Hello! this is my first post here,hope it's the good part of the forum. I have some questions and i would appreciate it very much if someone more knowledgeable than me could help me out. A while ago I saw a radio that was used without batteries,you had a wheel and you just had to spin it like a bicycle pedal,over and over,until it got enough energy to work.I got an idea to build something similar but I don't know the science behind it.(there are still a lot of things i need to figure out,but i love a challenge) Could someone give me some numbers,how much should i have to spin to produce enough current for the battery? How many watts or kilowatts would that produce an hour?Could i pedal very hard to recharge it faster or do i need a constant speed?I have standard 12volt rechargeable batteries and an accumulator(i think it's called than in English,I am not sure). If someone could give me some numbers on how this could work or other tips/insight I would be very grateful,thanks for reading and have a nice day!