Originally published 10/24/2012
Oh, one more opportunity struck when I went to bed last night. The fuse inside the connector that runs the CPAP directly off of 12 volts blew. Requires a Phillips screwdriver to get access, and those are buried in a toolbox in the truck bed. The fuse? Amp rating unknown, and the manual is kept inside a buried bin. Spare fuses – if I have one this size – are in a storage box in an external-door storage bay. I hooked up my old spare inverter and ran it on AC power. Electrically speaking, this was just not my day.
About 2 AM, I awoke to the sound of some kind of fur-bearing varmint, probably a rabbit, playing with the rear wire cabling that runs from a solar panel to an exterior socket. That’s not good. Varmints tend to like to chew through wire insulation, and that’s never helpful. I put some clothes on and went outside. I’d already gotten the front wiring harness off the ground, but the back harness was not reposition-able until I could re-hang the panel feeding it onto a different set of mounts. Not something that can be done in total darkness – it’s difficult enough in daylight. So, back to bed – until a half-hour later when the rear wires again tapped against the camper. I made some noise, got 
dressed for the day, went out again for fun, warmed up a little coffee, and took some battery readings.
The house batteries, despite having no load on them that I’m aware of, had dropped from 12.45V to 12.24V. Sounds tiny, but it’s pretty notable. That means that the battery’s state of charge went from 75% to 50%. It means either that there’s some significant parasitic power draw from some device that I’m not aware of, or that one of the two house batteries is failing and is dragging down the healthy one’s voltage from trying to keep it charged. One is new, and the old one had just passed a load test at the RV place. Could have been its last hurrah, because the violence of a load test can finish off a marginal battery. No way to know without methodically pulling out one, putting it on a conventional battery charger until done, letting it sit unprovoked overnight, and then measuring its voltage. Then do the same to the other battery. If one is below spec, replace it. If they both test healthy, then something naughty is pulling power. This kind of check out does take time though, and is best done with a conventional 120V charger on shore power. I’d have to pack up and cross the street to the other gift shop to do that. We’ll see how today goes first.
Fascinating as this was, I fell asleep on the couch. By 6:30 AM, the sun was thinking about coming up, and both controllers were on active charge already. Steady green light = power charge. This is very good news. The panels weren’t producing much more voltage than the batteries had, mind you, but it was enough to kick each controller into gear. The next question is: will the controllers stay on active charge as the panels put out much more juice later? Oh, the suspense!
The answer hours later: yes and no. The single CPAP battery charged normally, more or less, and its charger went into maintenance mode only after a decent battery voltage was reached. The dual house batteries kicked into maintenance way prematurely, and their voltage quickly fell back into problem territory. A call to a different BatteryMinder tech indicated that doing the individual long term battery tests was advised, and that I should disconnect the old battery to see if solar function comes back to normal on the new one, just like the CPAP did. Meanwhile, conventionally charge and test the old battery. If those results don’t shine, it might take a couple of weeks to desulphate before coming back on board, if ever. Time-wise and expense-wise, that doesn’t fit what I can do very well, so I’m going to assume that the new battery is good, conventionally charge it, and try the solar controller with it solo tomorrow morning. Meanwhile, I’ll replace the suspect battery with whatever similar deep cycle battery I can find around here.
With one system up and running, that bodes well for getting number two rolling. I’ve got a fighting chance.
Reminder: there’s no cell data signal at all even in Winslow – this is sent courtesy of a McDonalds restaurant. Don’t expect another post for many days, okay?
Strolling Amok 