I have a Carver 33 SS 2006 with four batteries. Two engine starters, one house battery, and one generator battery. Connected to shore power, all batteries charge. Running the gennie also successfully charges all the batteries. While underway, the engines are not successfully charging the house battery though the voltmeters for both engines are showing charging at 13 or 14 volts.

I say that because after being underway for 6 or 7 hours the CO monitors beep indicating a low battery charge, and the chart plotter, etc. turns off. Running the gennie re-charges the house battery eventually. Also, as soon as the gennie is on the CO monitors stop beeping and the chart plotter and other instruments are up and running again.

I installed an AGM battery for the house a year ago, when the house battery that was installed failed. The other three battery are conventional wet cell batteries. Any idea about how to go about checking for charge to the house battery from the engines?