I have been off grid for a while. Mostly. Things are great when the sun shines, but it doesn’t shine every day. The next 9 days are forecasting rain, in fact.
Last night I came out to the cave and discovered the batteries were down to nearly 50%. Uh oh. If you want lead acid batteries to have a long, productive life you don’t go below 50%. It seems that SHE-Who-Pays-No-Attention-To-My-Edicts ran the clothes dryer on cloudy days, twice in a row. Hoo boy.
So, I flipped the switches back to the grid. Not everything goes back to the grid. The three a/c units are hard wired to the solar system, so on THIS rainy day, the batteries were not exactly overflowing with kilowatts. I like to exercise the generator once a month, so as I write this, the Kubota is buzzing merrily outside.
The Sunny Island inverters, which try to run everything, also like to equalize the batteries every month and that takes hours of generator time, which translates to a lot of Diesel. Have you priced Diesel lately? I have about 600 gallons at last year’s price, but still…I equalize quarterly and do a RUN 1 HOUR command monthly.
In the meantime, there are two ways to avoid flipping the switch back to the grid: Use less or make more. Have you noticed that human nature does not want to let you give up anything you’ve had? That leaves the choice of make more.
The aforementioned SHE has suggested that I make the Man Cave larger. A gift from heaven or, as a friend has suggested, perhaps she just wants me out of the house without the expense of a divorce. Either way, that would give me more roof space for more solar shingles. Granted, that would be more north-facing roof, but that does not seem to matter a lot in the summer when I need it. Lumber prices are dropping, too, so I am drawing up my bill of materials.
In the meantime, what about a tuneup to get at all I’ve got? The west bank is easy to keep clean, as is the lean-to bank. Moving the lean-to bank to a somewhat easterly ground mount would perk things up, but the big oak is not completely down yet. The Solar Shed shingles seem to have come with a permagrunge. I will invest in a new long window washer/ motorhome scrubber and see how that works out. Clean panels are productive panels.
But there’s more. In taking down the Zero Export Grid Tie experiment, that left 2 kw of panels off line. It took a couple of tries to get them running and they are a big help. I need to update and nail to the wall a system diagram to better keep up with where each of around 400 panels is connected.
Then there was simply resetting the charge controllers. I don’t know if they got addled by a nearby lightning strike transient, but a couple picked up some watts after turning them off and back on. One of them was hundreds of watts better.
Finally, my setup allows me to easily isolate individual strings for evaluation. I discovered that two are stone dead and one is, shall we say, relaxed. That’s nearly 3 kw out of service and that would be handy when the sun comes out between showers. There could be some corroded MC3 connectors, but the most likely issue is blown diodes on a couple of panels in the dead strings. I built the arrays with extra, unused shingles, so after finding the offenders, it is quick to insert a jumper cable and get things running again. On the wimpy string, I am betting on good diodes and a couple of dead panels. Getting that extra 3 kw back will be great. Maybe I won’t have to throw that switch back to the grid next month.
My RUN 1 HOUR is up. Time to go check if the Sunny Island is going to try to hijack the genset. In the meantime, try to consider if a tuneup might help your system.
–Neal