Toyota dealerships in four U.S. metropolitan areas are offering to convert customers' Priuses into plug-in hybrids, using technology from the battery maker A123 Systems.
The arrangement provides the strongest indication yet that lithium-ion battery technology is ready for mainstream automotive use.
A123, of suburban Boston, is among the four battery companies General Motors is considering to supply the Chevrolet Volt. GM wants the plug-in hybrid car on the market in 2010.
Lithium-ion batteries are seen as key to electrification of the automobile. The industry is debating whether the batteries can withstand mass production and daily use by motorists.
The Tesla Roadster, an all-electric $100,000 car that uses lithium-ion batteries, is on sale. But it is widely viewed as an expensive exotic vehicle for a few enthusiasts.
About 600,000 Priuses are on U.S. highways. The hybrid car's base sticker price is $22,160, including shipping.
How many Prius owners will spend $10,000 to convert the cars to plug-in power is unknown. A123 wants Congress to provide a tax credit of $2,500 to $3,000 to Prius owners who make the conversion.
Leslie Goldman, an attorney who represents A123 in Washington, said more than 1,000 Prius owners are on a waiting list for the conversion.
The technology "is ready for prime time," said Goldman, who has been driving a converted Prius prototype for about 18 months.
Felix Kramer, an expert on plug-in hybrids, said he believes the A123 conversion will perform satisfactorily. It uses lithium-phosphate, which does not have the same risk of overheating and exploding as some other lithium chemistries, Kramer said.
A123 does not want to jeopardize its future business supplying batteries to automakers for new vehicles, added Kramer, founder of the California Cars Initiative.
Toyota is unhappy about the conversions but said its dealerships are independent businesses that can do what they want.
Still, Toyota said its owners should not modify "any of our vehicles," hybrid or otherwise, said Bill Kwong, a spokesman for Toyota Motor Sales U.S.A. Inc.
Changes could void factory warranties, Kwong said. A123 offers its own warranty on the conversion.
Toyota dealerships that offer the conversion are Westboro Toyota, near Boston; Fitzgerald Toyota, near Washington; Toyota of Hollywood, near Los Angeles; and Denny Hecker Automotive Group, near Minneapolis.
A123 also has certified shops in Seattle and San Francisco to offer the conversions.
