Initially we were hosing them off twice a day. This removed some of the ash, but we noticed it gradually building up. Soon it became obvious there was a problem. If I used a rag and I could reach a 3 foot wide area around the border of the solar panel set up, but couldn't reach further. A better solution was needed. Someone suggested a pressure washer. Good idea but we can't run one without buying a bigger water pump. Our water system uses a dc marine pump, too small to supply the necessary water volume for a pressure washer. So I was looking around for a different solution. I rag on a stick might not be a good idea, because if the stick poked through the rag it would damage the solar panels.
I thought of a car washing brush, the kind that runs water through it. Might do the job nicely and quickly. A good friend of ours lent me theirs. So far, so good. If it works well, I plan to order one. I already tried our two local hardware stores and auto store, but no luck. So I'll need to look further afield.
Setting things up was easy. Attach hose, turn in water. Watering the panels down and rinsing off what ash I could, I then sloshed on a couple buckets of soapy water, just for good measure. Now it's time for the hose/brush.
Quickly I learned that I needed a step stool. The brush with hose attached was heavy and awkward to use from the ground. I retrieved the stepstool from the kitchen. Too short. Replaced that with a step-ladder. Ok, I'm in business now I thought.
Using the hose/brush, I quickly learned a few things....
...It's heavy. The brush and pole are light but add water and the weight piles on.
...It's very awkward to use while balanced atop a ladder. It's a bear when reaching the center of the panel bank.....no leverage, really difficult to steer.
...Once the panels are wet it's impossible to see where I've brushed them already. The brush seemed to work, but it was very difficult to make sure it's got the entire panel effectively. The brush needs to be at the right angle or it doesn't remove the ash. General swishing about doesn't do work. Once the panels dried, I saw that I missed about 50% of the surface. 50% removal of ash isn't good enough, especially since some parts were fairly clean and other areas still heavily coated.
...The plastic pole isn't strong enough. This tool might be perfect for washing a car at ground level. But holding it higher above the ground appears to put more pressure on the plastic pole than it can deal with. The water on/off piece broke almost instantly, necessitating a trip to the hardware store to buy a replacement. The weight of the hose filled with water was too heavy.
So I'm back to looking for an easy yet efficient way to clean the solar panels each day that we have ashfall. I might be looking closer to that rag-on-a-stick idea. Perhaps I just need to modify it a bit.