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How to clean solar panels?
- Thread starter Carbonfiber
- Start date
nwdiver
Well-Known Member
I've found that it's generally not worth my time to clean the panels. Any performance increase from cleaning is short lived and the loss of production tapers quickly. The panels can only get so dirty...
I pay someone to clean my panels every couple of years or so. The team that does it are solar people and use deionized water and I get an inspection as side effect. It feels like a wash (pun not originally intended but I'm going with it) money/value wise.
skepticcyclist
Member
I just rinse mine with a hose connect to my soft water line. During Santa Ana wind season in the fall I may sometimes to do it every week, especially if there are a lot of fires. During the rainy winter season, never. During our dry the summer, about once a month
Merrill
Merrill
I use a DI system, comes with a fiberglass extension pole and brush does a decent job. I usually do it a couple of times during the summer depending upon Fire’s in the area which drop lots of ash.
kindofblue
Member
We have our outside window cleaner clean them with his de-ionized water set up when he does the windows. It's not too much more than just the windows and skylights themselves.
We had our roof done last fall after the fires in the mountains. It removed some material, but the percentage improvement was not huge. Maybe 10 or so percent.
I get mine cleaned, in general, once a year, when I get my windows cleaned (same company does both for me). For me, its basically a wash (the amount I pay for cleaning doesnt quite balance out the value of the increased solar production), but its close enough to not bother me too much and I like seeing the slightly increased production.
It wasn’t that bad for me. Roof is easily accessible with a ladder and it’s a one level house. I just used a window cleaner chemical similar to windex. Took about 20mins. The solar panels were a bit dusty. I could see it from the ground level.
I’m just not sure what the proper cleaning chemical is to use for solar panels.
I’m just not sure what the proper cleaning chemical is to use for solar panels.
My window cleaning person just uses deionized water and a brush (no chemicals). My home is two stories, with a cement tile roof. I am not going up there, lol.
dhrivnak
Active Member
In TN we get enough rain that there is no need to clean them. After 7 years, when cleaning some skylights, I did a good job of cleaning my panels. When I then compared against another solar install I found out that after cleaning my system did slightly less. I am sure it is just random error, but bottom line no gain for the time spent.
I think what I'm going to do as a test is to clean 2 of my panels, then look at the numbers for the following day and compare the output of those 2 panels to the panels adjacent to them to see what the production difference is.
I don't have Tesla panels, just a Tesla Powerwall2. I've got panels with micro-inverters and can see the production of each panel on my Enphase system.
I don't have Tesla panels, just a Tesla Powerwall2. I've got panels with micro-inverters and can see the production of each panel on my Enphase system.
CrazyRabbit
Active Member
Merrill
Merrill
I use a DI system with a special fiberglass pole and brush that uses that sprays the water thur the brush, uses very little water and does a pretty good job. I only do this when the panels get really dirty but does not really add more productio.
skepticcyclist
Member
Depends on where you live. West coast rainy season is in the winter. Even those areas in the PAC NW that get over 100 inches of rain a year will go all summer, 4 or more months, with no rain at all. Those in the SW US will get thick dust accumulation after just a couple weeks during the summer, and may go without rain for over 6 months. Cleaning is very important.
Where you live you get measurable rain every month of the year and don't have to deal with nearly as much dust. Of course you don't need to wash your panels. You will be guaranteed to get at least one good rain event every few weeks to keep your panels clean. So please don't accuse those who live in more arid climates of having OCD because of something that may be necessary to prevent a lot of production loss.
I've tried that, LOL. I have a 16-panel Enphase system, with the panel-level monitoring. It's harder than it seems to draw any definitive conclusions, even though it looks like a straight A/B test. For one thing, there is always a bit of variability in adjacent panels, as you've probably already observed, and is apparent even in the screenshot - in mine, particularly the ones by the edges near a hip or eave get different amounts of wind or air circulation, as well as exposure to the heat coming off the roof. So I would say best to have A/B pairs fully in the interior of your array, that you've observed have as consistent readings as possible - my arrays are only two rows deep, so I had no interior panels that worked well.
The other challenging thing is there's about a 10-15 minute delay before the real-time readings get from the micro's to the Envoy to the cloud, so if comparing power readings, you have to have some patience. Energy readings smooth it out, but again on my panels, the accumulated other effects over the day, plus daily shade rolling over the array, tended to obfuscate the specific effects of cleaning. Moreso because cleaning probably had a 2-5% impact, fairly small and thus harder to isolate from all the other effects.
Finally, make sure you wait about 15-30 minutes after cleaning before doing any comparisons, as just the mere act of cleaning the panels with any water cools them down and boosts their efficiency temporarily...
Good luck, look forward to seeing your results!
I am pretty sure that @sorka did a test similar to that and posted results. If I remember, the end result was (to paraphrase) that it does matter, but they get dusty fast enough that this would need to be a weekly or bi weekly thing for it to really matter.
In other words, it pretty much mirrors what @nwdiver (who is also a solar installer) said in post 2.
Edit:
Found the thread I was thinking about, its here:
Effect of dust on production
1 months worth of dust equals 4% of lost production where I live.
teslamotorsclub.com
FurryOne
Member
I noticed a few days ago that mine were covered with pollen. I hosed them off, and it removed some of the pollen but not all of it. I've since ordered a 24' solar washing tool from EquipMaxx so I can do a better job. The water running off the panels the first time I hosed them looked like running mustard. I got a couple of hundred watts increase in output afterwards. (PS... the same tool through Amazon is $40 more!)
