DC fast-charging stations greatly increase the convenience of owning an electric car--but they're still far scarcer than slower, 240-volt Level 2 charging sites.

Even where fast-charging stations can be found, there's a three-way split among the CHAdeMO, Combined Charging Standard (CCS), and Tesla Supercharger standards that cuts the number of stations any given vehicle can use.

New data from the most electric-car friendly state in the nation shows that the newest standard, CCS, is roughly two years behind the prevalence of the most common format, CHAdeMO.

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California has the most-developed charging infrastructure of any state, but there's a big gap between CCS and the other standards, according to data from PlugShare provided to Charged EVs.

The Golden State has a zero-emission vehicle mandate that requires automakers to sell a certain number of these models per year.

It also incentives electric cars with cash rebates, solo carpool-lane access, and regulations meant to encourage their use.

Supporting all of those cars--as of March 2015--are 6,597 public Level 2 stations and 652 DC fast-charging stations.

That's about four times as many as the state with the next biggest network, Texas.

PlugShare, which provided and analyzed the numbers from its database of more than 20,000 U.S. charging sites, is the developer of a popular charging-station locator app.

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Out of that total, 324 fast-charging stations use the CHAdeMO standard, 224 are Tesla Supercharger stations, and 104 use the CCS standard.

And while all three standards are growing steadily, CCS now appears to be about as prevalent as the CHAdeMO standardwas two years ago.

Of course, the latter standard did have a head start.

Chevrolet Spark EV at CCS fast charging station in San Diego.

Chevrolet Spark EV at CCS fast charging station in San Diego.

CHAdeMO is preferred by Japanese and Korean carmakers, including the carmaker that's sold more electric cars than anyone: Nissan.

The company began installing fast-charging stations to support its Leaf shortly after the car's December 2010 launch, and has remained committed ever since.

U.S. and German automakers have agreed to support CCS, on the other hand, but so far none has made as large-scale a commitment to expanding the network.

MORE: BMW, VW, And ChargePoint To Build 100 CCS Fast-Charging Sites For Electric Cars

As a step in that direction, BMW and Volkswagen announced earlier this year that they will collaborate with network operator ChargePoint to install more stations.

So far, they've committed to 100 stations on heavily-traveled East and West Coast corridors. Thus far, sales of the bMW i3 and Volkswagen e-Golf electric cars haven't come close to the monthly rate of Leaf sales.

And until the majority of non-Tesla DC fast-charging sites provide recharging on either standard from the same charger, their drivers may have to keep passing by those locations.

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