How clean are your solar panels?

[007 RED]

My small scale system has now been up and running on the car port for nearly two months. 

 

Over the past few days I've noticed that there seems to be a considerable amount of dust within the house even though my better half does a thorough clean every morning, so late this afternoon I decided to have a look at the condition of my solar panels.  Ouch, they were filthy as can be seen from the photo below.

 

 

No doubt with this amount of muck on them their efficiency is being reduced.   So I decided to give them a wash with the hose and a gentle 'scrub' with long handle soft pad.  Once they appeared to be cleaner, I used a soft rubber squeegee to remove as much water residue as possible and then finally dried them off with a soft cloth pad.

 

 

Blow me down, about 15 minutes after I had finished cleaning the panels it started to rain, just a short shower which was not hard enough to have cleaned the dust off the panels if I hadn't cleaned them first.

 

So questions:  How often do you clean your panels and how do you clean them?

 

 

[Crossy]

Ours get a hose and a gentle scrub with the pool brush (it has a telescopic handle) once a month or so (the gardener does them if there's nothing else to do), but I'm not really convinced it makes a massive difference unless they are terribly filthy.

 

[MJCM]

We (read I) are glad that we have a long hose (because my better half is a gardener) near our (at the moment) 3 Solar Panels!  So whenever I go down to there (and I see they are dirty) I will hose them down.

 

Don't have the sophisticated equipment that @007 RED is using ???? but that will be on our Shopping List next time we will be going to the City

Edited December 26, 2021 by MJCM

[Crossy]

What I would NOT do is use a pressure washer, too much risk of water getting where it's not wanted. Use dish washing liquid or your snow cannon (followed by the regular hose) if you really want to but we've never bothered.

 

 

[MJCM]

Just now, Crossy said:

What I would NOT do is use a pressure washer, too much risk of water getting where it's not wanted. Use dish washing liquid if you really want to but we've never bothered.

 

 

Pressure washer DONT yes I agree.

 

The power of them could also damage them (just watch the Episode of Top Gear where Matt LeBlanc tested a Power Washer ????  but that was real high powered one)

 

 

[Crossy]

11 minutes ago, MJCM said:

... but that was real high powered one

 

Now I want one!

 

Even one of the "safe" domestic ones will take your skin off if you are not careful when cleaning your toenails

 

 

[007 RED]

15 hours ago, Crossy said:

Ours get a hose and a gentle scrub with the pool brush (it has a telescopic handle) once a month or so (the gardener does them if there's nothing else to do), but I'm not really convinced it makes a massive difference unless they are terribly filthy.

 

It is very difficult to measure the decrease in efficiency caused by dust and dirt which has accumulated on the panels because there could be other factors involved in the loss.  For example: my 4 panels have been churning out about 7 units per day until the beginning of last week when all of a sudden there was a sudden drop to 4 units per day, which seems to coincide with the increase in air pollution.  During this same period there has also been a lot of haze and cloud cover.  So difficult to measure which was causing the drop.

 

From what I have read, it is often quoted that the build up of dust on a panel can reduce it's efficiency by as much as  5%.  So in areas with dry climates and where dust is a problem regular cleaning is advisable. 

 

I agree 100% with you that a pressure washer is not a good idea as they can damage the panel's seals, and that can be very expensive.  I also note from the manufacturer's advice sheet for my panels that they advise not to use chemicals or domestic soaps to clean the panels.  They indicate that chemicals can also damage the panel's seals and that soaps tend to leave a film residue which attracts dust.  They advise just using water and a soft brush.

 

When I cleaned mine yesterday, it was just with the garden hose and a sponge and squeegee on an extendable pole.  Only took me about 15 minutes and worked just great.

[MJCM]

Our panels are ground mounted (approx 1,5m+ above it) when our pump is running and for example we walk past the panels you clearly can hear the pump work at a slower speed, as soon as the sun is full back on it the pump is back to full speed!

 

My guess that cleaning of the panels will help and ours especially as they seem a gathering place for birds to sh*t on ????

[007 RED]

16 hours ago, MJCM said:

We (read I) are glad that we have a long hose (because my better half is a gardener) near our (at the moment) 3 Solar Panels!  So whenever I go down to there (and I see they are dirty) I will hose them down.

 

Don't have the sophisticated equipment that @007 RED is using ???? but that will be on our Shopping List next time we will be going to the City

The equipment I used was not really that sophisticated, in fact it's somewhat 'Heath Robinson' actually.  Our garden hose plus a simple extendable pole (1.5M) with a soft sponge and squeegee fitted.  Purchased from HomePro at princely sum of THB 249   https://www.homepro.co.th/p/1010005 

 

[MJCM]

1 minute ago, 007 RED said:

The equipment I used was not really that sophisticated, in fact it's somewhat 'Heath Robinson' actually.  Our garden hose plus a simple extendable pole (1.5M) with a soft sponge and squeegee fitted.  Purchased from HomePro at princely sum of THB 249   https://www.homepro.co.th/p/1010005 

 

Thx for the tip. I was only using the hose!! And with the additional panels for our Solar House coming it's going to be task to clean them!

[007 RED]

On 12/26/2021 at 6:19 PM, Crossy said:

Ours get a hose and a gentle scrub with the pool brush (it has a telescopic handle) once a month or so (the gardener does them if there's nothing else to do), but I'm not really convinced it makes a massive difference unless they are terribly filthy.

 

With 32 panels, maybe this could be your next project ????

