…I left the Battery Minder on my battery bank, stealing power from M’s Dome through my comically kludged-together string of extension cords. Yesterday I finally gathered all the cords back up. Mission accomplished.
First I just wanted to see how the system behaved with the batteries fully-charged, since my single 170-watt solar panel seemed incapable of bringing them all the way up from the woeful state they were in upon installation. Having accomplished that, it seemed prudent to leave the Battery Minder connected for several days and let it desulfate the batteries.
That actually went quite well. Yesterday we didn’t get full sun by any means (we’re still in the trailing edge of Monsoon here) and the charge controller started signalling a full charge in the early afternoon. And that’s with just the one panel. I wuz happy.
Naturally I decided to punish the system for its good behavior. I’ve got a bunch of scrap lumber I’ve been meaning to cut up and put on the firewood stacks, and yesterday I did that chore with my brand-new circular saw which the newly-rebuilt system will actually run. In less than an hour the charge dropped from 14.2 to 12.4ish. This was in mid-afternoon, so we weren’t getting direct sun anymore but it was still well back in the mid-13 range by around five. It wouldn’t do that before, which tells me the batteries are in better shape now.
Next weekend or the one after that I’ll get my second panel. I anticipate a more comfortable winter than last, electricity-wise. Last winter I burned a lot of morning kerosene. Another fine product of Redneck Engineering, LLC!
UPDATE: Okay: We settled in for the night with the batteries not at all fully charged. Used the lights and various appliances for three hours. I’ve just spent about three hours playing on the ‘pooter with no sun at all. Before the improvements this would have come under the rubric “torturing the system to death.” I just went outside to check my state of charge, and it’s still in the 12-volt range. The very low 12-volt range, but still. Battery capacity at both the top and bottom of the chart is much improved. Me happy.
Congratulations! It sounds like the Battery Minder is really helping. A second panel will certainly be a big improvement.
If you want to try another hillbilly engineering feat, try using your inverter to run the battery minder! The idea isn’t to charge the batteries (conservation of energy and all that) but to let the battery minder use its high-frequency pulsing-fu to continue the desulphating process. I think that can take a long time.
Try it at night first to see how much power it draws. Not much, methinks. You want to make sure it doesn’t mess with the charge controller, but I bet it won’t, so when you’ve gained some confidence just leave it connected all day long.
If nothing else, it will be worth it for the looks you’ll get when you show someone how you condition your batteries.