How do you clean your panels?

[AmitBajpayee]

For the effective benefits of solar panels, it is extremely important to clean them on regular basis. Dust particles and other irrelevant things present on the solar panel highly reduce the efficiency of the solar panels. Hence it is an ideal practice to keep their maintenance on high priority.

While cleaning the solar panel surface the care should be taken as its surface is made up of photovoltaic glass and should be handled with care. Make sure you do not use harmful objects like brushes and pointed needles it may harm the solar panel.

You can make use of dedicated liquid and sponges to clean the solar panel surface.

[J.P.M.]

I know this is old but has someone hired a cleaning company for this?

There are always outfits who will take money from fools.

For the most part, the effects of cleaning will last about 4-6 weeks without rain, will cost more $$ than it will save by improved performance, and may cause damage to your roof.

Read through the thread for an education and then make your own choice.

[fraiserdon]

I know this is old but has someone hired a cleaning company for this? I'm thinking of cleaning it by myself but also thinking about hiring a cleaning company. Like, is it worth the money? I don't want to waste them on something that I can do by myself. I mean, I work hard for my money, I'm not going to waste them AT ALL, haha. Anyway, if you're doing this by yourself, what tips can you give for a beginner?
So, I hope that somebody will see this and will respond. I really appreciate any help you can provide.

Moderator note: Please don't put advertising links in posts

[J.P.M.]

I had quite a bit of bird poo on a corner of my array and when compared to a panel three columns over that had no bird poop, power was identical as was daily kwh output.

I've decided the rain can do the work for me, even in AZ where it hardly rains. It just doesn't matter enough to do anything for it.

Well, if you can't notice a difference in output and you trust your instrumentation and methods, where's the problem ?

[J.P.M.]

Note! Dont use a pressure washer. There are too many seals and electrical components. Just hose off and use a car washing brush. One of the long handled rotating head car-washing brushes is ideal. Use a little dish washing detergent if you wish but make sure you rinse thoroughly to avoid detergent degarding any seals. Lichen can grow along the bottom edge of panels and may need a little more mechanical action than a hose off. I suggest using a plastic (rather than metal) scraper.

One thing to note is that water will cool the panels resulting in a short term bump in production. When you look at the inverter is will seem like there has been a big jump in production after cleaning however this is the result of cool panels not cleaning. People who operate as solar panel cleaners often use this to demonstrate the effectiveness of cleaning however once the panels dry off and heat up again production returns to about pre-cleaning value.

+1 on not using a pressure washer. Dumb idea and not necessary.

I use a VERY SMALL quantity of mild dish detergent ~ 1X/yr. and rinse thoroughly. Otherwise it's 1 X/month rinse with H2O only. BTW: The hard water spots don't seem to impair performance in any way I've been able to measure over the last close to 5 yrs.

NEVER scrape panels with anything more abrasive than a soft cloth, or risk damaging the ARC. Same for harsh cleaners/chemicals.

On cooling of panels: For starters, NEVER apply water to a panel when the panel is warm enough to be generating much electricity. Do it early in the A.M. before the panels get much above ambient temp. If you can see a momentary rise in array voltage/output, that is an indication that the array was probably too warm to safely rinse it.

As for the length of, or being able to spot any temporary temperature rise after cooling by rinsing, it's mostly a function of the diff. between initial panel and water temp., how cool the water got the panel, ambient air temp., dew point, wind vector and irradiance and some other stuff, all of which results in a panel temp. change, probably an increase relative to the cold condition immediately after the water was turned off. Then, if the panel is undisturbed by more water cooling, the panel temp. will increase depending on it's thermal mass, the irradiance level, and less the rate electric production to the panel as expressed very approximately by something called the thermal time constant of the panel. For my array, which is pretty typical, after a morning rinse with about 3/4 gal. H2O/panel, my best guess is that the thermal time constant is ~ 6 - 9 min. or so in an average wind of ~ 2m/sec.

Long, boring story, but bottom line, it doesn't take a panel long to reheat as f(irradiance), but if it's rinsed before the sun is strong enough to cause a panel to heat up in the first place, any production change will be mostly unnoticeable and unimportant.

