You sure?, I mean the ohm's law thingy says that 13.8v and 40amps is 552watts. I dont know what to do i can get the amp and watt ratings it calls for but not quite the voltage. Maybe i should do a 24v battery setup and just buy a charger for them, 2 12v batteries aren't exactly portable. I'm assuming that i would have to have some pretty high mah 12v's am i correct?