All Cars, All the Time

Where's That Eveready Cat When You Need Him? Plug in Hybrids Need More Lives?


A recent Road & Track article brought up an interesting point about plug-in hybrids. Plug-in hybrids have generated a lot of positive ink because of the possibility that drivers could, if they have relatively short commute, use electric drive for most of their commute. Thusly a plug-in hybrid would get about twice the fuel economy of a regular hybrid car. R&T’s article questioned what plug-in hybrids might do to the life of a hybrid car’s batteries. Toyota currently estimates that its hybrids’ batteries will last for the design life of the car or about 150,000 miles. This assumption is based on the fact that the battery pack is running at 60 percent charge +/- 10 percent. However, a plug-in hybrid would greatly stretch that range from the bottom to the top to get those high mileage numbers. Unfortunately most of the chemical stress placed on a battery occurs in the last 20 percent before full discharge and at the top 20 percent of full recharge. Barring a major advancement in battery technology, plug-in hybrids would see a shortened lifespan for their batteries. How much shorter? That remains to be seen. Plug-ins could still very well make sense, but it’s just an interesting observation that it’s not all wine and roses.