[ImInPhxAZ]

I had quite a bit of bird poo on a corner of my array and when compared to a panel three columns over that had no bird poop, power was identical as was daily kwh output.

I've decided the rain can do the work for me, even in AZ where it hardly rains. It just doesn't matter enough to do anything for it.

[JohnyWalter]

Note! Dont use a pressure washer. There are too many seals and electrical components. Just hose off and use a car washing brush. One of the long handled rotating head car-washing brushes is ideal. Use a little dish washing detergent if you wish but make sure you rinse thoroughly to avoid detergent degarding any seals. Lichen can grow along the bottom edge of panels and may need a little more mechanical action than a hose off. I suggest using a plastic (rather than metal) scraper.

One thing to note is that water will cool the panels resulting in a short term bump in production. When you look at the inverter is will seem like there has been a big jump in production after cleaning however this is the result of cool panels not cleaning. People who operate as solar panel cleaners often use this to demonstrate the effectiveness of cleaning however once the panels dry off and heat up again production returns to about pre-cleaning value.

[Mike90250]

backside of panels is not meant to be washed, be careful cleaning out nests with water back there.

[Kingram]

I picked up one of these Little big Shot Super nozzle to reach the panels on my two story home-https://www.youtube.com/watch?v=Rsp_mDLSeOY

[Friday]

Yesterday I went on my roof to clean under my solar panels. Someone quoted me $700 to remove several bird nests, bird poop under my solar panels. All by myself I cleaned everything out in less than 3 hours.

What I use is a Bionaire water blaster, or as I simply call it my "RV pressure washer". It is designed to clean RV's, so it has an extendable nozzle up to 6 feet, and it compresses the water like a pressure washer. This is important because I have a 2 story house. With a normal hose nozzle there is no water pressure and it doesnt do a good job. With this its like having a pressure washer, it does a great job. I would highly recommend buying something like this. I even used it to remove the bird nests.

For reference this is what I have, but any home improvement store will have something similiar for only $10-15:

https://www.lowes.com/pd/BONAIRE-Ultimate-Water-Blaster/3597668

There's just no comparision to rain water or a normal hose nozzle with this. You have to be careful the first time I used it it surprised me how powerful it was and I was fell over lol.

[J.P.M.]

For what it's worth most solar panel maintenance sheets say no water over 125psi and ok to use regular commercial glass cleaners (Windex, alcohol, etc).

You can always look up the manual for the particular modules in question but generally they are all the same. Absolutely no pressure washing.

I imagine a hose with a sprayer attachment that let's you add chemicals, some glass cleaner in it, an a microfiber cloth on a pole is about all one would ever need if desired to clean the panels.

I was up on my roof yesterday just 6 hours after rain and the panels looked dusty already.

Safe to say ill take JPMs advice and I'm not going to play the constant cleaning game.

With my array fouling @ ~ 1% performance degradation/week, I figure a 1X/month simple hosing at a rate of ~ 3/4 gal./panel if it doesn't rain will hold the average fouling penalty for my array to maybe a bit less than 3% or so. Common wisdom is that fouling rates are local condition and climate dependent as well as tilt angle dependent.

Horizontal arrays will need a lot more cleaning to keep from becoming silt pans.

[ImInPhxAZ]

For what it's worth most solar panel maintenance sheets say no water over 125psi and ok to use regular commercial glass cleaners (Windex, alcohol, etc).

You can always look up the manual for the particular modules in question but generally they are all the same. Absolutely no pressure washing.

I imagine a hose with a sprayer attachment that let's you add chemicals, some glass cleaner in it, an a microfiber cloth on a pole is about all one would ever need if desired to clean the panels.

I was up on my roof yesterday just 6 hours after rain and the panels looked dusty already.

Safe to say ill take JPMs advice and I'm not going to play the constant cleaning game.

[J.P.M.]

Must be estimated. I can't see shoveling it up and weighing it.

Old Marine head graffiti: Flush hard - it's a long way to the chow line.

[littleharbor]

Must be estimated. I can't see shoveling it up and weighing it.

[J.P.M.]

80 pounds?? How did you figure that out?

Maybe it's not guano. Apparently Dumbo lives in his neighborhood.