My car has KERS braking, dumps the juice back into the battery. I can see it being useful on a bike.
"the rider has to generate the power that charges the bike."
Aided, we presume, by gravity. Using the brakes chucks all that energy away. Stuffing it into a battery, you can get some of it back.
Last edited by snafu22; 11-15-16 at 03:09 AM.