Cleaning The Array

We noticed a few days ago that we didn’t seem to be getting as much power from our solar panel array as we used to, in spite of some really clear skies. So we took a closer look at our panels and decided they must be dirty.

It’s not even difficult

Cleaning the panels should be a regular maintenance activity, probably at least once a month, if not once a week. We really need to get better about preventive maintenance in general, actually, for both the trailer and the truck. Keeping on top of that stuff is very important for safety, longevity of the equipment, and performance. But right now we totally suck at it. The last time we cleaned the panels was when I swept snow off them in, uh, April. Since then, the wind and rain have been all that was keeping them clean, aside from a few times I peeled wet leaves off them (a hassle in the pacific northwest). I’m surprised we were able to get away with neglecting them for so long – I know for sure I saw bird poo on them at one point, but that is magically gone now…

Anyway. Cleaning the panels is easy, here’s how we did it:

Get up on the roof.
Rinse the panels with water and wipe it off with a rag. It takes about 1 quart for each of our 4 panels, so this job consumes 1 gallon of precious freshwater.
Admire the view (or try to get cell signal) for a few minutes while the sun dries the panels.
Clean with glass cleaner and a new clean rag.
Dry the rags in the sun and toss in your laundry to be cleaned and reused.

It’s a 15-minute job (unless your ladder is hard to get out), and all you need is some rags, glass cleaner, water bottle, and a ladder. If you’re not familiar with RVing, the ladder may seem like an inconvenient item to have along, but most of us have one already anyway for a variety of RV-related reasons. Someone once told me you can identify a fulltime RVer because they have a ladder tied onto their rig somewhere… We use a gorilla ladder, which is heavy but I love how versatile it is, and especially that it can be used as a free-standing stepladder. I bought it like 10 years ago expecting to be disappointed, and am still astonished at how useful the damn thing is.

Why?

In this photo, can you tell which 2 panels I had already cleaned and which 2 were still dirty? With the clean ones next to them to compare, it’s pretty easy, but when you’re just looking at them from the ground they all seem fine. It only takes a little bit of dirt to make a BIG difference in output. To illustrate this, I recorded our charge controller’s output while I cleaned the panels, and here’s what it looked like: