The batteries in the Civic, and all Hybrids to date are Nickel Metal Hydride, not Lithium Ion. I believe they experience a far more gradual failure pattern then Li-Ion. I believe a key to the battery life is that the car never allows the battery's charge to get much less than 50%, unlike your cell-phone battery. Honda's website simply says that the batteries are made to last 10 years under normal driving. Toyota has extensively tested there batteries to 180,000 miles and have only shown slight losses in power. You can bet that if Honda is offering an 80,000 mile warranty, they expect them to last far longer.

I believe the batteries currently run in the $3000 range, but this should fall considerably in several years as quantities are increasing. There are a few Insight owners here who have experienced failure long after the warranty was up, and Honda still paid for most of the cost as a PR move. Insights have been around for 6 years and have similar but older drivetrains to the Civic, so you can learn a lot about what to expect with high mileage on Insight forums.


As far as your thinking that the Civic battery will experience less wear because it offers less assistance, I'm not sure I agree. The Civic's IMA system does provide less assistance, but the battery and motor are smaller, and thus likely works just as hard as the Prius's.


Good luck with your decision. How many miles per year do you routinely drive?