After much badgering by DIYers and energy activists, Toyota relented and built a plug-in version of its Prius hybrid, showing it off at the 2008 Paris Motor Show. Noting that the Prius' hybrid system let it run on electricity only during low speed driving, a few DIYers hacked their Priuses to run longer and at higher speeds on electricity, keeping the batteries charged by plugging them in overnight and achieving over 100 mpg in some cases. For a long time, Toyota refused to acknowledge the benefits of plugging in, but now has seen the light, sort of.
The plug-in Prius at the show uses an expanded battery pack, but Toyota sticks with the car's standard nickel-hydride batteries. The people who have created their own plug-in Priuses use batteries that can stand a deeper discharge. But where most electric cars take 4 to 8 hours of charging, this plug-in Prius gets a full recharge in an hour and a half. The downside? Its electric-only range is just a little over six miles. Toyota claims that in Europe, most car trips are less than six miles, so that plug-in Prius drivers will infrequently have to buy gas. Toyota intends to market a plug-in hybrid in 2010, and is currently testing different configurations in the U.S. and Europe.