Originally Posted by 540art
I own a 1978-9 Airstream Excella 24ft. mid kitchen motor home.I can't keep the on board batteries charged.they charge when I'm running but not when I'm on shore power.Is my inverter messed up?
Hi Art. Yes, your converter may not be working, however it is also possible that you have a draw somewhere. In this case, the charge rate from alternator being much higher than your on board charger, may be able to sustain the charge in batteries. However, when on shore power, your discharge rate could be higher than what the converter is able to replace. Second thing to address, is the testing of your batteries. You may have one bad battery pulling down the good one. Once you are satisfied that your batteries are good, go to next step. Find the charge wires leading from converter to batteries. Disconnect positive side and place an Ampmeter in line of the positive wire. Plug in your Shore power. Observe proper polarity on your Ampmeter, they will read both ways, and you may observe discharge while it is actually showing a charge. With batteries partially discharged, you should observe same Amperage as the rating of your converter, unless batteries are unable to take a charge. Good reading on the charger may indicate that you have a draw somewhere as well. To confirm it, disconnect the positive wire from the battery. Hook up Ampmeter in line of that positive cable [observe polarity]. With circuit breakers off and all appliances and the switches off, you should not observe any draw. Draw at this point will indicate shorted wire from battery to circuit breaker box. Next turn the circuit breakers on one at the time, while observing the Ampmeter. With all switches and appliances off, if you observe a draw with the breaker on, that particular circuit is shorted. If no draw is observed on any circuit breakers with all appliances and switches off, the problem may be in one or more of individual circuits. Further tests are done by turning on one circuit at the time while observing Ampmeter. Any unusually high draw may indicate a problem. It is also possible that one of your appliances may be at fault. If you need more specifics PM me. Good luck. "Boatdoc"