No Fast-Charging for Volt as GM Questions Need

The modern age of electric vehicles has arrived, but that doesn't mean high-voltage charging stations need to be as prevalent as gasoline stations today, a General Motors Co. executive says on the sidelines of the Los Angeles auto show.

Buyers of new electric vehicles have three charging options: Plug into a standard 120V wall socket, which takes about 20 hours for a full charge, or a dedicated Level II charging station operating at 240V capacity, which can do the job in less than half the time.

Lastly, high-powered 480V DC fast chargers are being installed across the country, supported by U.S. Department of Energy grants intended to foster establishment of an EV infrastructure.

These devices can charge an EV in about 30 minutes, providing a security blanket for buyers of all-electric vehicles, such as the Nissan Leaf, that lack gasoline engines to keep the wheels turning when the electricity runs out.

GM's Chevrolet Volt has a gasoline engine to power a generator to run the vehicle when the battery's charge has been depleted. But it was designed specifically not to accommodate a 480V fast charge, says Britta Gross, director-GM's Global Energy Systems & Infrastructure Commercialization unit.

“The goal was to make the Volt as invisible to the (electrical) grid as possible,” Gross tells Ward's. The Volt plugs into a standard household outlet and also can use a 240V dedicated charging station.

In illustrating that impact on the grid, Gross says a 120V wall socket with a capacity of 12 amps allows 1,100 watts for charging. But a DC fast charger has a capacity of 100 amps, allowing 50,000 watts of power to surge into the battery.

Repeated cycles with these high-output devices will impact battery life, Gross says.

Gross also has cost concerns about fast chargers. The docks are at least $30,000 apiece, and installation adds another $15,000 to the tab. Supplier Eaton Corp. says its 480V EV Quick Charger will go on the market in early 2011 with an MSRP of $64,000, plus installation. “Someone's got to pay for that,” Gross says.

By comparison, a 240V charging dock, smaller than a laundry basket and designed by GM, is available to Volt buyers from SPX Service Solutions, priced at $490. Home installation will cost about $1,500.