0orksecurity 11 years ago If you're using a motor as a generator, it's probably putting out pulsed DC. If so, you can put that through a transformer. If you're actually getting steady voltage, look up the circuit diagram for a DC-to-DC converter (basically an oscillator feeding a transformer feeding a rectifier feeding a regulator). Caveat: Nothing is free. If you increase the voltage, you're going to decrease the current. (power in watts is volts times amps, and in fact you're probably going to lose some wattage in the process of doing the conversion). So you may or may not actually get enough 14V power out of this to make it worth the effort. Do the math and figure out how long it's going to take you to charge the batteries with that much power.