06-12-2017, 09:33 PM
Without a wiring diagram that may be difficult to diagnose. Seems to me If your entire 12v electrical system is dropping offline (house and start banks) I would start by looking at the groundIng wires coming off the batteries. If the problem were on your +12v side it would show up only on that one bank (house or start) so I would be looking at the common wires that are shared across both banks (ground).
More than likely all your batt grounds are strapped together and then go to a bus bar, engines, etc. A bad connection or wire can create a lot of resistance and sometimes act like a switch when batt voltage drops (say after starting an engine) or when the connection gets hot. And that will definitely affect both 12v systems/circuits.
You may want to put your volt meter on a good +12V source then move the black lead across the battery grounds and then the bus bar. Do the test wih the batt charger off and look for a voltage drop at one of the terminals. a resistance test across each ground wire may also help as will an IR thermometer after pulling a good load (again with batt charger off)
Some others on the forum may be able to offer better advice. Good luck.
More than likely all your batt grounds are strapped together and then go to a bus bar, engines, etc. A bad connection or wire can create a lot of resistance and sometimes act like a switch when batt voltage drops (say after starting an engine) or when the connection gets hot. And that will definitely affect both 12v systems/circuits.
You may want to put your volt meter on a good +12V source then move the black lead across the battery grounds and then the bus bar. Do the test wih the batt charger off and look for a voltage drop at one of the terminals. a resistance test across each ground wire may also help as will an IR thermometer after pulling a good load (again with batt charger off)
Some others on the forum may be able to offer better advice. Good luck.
