So I am in the beginning stages of considering the PIP. I am of the ilk that buys cars new and runs them for 15 years. So the life of the PIP battery is a primary concern to me. Toyota says the PIP battery is 4.4 kWh Lithium-Ion (not sure the exact chemistry). Users say it takes 3 kWh per charge. That is 68% of full charge so it sounds like Toyota has program the thing to run from 84% to 16% or something like that. Question: If I am cycling this battery 2x per day, living in the Boston area (not too hot or cold), how long is it reasonable to expect this battery to last? It needs to give 11,000 cycles over the 15 years of ownership. Will it follow the degradation that Nissan claims the for the leaf: 80% after 5 years, 70% after 10 years . . . 12 years? 15 years? My commute is between 11 and 17 miles depending on route and stops. I am thinking with HM techniques I could get to work, charge, and get home all EV. If the battery stays strong I will make my additional investment over the regular Prius back no problem. As the battery degrades down to the 70% range all-EV won't always be possible making the vehicle a bit less compelling. Thoughts? EDIT: Assume 12,000 miles per year, 2/3 EV and 1/3 HEV.