if you want to charge batteries you could change out one of the alternators for a big one like the competition car stereo guys use . some of them install 4-370 amp alternators in there vehicles and huge battery banks to power there systems. then there is the cb radio guys that do the same and blow the belt off the alternators when they key the microphone. lots of videos on you tube of these guys. depends on how much you want to spend. you don't have to go that far but the possibilities are endless.
mechman alternators