Cutting edge lithium ion battery packs being built for the Volt are expensive. Some experts guess they cost up to $10,000 although certainly GM nor their suppliers are saying what the actual numbers will be.

When one looks at the close to $40,000 price tag for the Volt it is recognized that the pack makes up a significant component of that.

But two packs?

GM vice-chairman Bob Lutz recently told Cars.com that the current battery pack prototypes are "performing flawlessly" even in harsh testing environments. He said however that "longevity is the unanswered question".

GM has previously said they expect to warranty the Volt batteries for 10 years/150,000 miles. In this new interview Lutz said "We're being conservative on battery life. For our cost calculations we're assuming each car will need a replacement during the warranty period."

Source ( Cars.com )