Me and some friends are working on an invention right now but we need to know what is the best way to make alot if electricity, that can be transfered to a recharable battery. no energy from power outlets. it also has to be pretty small about the size of a penny to the circumferece of a quarter. it has to be able to generate electricity for long periods of time. right now were thinking of magenets encased in a copper or gold gyro. please post ideas.