One Size Fits All: A Combo Plug That Can Handle Fast Charging

By · August 23, 2011

Blink Fast Charger

BP gas stations and others are installing these ECOtality Blink 480-volt fast charging stations, which use the Japanese CHAdeMO standard. (ECOtality photo)

Everybody knows that electric car charging will mostly be done at home with 240-volt Level 2 units in the garage. At best, it’s four hours, and often an all-night plug-in. But public fast charging at 480 volts promises more—a full charge in half an hour. It’s still not a five-minute gas fill-up, but it’s tantalizingly close.

Some 480-volt DC chargers have started to appear as part of federally supported charging programs, and in state highway corridors on the west coast. If battery EVs are ever going to be for more than local transportation, then they'll need quick charging options along major travel routes--hence the Washington and Oregon programs.

The problem is that we’re still arguing about how fast charging is going to work. The process of choosing between the existing Japanese CHAdeMO standard from Tokyo Electric Power and a new made-in-America solution has dragged out beyond the actual rollout of electric cars. And so by default cars like the LEAF (in the SL version) and the 2012 Mitsubishi i have been equipped with CHAdeMO, and Toyota’s Scion iQ is likely to get it, too. On LEAFs with fast charging, there are separate 240- and 480-volt outlets under the nose flap. The Mitsubishis have the outlets on either side of the car.

But now it looks like the American governing body, the Society of Automotive Engineers (SAE), is going the other way and has unveiled a prototype “combo” plug that updates the standard J1772 connector to also include 480-volt fast charging. One plug for all charging. Ultimately, that will prove the right solution—who wants to remember if the fast charging is on the left or right?

SAE Combo Plug

The SAE combo plug.

John Voelcker of Green Car Reports describes the combo plug as looking like a "misshapen football" or something designed to entertain Frankenstein's monster. "Elegant, ain't it?" he asks, before adding, to be fair, that a major benefit is that the 480-volt charging protocols SAE is working on will blend seamlessly with those of the existing J1772.

SAE’s version of the unfolding events is posted here, but it’s pretty technical. This is the upshot: “In the first quarter of next year," the group writes, "SAE plans to establish a standard, integrated coupler that would allow electric vehicles and plug-in hybrid electric vehicles (EVs/PHEVs) to be charged from either a conventional 15-Amp AC wall outlet or a DC connector of up to 90 kW.”

We’re not likely to actually see the production version of the new plug before 2013. Meanwhile, public fast charging is already being installed with the CHAdeMO protocol, and either those expensive units will have to be retrofitted to also include the new combo charging cable or the cars themselves will need a trip to the garage for new receptacles. It’s a bit of a mess that could have been avoided if SAE had included fast charging in the original specs for J1772.

But, given where we are, the integrated one-size-fits-all J1772 is probably the right way to go. There won’t be any guesswork when you’re standing in front of the charging station. In Europe they’ve failed to come up with any common standard, so continental travelers will have to carry a trunk full of adapter cables—just as they have to do for ordinary home outlets (which aren’t standardized, either). One plug, one receptacle, and the car and the charger decide what to do from there. What could be simpler than that?

New to EVs? Start here

  1. Seven Things To Know About Buying a Plug-In Car
    A few simple tips before you visit the dealership.
  2. Incentives for Plug-in Hybrids and Electric Cars
    Take advantage of credits and rebates to reduce EV costs.
  3. Buying Your First Home EV Charger
    You'll want a home charger. Here's how to buy the right one.