1935 John Deere hit and miss DC generator proof of concept. I used a free treadmill motor rated at 15 amps and 90VDC. It needs a new pulley, the correct belt and probably a belt tensioner. This was something I just threw together to see if it would work.
This would do really well with a charge controller and a deep cycle battery. The hit and miss will run for hours on minimal fuel making it a great candidate for a backup solar bank charger in case you have too many cloudy days.