Rubbee consists of a polyurethane roller wired to a 14.4-volt battery pack. The doohickey presses the roller against the back tire of the bike, propelling it with the force of wheel-on-wheel friction ...
[Tom Stanton] wanted to see if supercaps have any practical use on e-bikes, and built a DIY electric motor in the process. One of the problems with supercaps is the rapid voltage drop during ...