Why Can't Electric Cars Recharge Themselves?

Christine and Scott, I have a question about the power supply for electric cars. I was reading recently that the plug-in hybrid could have exceptional gas mileage, up to 600 if memory serves, but would have to be plugged in overnight to recharge the battery. I don't understand why an electric car needs to be plugged in to recharge. We have had alternators and voltage regulators in vehicles for years. Why can't someone develop one capable of recharging the battery pack in an electric car so that it doesn't have to be plugged in? Perhaps I'm looking at it too simply. If so, please advise why. Thanks in advance. Bill

Hi Bill,
You’re not looking at it too simply at all--it’s a good question. We love readers with inquisitive minds, and the answer to your wonderment is basic physics. In regular cars, and even in normal hybrids--to a lesser, but similar, degree--the internal combustion engine drives the alternator/generator to keep the battery charged. This works well for two reasons: the engine is already running to keep the car moving, so it’s also available to power the alternator, plus these relatively small starter batteries don’t require much power to keep them charged, so the alternator load is light. However, in pure electric cars ...

Want to read the whole deal on what's up with electric cars and recharging? Check out Bill's letter, along with our answer to get the scoop on the recharging issue of plug-in electric cars. --Christine & Scott

photo © General Motors - Chevy Volt electric car