Hmm, I've got a few random thoughts. (Temporary solution: If you are in the process of moving the boat and need the house bank charged you can use jumper cables
, or make a set of cables
to parallel the house batteries with the starting batteries so you are charging while underway. I wouldn't do it with a gas engine
though, sparks in the bilge
It sounds like you have two issues, the first is a drain on the system that kept the 110v charger working overtime, and is your voltage difference. The other is lack of connection between the alternator
and the house bank, if the grounds are not shared by both systems the house bank won't charge even if everything is hooked up otherwise. Its like trying to jump start a car with only the positive cable, open circuit.
Do you have a battery switch to start from the house bank, if not you will want a switch that will start from each bank. Ideally you charge only one battery at a time, as the weaker batteries in the bank drag the strong ones down... and the regulator
cuts off late when it sees the voltage weaker battery. Ideally the switch is such that you can flip from 1 to 2 without opening the circuit, if it opens its the same as turning off with it running, fried diodes! Start on the starting battery, turn to the house bank once running and the plates of the house bank will thank you.
Turn to off after you are done running the engine
and the starting battery will stay charged.
If you already have the switch, take it apart and make sure the contacts are clean! I've seen the knobs pop off and people put them back on wrong so they always charge on both, or one bank is still on when it reads off. If everything is unhooked, ohm out between the poles if the switch is in question.
Check the ohms of the ground cables. The voltage difference between ground at the end, and between the terminal of the battery would show its self if the cable its self is at fault. Clean everything and slather the connections with dielectric grease or other corrosion
I'd also turn everything off and check for discharge at the batteries. Pull one of the cables feeding the fuse box and put a test light between the battery and the cable... if it lights up you've got something discharging. If you've got a multimeter with a fuse you can check the amp draw and an internal resistor. With everything off there should be no draw, or if your meter is excellent less than a three hundred milli-amps. At that rate a single
starting battery will still start you up after a month and a half of discharging.
If there is no draw, hook up each of the chargers one at a time and see if they are using power, or if a combination of two causes something funny
to happen. I'm betting you'll find something dumb like a corroded bilge pump
connection thats trying to make a battery in the bilge
I hope this helps you...