I would recommend reading the Dept of Energy studies:

http://www1.eere.energy.gov/vehicles...d_library.html

What they found was after 160,000 miles, the Prius batteries had gone from 6.5 Ahr to 2.5 Ahr. Yet even with this decline in capacity, the vehicles were still getting nearly the same mileage at the end as at the beginning of the tests:
http://www1.eere.energy.gov/vehicles...ife_test_1.pdf

I've got four from another Prius salvage and they all measured 3.3 Ahr. This weekend, I'll pickup up a failed battery pack, two know failed cell assemblies, and will begin testing those cells. I'll also do a failure analysis of the two failed packs.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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