I am trying to figure out whether I can use a small Minn Kota trolling motor as an electric generator. If I add a 10" prop the max energy from the water passing the prop should be about 700W and if the prop is 50% efficient, it should put half of that on the shaft. I expect the prop to turn about 600 to 1200 rpm. Can I use the standard Minn Kota motor if it runs 1800 rpm unloaded at 12.8V? I expect it will need to turn more than 2000rpm to generate 12V. Is that correct? In other words: if a motor needs Y volts to achieve X rpm, does that also mean it will need at least X rpm to achieve Y volts?