An advantage gasoline car drivers enjoy is that gasoline nozzles are the same at every gas station. Gasoline can be purchased at any station, and there's no worry over whether the nozzle is compatible with the car. The only variation in nozzle shape is for functional purposes – you don’t want to put diesel fuel in a gasoline vehicle, and vice versa. Therefore gasoline and diesel nozzle shapes are incompatible.
In electric car charging, Level 2 AC charging uses a common protocol (J1772) and a common connector shape. For Level 2 AC charging, we can drive up to any charging station, plug in, and get a charge.
Unfortunately, DC Fast Charging does not have such a simple story. There are three competing DC Fast Charging standards, making a problem for EV owners. They need to know whether their car supports fast charging, and which stations it is compatible with.
A similar problem exists for portable electronics gizmos. Each manufacturer has chosen differently shaped charging ports, making it impossible to mix-and-match chargers. If you lose your electric razor charging cord you might have to throw out the old razor and buy a new one because of the difficulty to replace the cord. A common standard for electronic gizmo charging cords would mean a market could spring up for 3rd party charging cords. That’s happened in part with the adoption of USB as a charging cord, since such devices can be powered over USB. Some locales even require a USB3 variant as the standardized portable electronics charging cord.
In an electric car we want the freedom to drive up to any electric car charging station and plug in. There shouldn’t be any required adapter cords, no worries about incompatible charging plugs. The phrase “plug-and-play” is the operative word.
This hasn’t always been the case for electric cars. The previous phase of electric cars – late 1990’s to early 2000’s – saw two competing electric car charging standards. One used a claw shaped ungainly charging plug whose signaling system formed the basis of the J1772 charging standard. The other used a flat paddle which charged via an inductive connection.
It meant that at every charging station installation half the stations used the claw connector and the other half used the paddle connector. Which meant the macro-economic budget for charging stations was needlessly split between claw and paddle charging.
There’s a phrase — “All the wood behind one arrow” — which means focusing all resources on one goal. Having multiple charging standards is the opposite, splitting the resources among competing goals. Instead of resources being focused on one goal — building out a cohesive charging station network that everyone can use equally — they’re split into parallel efforts where the car makers fight each other over the best charging standard and the customer loses out.
Since that earlier electric car phase a common charging standard was developed for level 2 charging – J1772. The typical station runs at a 6 kiloWatts charging rate, and there are charging stations available from many vendors. They all have the same charging plug, and all the electric cars have the same charging socket.
It means we can go to any level 2 charging station and charge. That’s the power of unity, and is very convenient.
Well, except for one thing, and that’s the requirement in most cases to have a membership card with the charging network operator. Having a common charging plug puts all the wood behind one arrow. But this membership card requirement creates a small bit of fracturing in the market. One has to acquire and carry around cards from every charging network operator.
Unfortunately the DC Fast Charging market doesn’t enjoy the unity of a single standard.
Instead of one fast charging standard, there are three (four if you count China). See EV DC Fast Charging standards – CHAdeMO, CCS, SAE Combo, Tesla Supercharger, etc
The multiple standards (CHAdeMO, Combo Charging System, Tesla Supercharger, and China GB/T) mean we can't drive up to any DC charging station and charge. We have to know not only the network ownership of the station, but whether its charging connector is compatible with our car.
At the macro-economic level it’s a misallocation of resources. The incompatible charging networks mean duplication of equipment and services. For example, the Supercharger network build-out is excellently serving owners of Tesla’s automobiles. It encourages sales of Tesla automobiles, because of the Supercharger network. But this doesn't help the overall project of electric vehicle adoption, because no other car brands can use the Supercharger network. All the wood is NOT behind one arrow, but is behind 3-4 competing arrows.
There's a small degree of cohesion in the DC Fast Charging market. The "dual protocol" stations support both CHAdeMO and CCS, giving us a small degree of assurance that we can charge at any given station.
What’s needed is to get past this phase of incompatible fast charging standards. At the big scale, we need all fast charging stations to "speak" one charging protocol. What’s needed is putting the resources behind fast charging into building a cohesive network that supports us all. This byzantine matrix of competing fast charging standards serves no-one.