Last March or so I bought 8 new 6V AGM batteries for my inverter system. The guy who sold me the batteries also installed them with custom wiring for $1K total. When installing them, his voltmeter was malfunctioning - it was doubling the volt read out. So, it was displaying 24 volts when it should have been showing only 12. He didn’t realize his voltmeter was messed up, so he hooked up my system at 6 volts instead of 12. When we turned the shore power off to allow the system to start inverting, nothing worked and my shore panel immediately tripped. He figured we needed to let it charge a little, but when it started charging my carbon monoxide detector started going off in the bedroom where we were working. We turned the system back off and tinkered with it more over a 2 hour period. Every time we’d try to let the batteries charge, the detector would start going off. Finally, I put my ear down by the batteries and I could hear a sizzling noise. We immediately disconnected it all and decided to sleep on it. The next day, he discovered the voltmeter wasn’t working and then returned to the boat to set the system up properly. All last season, the inverter system functioned well, except I was disappointed at the system’s longevity. I realize the power demand determines the longevity of the system, but I typically only have the full sized fridge, a tube TV, and large stereo going during the day while we’re swimming. At night, I turn off nearly all the lights and only leave small desktop style fans running. Still, my system trips off with only 6 ~ 8 hours of usage.

I’m worried my batteries were damaged by this guy who installed them. How can I verify this? The batteries are covered by a 1 year warranty, so I need to figure this out soon. Of course I asked the guy who installed them and he insisted that he couldn’t have damaged the batteries and the issue lies in my power demand or the inverter’s Auto Cut Off settings. I have it programmed to shut off automatically at 10.3 volts. There’s only 1 setting below that and I believe I was told that setting would damage the batteries.

What’s your $0.02?