Originally Posted by cyccommute

I’m not sure what you are looking for in a “true” super capacitor but it would still be a chemical battery. That’s all that super capacitors are. They use electrodes and electrolytes to store energy in a chemical form. They just happen to be able to be charged and discharged more quickly than other batteries. There is nothing magic about them.

As to regenerative charging, yes, it had been around for a very long time. It is a bit of a flim flam, however. It can take some of the momentum of the vehicle and convert it into stored energy but not all of it. It also only gives back a portion of the energy as useable power. But the First Law of Thermodynamics says that the change in energy is equal to the heat added to the system minus the work done by the system. In less technical terms, if you put a certain amount of heat…in this case…electrons into the system, you can’t get back that same amount of electrons because some of the inputted energy is lost to work. In the case of regenerative braking, you will not gain back all the momentum of the vehicle as electrical energy because some of it is lost through the work of stopping the bike. There is no free lunch.

As others have pointed out, a bicycle is pretty small and light. There’s not a lot of energy to get back and you are losing a fair amount of that energy. The supercapacitor also has its inefficiencies…both going in and coming out. The mechanism for regenerative braking would also add losses to the bike in both complexity and weight.