This is what happens to all trailers after a few years. Many undocumented MODS to deal with...
I would put it back to normal but not remove any of the mod items. I would love to have a second 100AMP ALTERNATOR SETUP in my truck for my additional battery banks if that is what I reading from your comments...
Also you mentioned battery isolator - with todays smart mode charging schemes you cannot use the old DIODE TYPE three port Battery Isolators... The large diodes inside have to much DC VOLTAGE for you to be able to provide the three required charging modes for the additional batteries being 14.4VDC-13.6VDC-13.2VDC.
Todays so-called battery isolators are now accomplished with automatic smart relays that direct connect to the source when needed... Read-up on the BLUE SEA SI-ACR Automatic Charging Relay on-line to see how they provide you charging voltages for additional batteries.
BLUE SEA AUTO CHARGING SMART RELAY SI-ACRMORE INFOWith the cable getting hot sure sounds like a bad wiring concept or batteries wired in the REVERSE ORDER... I think you found the reason it was disconnected.
I would get it all back to normal and then have the experts tell you what you need to do with what you got...
Just my thoughts - not an expert on any of this...
Roy Ken
