Range extension for electric vehicles

When electric vehicles are discussed with the public, two questions inevitably arise: how far can it go between charges, and how fast can it go? Both of these issues are related in part to the electrical energy stored and the efficiency of conversion from electrical energy to mechanical energy. In practical use many electric vehicle drivers have been known to use only 10-20% of the vehicle's range before recharging. The desire not to run out of enough energy to return to a charging station motivates the drivers to be very conservative. One solution to this problem is to equip the vehicle with an auxiliary power supply which will recharge the batteries. Such vehicles are powered by a combination of stored electric energy and chemical fuel. Here, the author describes these so-called hybrid vehicles.