Good points on the battery. and that's probably the focus of "longterm costs" folk seem concerned about?

There's a big difference when the battery is being managed by computer and charged as needed from a power source like regen braking or an engine to keep it in the sweet spot. You've probably also noticed that the battery is not used nor charged until it's heated up to some defined operating temperature, in the HAH? Unlike a camera or latop which doesn't have much choice!

Take with a BIG grain of salt, but I've read on the 'net that:

a) There are 8 year old Prius's in Japan that haven't had batteries replaced ( the model was released long before it reached our shores ). In fact, a statement was made that *no* battery set in any existing Prius has required replacement yet, other than due to accidents. ( Anyone know of any? )

b) Projections indicate they should last well over 10 years, which is why the manufacturers met California's warranty requirements. One site that indicated their engineers said an upper end of 15years may be realized... but they really don't know yet... just not enough empirical data beyond the Prius's mentioned in (a).

c) Comparisons with older electric cars' battery life are also not valid, since they didn't have the software management that the newer systems have.

d) Apparently there was a IEEE article on the subject of battery life in hybrids... anyone have a link or synopsis?

Cheers