A Wee Bit of Dust Buildup Since Last Cleaning End of April...

[silversaver]

I'm glad this solution works for you. Maybe you can get closer to your panels, so that approach is effective in your case.

My panels are stacked 4 rows x 11 columns altogether, starting near the top ridge line of my roof. If I stand at the bottom of the roof on a ladder (don't want to go on top of the roof if I can help it), the top row is at least 30 feet away from me. So spraying water via a nozzle on that top row from 30 ft away is akin to spraying water on my dirty car from 30 feet away trying to wash it. From afar it may look cleaner than when filthy with dirt, but if you come up close, it won't look so as clean. The only way to clean effectively is to brush to agitate the dirt into solution then do a proper rinse then dry by wiping off or squeegee or rinse using pure water and let the pure water dry by itself.

Regarding using softener water, my tap water is around 800 ppm in total dissolved solid (TDS) reading (very high in hard minerals like Calcium and Magnesium). I have a water softener, too, and the softened water indeed works better with soap and feels softer to bathing and washing clothes. But it's still very high in TDS even after softened (reading is the same at 800 ppm TDS). That's because the water softener simply exchanges the Calcium and Magnesium ions with the salt ions. So instead of having a high content of mineral ions, now the softened water just has a high content of salt ions. The salt ions still leave stain on my shower door glass when I let the water dry on its own. Because of that, in my case, using softener water would also leave stains on my solar panels. It wouldn't be mineral stains, but it'd be salt stains.

All you need is a nice solid long ladder that tie to rain gutter for my 2 stories home. Or stand on patio roof top (if that's an option.) I agree to your point, but remeber: mineral/hard water stains will stay and tough to clean, but salt stains can be easy remove as a simple rain or frequent washes.

I refuse to walk on my tile roof, period.

[Volusiano]

All you need is a nice solid long ladder that tie to rain gutter for my 2 stories home. Or stand on patio roof top (if that's an option.) I agree to your point, but remeber: mineral/hard water stains will stay and tough to clean, but salt stains can be easy remove as a simple rain or frequent washes.

I refuse to walk on my tile roof, period.

Yeah, at that height you definitely need to tie your ladder to something. I don't have rain gutters in my home, but luckily my house is single level so my ladder rests securely enough in between the tiles at low height.

I definitely agree with you that salt stains is easier to remove than mineral stains. If you don't have pure water, softened water is better than hard water for sure. I feed softened water into my RO/DI system to make pure water because the RO membrane can reject the dissolved salt solids more effectively than the dissolved mineral solids.

I don't know if a simple rain can remove the salt stains, though. Hard rain probably can. Frequent washes may remove the salt stains if the water pressure is strong enough. But you'd end up with another layer anyway afterward. But anything is better than mineral stains. Those stains are WICKED to remove.

[Rdjntx]

This has been an interesting read to say the least. I was told by my installer (2012) that the panels did not need to be cleaned, that the rain and wind would keep them clean. Now you guys have me thinking that maybe I need to get up on my roof and take a look. I monitor my production from afghanistan and have not noticed any drop off so I am guessing they are in pretty good shape.

[Ian S]

This has been an interesting read to say the least. I was told by my installer (2012) that the panels did not need to be cleaned, that the rain and wind would keep them clean. Now you guys have me thinking that maybe I need to get up on my roof and take a look. I monitor my production from afghanistan and have not noticed any drop off so I am guessing they are in pretty good shape.

I think a lot depends on your local conditions. Here in Phoenix we haven't had any appreciable rain for months. My panels were filthy but still produced around 95% compared to clean ones. My shallow 15 deg panel slope probably doesn't help either. I also think the dust was a bit grimy/sticky which is not surprising in this smoggy urban environment.

[Volusiano]

I think a lot depends on your local conditions. Here in Phoenix we haven't had any appreciable rain for months. My panels were filthy but still produced around 95% compared to clean ones. My shallow 15 deg panel slope probably doesn't help either. I also think the dust was a bit grimy/sticky which is not surprising in this smoggy urban environment.

I think you hit the nail on the head here about the grimy/sticky dust in smoggy urban environment. That and the matte-like surface of my solar glass is why it's so hard to get the dirt off my panels completely in my case.

Yeah, rain would take care of it I guess, if it ever rains in AZ, LOL. I waited and waited and waited and finally gave up waiting. Can't leave things in nature's hand in AZ. Not gonna happen...

Monsoon season is coming but it'll probably be a dusty bowl of soup mixture between blown up dust storm and short bursts of rain water. Just enough water to mix with the dirt to create mud then dump on your panels. But never long enough rain to thoroughly clean things out in the end. The panels will probably end up being more dirty after a monsoon rain storm than before.

[geniusenergy]

It is definitely worth a clean! No need to clean it obsessively though

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