Electrical Troubleshooting

[richp]

So this is a fifth wheel question, at a minimum directed at arveetek.

I have 600 watts of solar that have seamlessly worked through a Trimetric/Bogart controller and monitor for years. Several years, I lived for months at Quartzite with no need to use the generator. Camped with it just three weeks ago and it was working perfectly.

This past week, the battery state as shown on the monitor started dropping day by day and when it got to 70 percent I got concerned. Pulled the batteries (two Trojan T105s) and after sitting for 24 hours, they were at 6.4 volts -- full charge.

Operationally, the jacks and other 12 volt devices work fine. When I kill the master power, the few things that stay hot (jacks, breakaway switch) continue to work properly. But the monitor still shows a reduced battery state after a week when we had great sunshine -- even with batteries testing very good and virtually no other use.

This system has always stayed well ahead of the few small phantom loads I have. I suppose the controller and/or monitor could be on the fritz. But does anyone have ideas about what else could I do by way of troubleshooting?

[DmaxMaverick]

I had something similar with a solar powered driveway gate. The diodes on the charge/maintenance control board failed, allowing the panels to discharge the battery when solar activity fell below balance. I simply installed diodes inline from the panels, and the problem disappeared. Dirty, fogged (oxidized) or failing panels can act similar, failing to maintain sufficient power. Lastly, and most obvious, is a parasitic drain you may be unaware of. Turn off everything and check the circuit with an ammeter. Cover the panels and check the leads for a parasitic drain.

[arveetek]

The monitor should show correct battery voltage, regardless of solar panel input. Even with zero solar panel input, the monitor should display what is actually in the batteries.
Since you say the actual 12V system appears to be functioning fine, I would suspect either a faulty monitor, or a bad/corroded connection between the monitor and the batteries. Typically the monitor is a separate component from the charge controller. Measure the voltage at the controller. If the voltage is normal there, then check connections between the monitor and controller. If everything seems normal there, a faulty monitor is likely.

Casey

[arveetek]

I had something similar with a solar powered driveway gate. The diodes on the charge/maintenance control board failed, allowing the panels to discharge the battery when solar activity fell below balance. I simply installed diodes inline from the panels, and the problem disappeared. Dirty, fogged (oxidized) or failing panels can act similar, failing to maintain sufficient power. Lastly, and most obvious, is a parasitic drain you may be unaware of. Turn off everything and check the circuit with an ammeter. Cover the panels and check the leads for a parasitic drain.

From his description, though, it sounds like his batteries aren't actually draining, but that his monitor is simply showing an incorrect voltage.

Casey

[richp]

Actually I've inaccurately stated the situation, now that I have absorbed your responses and more precisely reconstructed the problem.

The monitor showed, and after battery testing and reinstallation still shows, 12.6 volts. So it is telling me I have a fully charged battery.

I somehow neglected to fully absorb that fact -- distracted as I was by the monitor saying the state of charge was declining significantly.

Since I've tested the batteries and verified they are good, that suggests the panels and charge controller were indeed putting juice in on these nice sunny days. The mystery -- which likely lies in the monitor's functioning -- is why it was showing a declining percent of charge in the battery when the resting voltage was 12.6 -- fully charged.

I may try calling Bogart Engineering tomorrow to see if they have any ideas.

Thanks for helping me focus my thinking...

[richp]

Just spent an hour on the phone troubleshooting this with the owner of Bogart Engineering, which makes my Trimetric controller and monitor. We confirmed several different ways that they are operating as designed.

Next possible culprit is the panel wiring on the roof. At 73 with a bad back and creaky knees, I hate getting up on that roof, but oh well...