Moped Army

Think about putting a solar panel on there? Then you could be charging while the bike is locked up at the store, work, wherever.

Also about batteries - a lipo can be charged in an hour. A lot of people like to do it slower to extend the life of the battery or reduce the chance of explosion, but an hour is the bottom line minimum charge time. Also you can have lots of power in a lightweight package IF you are willing to pay for it. I fly electric helicopters for research purposes, the one uses 4 x 8 AH, 18V batteries. Talking amp hours is meaningless without the voltage, its watt hours that matters. Anyway this 32 AH, 576 WH set of batteries weighs something like eight or ten pounds. And can discharge at 25c, thats 200 amps each. But they are not cheap.