CHAdeMO)
- Use smart grid protocols to control charging
- Same connector serves multiple purposes
The first point allows car makers more design freedom by requiring only a single hole in the skin of the car (or, a smaller hole) for recharging. The charging cord is also lighter weight than the CHAdeMO, and easier to use.
The second point – see the image above labeled “IEC DC Charging Systems” – has to do with the control protocol between the car and the charging station. We’ll discuss this below, but CCS uses PLC for that communication, whereas CHAdeMO uses CAN. CAN is a data protocol used between components inside cars, while PLC is part of the smart grid protocols.
Tesla Supercharger
- The Tesla mobile charging unit comes with adapters for every kind of power outlet, from 120 volt 12 amp (NEMA 5-20), through to 240 volt 50 amp (NEMA 14-50).
- Via an adapter, it can connect to J1772 charging stations
- At a Supercharger station (pictured above) it can receive DC fast charging at up to a 120 kiloWatt rate
It means a Tesla Model S or Model X owner can get rapid charging in a wide range of situations.
Tesla Motors also sells an add-on adapter allowing a Model S/X owner to recharge at a CHAdeMO station. Tesla Motors does not sell any kind of adapter allowing owners of CHAdeMO or CCS cars to recharge at a Supercharger station, however.