cleaning panels

[turbo2ltr]

My panels are really dirty, and I can see I'm losing a few kwh a day. It hasn't rained here in a while. Should I just go up there with a hose and hose them off or is that a bad idea?

[shrink]

I also had solar at my previous house and the installers would clean the panels quarterly for the first 2 years. I'd have to look at the manual again for specifics, but they just recommended a Windex solution, glass cleaning squeegee or fabric, and one of those long telescopic poles if I do it myself.

That said, I wasn't all that comfortable on the roof of my 2-story house, so I would just hose them down.

We had that dust storm/haboob on Wednesday and I have since noticed about 2-3 kWh reduction in daily production. Part of that is heat, too, but if your panels are accessible, I would clean them.

I can look up the recommendations in my system manual if you want.

[mwalsh]

I get up there once a year, usually right after the 4th of July. I do it in the morning, while the panels are still cool, and I use my car washing soap in water. I went to Smart and Final where I bought a double headed squeegee - mitt on one head, squeegee in the other - and a 15" pole. I mitt them with soaply water and then follow with the rubber squeegee.

[Boomer23]

I do pretty much the same as mwalsh. It's probably prudent to wash them when they are as cool as possible to prevent breaking a pane. In PHX, I assume that means starting at 0500 (?). Just like washing a car, merely hosing them down does some good, but actually adding some friction helps more. I just cleaned mine about a week ago after two years of neglect, and I can see about a 5% improvement in daily energy generation on full sun days. FWIW, I skipped cleaning them last summer because I wasn't seeing any detectable power generation decline.

When I washed them two years ago, I think I used some kind of gentle detergent with a hose-end sprayer. This year I just used water and a very long handled soft terry brush that I got from Lowes, made by Ettore.

http://www.lowes.com/pd_379237-1316-650 ... facetInfo=" onclick="window.open(this.href);return false;

And

http://www.lowes.com/ProductDisplay?par ... &cId=PDIO1" onclick="window.open(this.href);return false;

[GeekEV]

I haven't yet gotten to the point where I need to clean mine, but the thought of doing all that on my 2 story roof is daunting. I bet some of that windex outdoor stuff you attach to your hose would be better than water alone, no? Clearly not as good as a proper washing though.

[SilverLeaf]

Hosing the panels IS NOT a good idea in the Phoenix Area. Our water is high in mineral content and will deposit a layer of minerals over the surface. This layer is very difficult to remove.

Here is a link to one site that discusses the issue:

http://www.ewindowwashing.com/2010/06/0 ... ar-panels/" onclick="window.open(this.href);return false;

There are various solutions prescribed by various solar sites. I can provide some of those sites, if you'd like.

[KK6PD]

Geeze, I have had my 7.5 kW system since 2006, and I go up once a month and wash the whole system down. I have a monitoring system, and in the 40 minutes it takes, I regain 600 to 1.1kW of power back. For me, it's mandatory, and I have a flat roof with 60 panels! It's all about the sun baby!
Talk about reviving a dead thread .....

[dsh]

I soak mine with a solution of Dawn Powerclean and water, wait 3-5 minutes and hose off.

[DaveEV]

For me, it's mandatory, and I have a flat roof with 60 panels! It's all about the sun baby!

The flat roof is what makes it mandatory. My panels are mounted on my almost flat roof (about 4*). If I had frameless panels I could get away without cleaning, but as it is now I get up there a couple times a year and just wipe them down with a California duster when I see that panel production per panel starts varying a decent amount. Takes about 15 minutes. Doesn't get all the dirt off, but gets the bulk of it.

The problem with almost flat panels is that the lip of the frame traps a heavy layer of dirt/dust at the bottom edge which will eventually noticeably affect power output. If I were to do it again I'd make sure the panels were tilted up 10-15*, or as mentioned, used frameless panels.

[mwalsh]

Have not washed my panels down since the drought hit. Am losing some production, but it's only a couple of kWh. Will resume normal cleaning if we ever get out of this, unless I move out of CA first.