Solar power considerations for deep winter

We’re three days past the solstice and it has barely mattered, with heavy overcast and lots of rain. Overnight the sky cleared…

…and now everything outdoors is frozen solid. But it’s nice to see the sky again.

What with what I’m still hoping is only a new learning curve concerning Ian’s batteries, I’ve been considering moving his solar panels. Due to ongoing construction, back in 2009 we built his panel rack facing pretty much due east…

…which gives it great winter sun first thing in the morning but puts it in shadow halfway through the afternoon. We planned to move it at the time but never got around to it because it works where it is and since I couldn’t move it alone anyway I’ll never get around to doing it right. But it did get me thinking about panel placement.

I have two panel mounts, facing in somewhat different directions, and I have found that that accidentally worked to my advantage.

The first rack faces magnetic south, because that’s the way I built the cabin having forgotten all about declination. In summer it really doesn’t matter because this is the SW desert and we get lots of sun but in winter the mistake is an advantage…

Because the ground mount, which faces true south like the manuals tell you to do it, is in shadow until almost 8:30.

When people started using solar power more commonly, solar panels cost so much that a very great deal was written about proper panel placement to get the last possible erg of charge out of every one. People even bought expensive (and unreliable) tracking racks to make (or imagine they were making) their panels track the sun across the sky. You were supposed to change the angle of your panels seasonally. There were elaborate charts you filled out to calculate your demand to ensure you had just enough panels to barely do the job. It was daunting. Shortly before I moved here the Chinese got into the market, the price crashed, and now you just pile on panels until your batteries are charged by mid-day and don’t sweat it.

So hail Mao, I guess. Even so it is something to keep in mind because shadows are definitely not your friends and it’s a good idea to look and see every now and then if a tree has grown between your panels and the sun, or if what seemed like great placement in June maybe isn’t working great for you in late December when you need all the help you can get.