[modmonster]

thats a cool idea. would be good if you could make it suck enough power out of the vechicles momentum to slow it down to a stop. maybe a standard alternator could be geared up to produce a higher voltage/amps. you would probably need to find the most powerful alternator you can find as the power involved in stoping a vehicle is large and might melt a regular motor/alternator. it would be easy to cut the electrical load when braking is not required -the easiest way to control it.

high charging amps are not ideal for lead batteries though.