Are Engine and House Batteries Connected?
On a long trip home, after stopping to get gas, I turned the key to start, and the dashboard went dark. After a bit of panic in the 95 degree weather, I tried the "battery boost" switch, and feeling ...
Forum Discussion
Olddud wrote:
I was able to do some checks this morning on the battery boost relay. Before doing anything, the house battery read 12.7, and the engine read 13.2. This was after sitting in my driveway overnight without shore power.
Turned the key to accessory (just before start), pushed the boost switch several times just for grins, and heard the boost relay operating. Started the engine and measured voltage (no boost). The engine battery read 14.4, and the house read 13.7. So I assume the alternator is charging the house battery. Wonder why the voltages aren't the same?
There is enough resistance in the battery isolator and wiring to cause that much of a voltage drop. Both voltages may go down as the voltage regulator responds to the charge state of the engine battery.
