Phantom Drain: Solved!

Our problem: We had a constant 3amp or so current drain. We’d also turned the air conditioner on accidentally when we were running on batteries. Subsequently, we basically flatlined our batteries (below 10.5 volts) during the night.

The next several days we tried to bring the batteries back up, but, with the constant 3amp drain and the batteries being flatlined, it took a large amount of solar to bring them up. We tried to use the charger on our inverter, but that wouldn’t work until the batteries were charged up a little. We had to run our converter at night to keep our batteries topped off.

The solution: The solution was two-fold. The current drain came from our fifth-wheel breakaway switch. The activator plug had been loosened just enough so that it looked, to the casual glance, like it was in. It wasn't, however, so the electric trailer brakes were on all the time. We only discovered it was out when we hitched up to move the trailer down to a solar shop. Since the trailer brakes were on, the trailer refused to budge. Putting the activator plug in all the way turned off the brakes and fixed the current drain.

The solar shop tested the batteries and seemed to think they were OK, that no lasting damage had been done. We’re not sure about that diagnosis, so we’ll be keeping an eye on their capacity and charging/discharging ability. The other interesting thing they found was that the other solar installer (back in 2003) had wired the negative pole of the batteries to the battery side of the shunt AND ran a wire from one of the negative poles to chassis ground .The other side of the shunt also goes to chassis ground. Our Link 1000 wasn’t giving us accurate current figures.

Anyway, the SB2000 and the Link 1000 now are within 0.05 amps of each other. As I type this in, we're pulling in 18amps from our panels (3 Kyocera 120-watt, tilted towards the south) and our batteries are charging right up nicely. The volts are still a bit different, but the solar guy seemed to think that was normal. The readings are closer now, however. So we can now resume our usual solar lifestyle, where most of our power comes from the sun and all is right with the world.

Thanks to BB, crewzer, and niel for their suggestions, hints, and observations. I've certainly learned a bit.