1984 ford E350 turtle top Van Terra or Terra Vn

I posted this before so I'm sorry if you have already read this. I recently bought this MH. It had a fuel problem and I was able to take care of that. Now I have a charging issue. The previous owner told me that he had problems but the way he was talking it sounded like the problem had been taken care of. Any way the next day after I get it home I pop the hood and their is battery acid everywhere under the hood. So I check the charging output this thing is charging at 20.6 volts the battery is swelled up the caps are almost all the way off. After further checking someone had jumped 12 volts to the field on the alternator on top of having the original wires from the voltage regulator going to the alternator. So not wanting to have any problems with this issue any longer I replaced the voltage regulator and cut the wire that was jumped to the field of the alternator. Now my needle on the charging gauge violently sweeps back and forth and the lights surge with the needle sweeps. I replaced the regulator again and the alternator this did not change anything. Someone said that the house battery may be dead I charged it this did nothing as well. I removed the regulator cleaned all grease, dirt and paint from behind the regulator and remounted still no good. Removed the wiring harness and remade all connections this did nothing finally pulled the dash checked the gauge it checked good. I isolated the house battery from the starting battery this didn't help. I pulled all fuses this didn't change anything pulled all fuses from the invertor and also turned off all breakers still nothing. So any help would be appreciated. Also put a new battery in as well.