Electrical problem on Volvo diesel
I recently purchased a 1979 Tolly with twin Volvo TMD40A diesels. When inspecting them I removed the cover on the relay box at the front of the engines and found several wires that had overheated and melted the insulation. The primary one involved runs from the alternator up the the box, through the reset switch and to a relay. I'm going to replace the bad wiring, but I'd be a fool to not discover the cause.
The owner's manual says NOT to use a rapid charger when the alternator is connected to the battery which would be basically all the time. The previous owner installed a Xantrex Truecharge 40 for charging the batteries at dockside and it was not working when I received the boat. I'm wondering if the Xantrex was putting too many amps into the batteries and thus the alternators. It has the ability to direct all 40 amps toward the the low side battery.
I'd appreciate any thoughts anyone has on the issue.
Picture of box below. (Sorry, turned 90 deg left)