This morning I disconnected the four batteries I put there in 2019 and dragged them out to the yard, replacing them with the six batteries I bought yesterday. There was some fiddling in between: I needed a larger tabletop but I’d already cut that, and I needed to move the battery charger on the wall but that didn’t take long. Then I wired the batteries up and when the charge controllers came on line – I had 19 volts. Not 12. Not 24. 19. I needed 12. The inverter just gave me an error code. I had no power to the cabin except for DC. Which was 19 volts. This was not going to work.
So I did what I always end up doing whenever I have to mess with new battery configurations: I picked up the phone and whined to Neighbor S. He was wrapped up in something else but shook free about 3 hours later and helped me sort it out. And now it works.
There’s still some fiddling to do. The new series/parallel circuit required exactly one more cable than I had – but by pure coincidence BB had just sent me a spare he had lying around, possibly smelling my impending embarrassment. So not everything fits just right and I need some cosmetic retrofitting. And the battery charger isn’t hooked up because the positive cable doesn’t reach. But those are minor tweaks. The Secret Lair now has 50% more battery capacity than it did before. Actually far more than 50% because my old batteries were dying fast. It was imperative that I get this done before the cold. Happily, so far November has been very mild.
Now: The next question:
Can I use my hillbilly refrigerator, which has been sitting out on the porch since September? Stay tuned. Maybe I no longer need to haul ice from Ian’s freezer.
Good luck to you. I was never able to use refrigeration on solar, though to be fair, I was in Florida. You have more solar power than I did, so you have that going for you. But fridges not purpose designed for off grid tend to use a lot more power than they need to. (Not enough insulation)
This one’s got low power requirements and is never in the sun so it might be all right. I do admit it’s an experiment. On the other hand I’m the only one here who doesn’t have a refrigerator – my power system started super small – and I’m getting a little tired of the icebox business.
RE: fridge insulation. If there’s a source for polyisocyanurate insulation (aka “R-Max” among other brand names), it’s R 6.5 per inch, so 2 inches added to the exterior would – probably – slightly more than double the insulation (just make sure none of what you add covers stuff that needs free air access, like the motor and compressor). The door seals will be a weak point, but some careful design and cutting could provide overlap coverage to minimize losses through the door seals.
If there’s an outfit in The Big City that makes 4X8 sheets of the stuff, I have no doubt there are scrap pieces there somewhere, and, maybe, given that fairly small pieces would serve to wrap a small fridge, you might be able to scrounge some.
But, as Deb pointed out, unless your fridge was designed for solar use it’ll suck more electrons than one that is designed for solar.
Enquiring so-called minds want to know: how did you manage to get 19 volts?
Robert, I wonder the same thing. Neighbor S has a lot more experience than I do and he couldn’t explain it either. Just a modern miracle, I guess.
Sounds like two series strings of three batteries. Nominally 6 volts each, they probably run about 6.3v in reality, giving 19v.
Converted to three series strings of two batteries for right at 12.6 volts.