What I'm trying to say is $1.75 a MOSFET would be a steal, if you could get it. Saw a nice 30mOhm 400V MOSFET. How much each? $28!Am I missing something? I can't see the datasheet. The page shows 59A. I (keep in mind I really don't know what I'm doing since I've never done it before) am looking for something with at least 110A (which I will limit to 70A) capacity so that @125C I can still get the 70A out of it that the legs are rated for. After that requirement, then I would like at least 180 or 200V (leaving room to grow; later if my design works I will be using higher voltage motor) and a low Rds(on). MOSFETs like that can be found, but not for cheap, so I'm in a battle as to if I want to spend the money for the good stuff and blow it up. If I have to skimp on something, I guess it would be voltage; for my lower voltage I might go down to 50V or something; can't see myself going above 50V on a starter motor. I am tracking down several things in parallel. For every mosfet I look at, I also need to figure out what driver to use and I still haven't figured out how to do that.
You'll need a high voltage driver, like IR2110, which has a built-in 500V driver.