/diy/ - Do It Yourself

If you have a way to stamp disks out of sheet metal you can make a Tesla turbine and hook it up to the shaft of some kind of generator. Just alternate the large disks with smaller spacer disks on the shaft, if that isn't obvious from the picture.

If you want to use an alternator then you can rectify the power and hook it up to a properly rated pwm controller to charge a battery bank.