INDIANAPOLIS --- Batteries from EnerDel, a U.S. lithium-ion car battery manufacturer, may power the Fisker Karma plug-in hybrid electric vehicle. 

EnerDel and Fisker Automotive, the independent American carmaker developing a line of high-tech green vehicles, have signed a letter of intent for a potential long-term battery supply agreement. Results of reliability and performance testing will determine a final contract. 

Fisker plans to build 15,000 vehicles per year and market them through an existing network of 32 U.S. retailers. A European retail network will be announced in September at the Frankfurt Motor Show in Germany. 

"EnerDel battery packs for electric vehicles (EVs), hybrid electric vehicles (HEVs) and now plug-in hybrid electrics will help lead the revolution toward mass deployment of electric drive in the United States," said Charles Gassenheimer, chairman and CEO of EnerDel parent company Ener1 Inc.