so it must be recharging itself ?,(reply>), @Magic Mike yes, however a dynamo requires someone or something to move a magnet through the coil of copper wire. So, the batteries could be charged this way but again the batteries can't or rather wouldn't be charging themselves.,(reply>), @the screen troll ever heard of a dynamo ?,(reply>), Scientifically impossible. If they were recharging themselves they would be a perpetual motion machine and that can not exist the laws of thermodynamics says so. Plus the energy to recharge itself would make it lose energy in heat so it would be more efficient to make the battery just ring the bell rather than make it also recharge itself.,(reply>), No