Actually there are e-bikes like that. I tested BionX rear engine and it had ability to turn recharge on. also breaks turned the regeneration on. And you really want to train hard you can recharge your battery and pedal. I tested it and let the bike ride freely pretty long down hill, not really steep but still. Speed with full regen 8 km/h.I wish I could have a pound every time I speak to someone about my electric bike when they say "Does it recharge the battery when you go downhill?" everyone I've met on the bike has said that to me.
Thank you. Yes I'm aware that there are bikes like that, the consensus seems to be that they're not worth having. I've never seen any figures on how much power they put back in, it can't be much.Actually there are e-bikes like that.