I had it on a 12V. A standard convertor is fine. I had a supertight convertor on it, that would go to about 12-1300 and it struggled to spool it while holding the brakes. I then put in a looser convertor that woudl allow about 1500-1600 rpm on the brakes and it would spool well. Pretty much about 1700-1800 it is gone like a rocket.