Electromagnetic Battery Charger
On an electric powered car, make the drive shaft(s) into high power electromagnetic battery chargers. While driving on one set of batteries in the front of the car, the batteries are being charged in the back of the car. When the batteries in the front of the car are depleted, switch over to the batteries in the back of the car while the ones in the front charge. Add in a computer controlled circuit for switching circuits on the batteries.
Reward: Get one of the cars for free