[bucknmusky]

Since most of us are modding gasoline power cars or replacing gas engines with elec motors and batteries I had this concept. If it has already been invented please let me know where to get one, if not someone here should get on this and the profits are all yours.

Concept: traditional front wheel drive gas powered car has a rear axle which is really nothing more than a trailer axle. Small lightweight cars on the highway only need to overcome air and rolling resistance to move along at cruising speed so horsepower required is low, especially in well areomodded cars.

Replace the rear axle with either 2 motors, one mounted on each reat axle shaft (imagine the rear axle from an S-10) or one large motor mounted where a traditional driveshaft would enter the reat differential. This motor could even be mounted vertially as to put the motor in the trunk to reduce the amount of junk hanging below the vehicle.
place batteries in the car trunk to power the rear electric drive, use regen braking to recharge (maybe)

Car could be run in either mode by putting the front or rear systems in neutral and driving off your choice of power. using a plug in system at home and making short trips you may never have to run the gas motor. Since city driving kills overall mpg you could use elec mode for getting through the city and once on the freeway on ramp switch to gas power where your gas engine, geared high and run at constant speed would be more efficient and have all elec needs fed off of batteries (water pump, power steering) so the engine could be just for driving.

But for now lets start with the rear axle swap out could be just a bolt on system for most small cars, with a battery bank in the trunk, of course Ni-Cd or LiH batteries would be best for weight but the cost factor is still high.