Well the answer is I don't know?? I have a 6 hp Briggs n Stratton lawn mower motor rigged up to turn the 600 amp catapiller alt running to 2 tractor batts. I am using a boss 5k amp (yeah right) running in 1/2 ohm pushing 4 crappy subs. When I burp it it pulls the moter down a bit but not drastically. We are still having trouble with the voltage staying constant at 15v. It's only a matter of time before I get it right. I think it's gonna work I just want to get it working reliably before I try it on a high current amp. But soon I will have a 600 amp 24 volt alt with little to no ampreage drop under heavy loads.