Wheels Blog: G.M. and BMW Adopt D.C. Electric Car Charging

General Motors G.M. and BMW have adopted a new charging standard, and other manufacturers are expected to follow.

General Motors and BMW say they are moving ahead with technology that can give electric cars an 80 percent charge in 20 minutes. Charging time is a major problem in a car that can travel only 100 miles or less between charges.

Today, electric cars almost always use the existing alternating current power grid for charging, which means that the energy must first be converted from A.C. back into the D.C. format car batteries use to store energy. Bypassing the on-board hardware that does that conversion means avoiding a bottleneck and reducing charging time.

G.M.’s Chevrolet Spark EV, based on a Korean-built gas-powered minicar, has a published range of 82 miles. BMW says its i3 will go 80 to 100 miles on a charge. If either one could take on an 80 percent charge in 20 minutes, and if such charging stations were widely available, it could effectively multiply the car’s daily range.

G.M. had previously announced that its Spark would have a charging port with inputs for the standard A.C. charger or D.C. equipment.

The two vehicles will use a standard recently established by the Society of Automotive Engineers. There is an older international standard, widely used in Japan, but D.C. charging in North America is a rarity and companies here are starting fresh. Along with G.M. and BMW, other companies that have promised to use the new S.A.E. standard are Ford, Chrysler, Daimler, Volkswagen, Audi and Porsche.

G.M. and BMW said in a joint announcement on Tuesday that after several days of testing, they were confident that a charger using the S.A.E. standard would provide an 80 percent charge in about 20 minutes. There is a catch, though: Vendors have to buy the chargers and install them somewhere. General Motors says chargers will cost from $20,000 to $30,000 each.

General Motors G.M. says the D.C. charger will allow an 80 percent charge within 20 minutes.

How could a charging station owner make money on that? In general, a driver would be buying a quantity of electricity for which a homeowner would pay about $2, but the D.C. power could be priced higher, like the difference in price between a six-pack of soda on a supermarket shelf and a single bottle in the refrigerator next to the cashier. Form may matter as much as quantity.

Or it could be a loss-leader. Heather Rosenker, a spokeswoman for G.M., said that the D.C. charger “could be owned by the utility or the business in which it is housed (i.e. a restaurant, hotel, shopping center, etc.).’’

In a conference call with reporters on Tuesday, David Danielson, assistant secretary for Energy Efficiency and Renewable Energy for the federal Energy Department, acknowledged that “the cost of those quick chargers can be up there.” He said that the government was working to bring down the price of the electronics involved.

Mr. Danielson was promoting a new Web site called eGallon, which compares the cost of gasoline with the cost of the electricity that will take a car the same distance. The site assumes the car will go about three miles on a kilowatt-hour and calculates that, while gasoline is on average about $3.65 a gallon, the eGallon cost would be $1.14. But the eGallon calculator compares the cost of gasoline with residential electricity rates and does not make any allowance for an electricity mark-up a vendor would use to earn a profit on the charging equipment.

According to a news release from General Motors, the direct current fast charging option should be available sometime after the Spark EV becomes available in California and Oregon this year.