Using 100 amp mopar alternator to charge batteries out of a vehicle

I'm using a 100 amp alternator to charge the batteries in a solar panel system that powers my mobile home. I am off-grid, and this is my only source of power in my home. The alternator is run by a 7.5 HP small engine. The alternator/engine setup is for cloudy days. The wiring for the system is all homemade-no car harness involved. I have two questions: I'm using the old Mopar style voltage regulator with the two prong connector. Can I use the regulator designed for the 60-65 amp alternator, or does the 100 amper require a different regulator? Also, does my wiring harness not being balanced have an effect on output? My output used to taper off around 14.5 volts, which was fine. But now its over 15 volts, which is too high for my system. Is there a way to control this, or is my regulator bad, or is it due to an unbalanced wiring harness?