[oznomad]

I did a little trial. With panels about as dirty as yours, I checked the output.

Gave them a good wash. Output the same.

Moral of the story - dont stress about a bit of dirt.

Disclaimer - if you live where sea spray could accumulate and start corrosion it's a different story.

[JBChiangRai]

My 54 panels are on the roof, I can’t even see them, actually I’ve never seen them.

[Crossy]

One of our solar street lights has a very dirty panel, I have no idea why that light accumulates more crud than the others, but it does.

 

Given that the manufacturers are not likely to be over panelling these lights I will leave it alone until it decides not to stay on all night.

 

[MJCM]

On the days (very seldom) when I water the garden I also give all the Solar street light (read garden lights as they light up the garden) panels a rinse down and some have real muck on them (Light loving insect breading ground ???? )

[mrwebb8825]

Just a thought but, why not cover the panels with a glass case/cover? Then you could clean with anything you want and never touch the panels.

[Crossy]

Very subjective test.

 

We have three identical solar street lights, as noted above one of them has a very dirty panel (for reasons unknown) the other two are dusty but about the same as the car port.

 

These lights have a very basic charge level indicator, 4 red LEDs.

 

So after being on all night:-

Mr Dirty is showing 2 x red plus 1 red flashing (flashing means it's charging).

Both Miss Cleans are showing 3 x red plus 1 flashing.

 

Suggesting that Mr Dirty started with a lower charge, I'll see what they indicate tonight after a day of sunshine.

 

[Tropposurfer]

I used (and will use hopefully about every 4 years they tell me) an Aussie nano coating tech product called Nanoman our our system.

I've used it on Oz homes where we have some of the harshest sun in urban (polluted) areas and it works amazingly! Repels dirt, dust, salt buildup  at the nano-level, also super hydrophobic. 

We use a water powered very soft nylon rotating head brush with clean water from the filtered tank system and quality alkaline car wash (nice and foamy) every month to wash it down with.

They are never dirty that I can see prior to washing them.

Warning to anyone who does not use an alkaline soap to wash very dirty panels down - just like any coated surface (all panels come from the factory with at least an anti-reflective coating) if you only use water AND rub the panels but use no alkaline component you will scratch through the coating/s accelerating the etching that manmade pollution and organic dust/dirt brings when the coating deteriorates. 

Its no different to washing your car properly (which when done properly avoids micro-scratching to the 2 part epoxy clearcoat). 

 

Always a good rinse first with a hose to loosen and remove as much of the dirt prior to the next step (I use a decent tap pressure with the nozzle set on a narrowish spray setting to blast the excess dirt off without being a too powerful jet, then soapy/foamy water (plenty of it), then a rinse down and a post-carwash wiping cloth e.g. chamois. This way you slow down the removal of the coatings at all steps of clean. 

I have taken a gander at the panels every time I wash them (the maintenance guys know not to touch the panels) and is no dirt, dust adhering at all, even in the dry season.

 

I cleaned the panels with high quality glass cleaner, then applied the Nanoman immediately upon install - before corrosion / etching could begin.

I also used a ceramic coating (hand applied with a wiping over action - as you do with cars) on all the metal parts -frames etc. 

All the cabling was/is wiped thoroughly with a silicon based coating every few months to retard the impact of UV and other rays.

4 hours ago, mrwebb8825 said:

Just a thought but, why not cover the panels with a glass case/cover? Then you could clean with anything you want and never touch the panels.

standard glass panels have a refractive index, and are not coated with anti-reflective coating (as all solar panels are) so you'll reduce the rays contacting the panels.

[MJCM]

^ Re: Charging Level

 

That charging level IMHO doesn't mean much. I think I have the same ones as Crossy and one only shows a max charge of 60% only MAX (no flashing led after a couple of hours.)  But it still makes it till the morning with ease.

 

 

[MJCM]

Re: Cleaning

 

We now have 6 panels in operation, and I have to clean them almost every single day. Why?

 

Because feathered friends (NOT my friends any more ???? ) like to sit on the edges and then use it as a Toilet ????

 

Fortunately the panels are "ground mounted" and thus cleaning is easy, just using lots of water and then a Chamois Leather Cloth to wipe them down.

[carlyai]

On 12/26/2021 at 6:37 PM, Crossy said:

 

Now I want one!

 

Even one of the "safe" domestic ones will take your skin off if you are not careful when cleaning your toenails

 

 

That would get rid of your prostrate blockages.

I remember a first job working at the Newcastle (Aus) Steel Mill and the trick with the compressed air feed was to stick it up someones clacker and pull the trigger. Caused a few industrial accidents as the force of the air ...well you can guess the results.

[JAS21]

54 minutes ago, MJCM said:

Re: Cleaning

 

We now have 6 panels in operation, and I have to clean them almost every single day. Why?

 

Because feathered friends (NOT my friends any more ???? ) like to sit on the edges and then use it as a Toilet ????

 

Fortunately the panels are "ground mounted" and thus cleaning is easy, just using lots of water and then a Chamois Leather Cloth to wipe them down.

Good idea to dry off as will help reduce deposits from the water. Maybe not the best idea to use a Chamois though. Microifiber towel would be somewhat better.

[MJCM]

42 minutes ago, JAS21 said:

Good idea to dry off as will help reduce deposits from the water. Maybe not the best idea to use a Chamois though. Microifiber towel would be somewhat better.

From the link I posted

 

Quote

Genuine chamois leather has almost no abrasive properties, and can be used as a very absorbent drying material for any automobile surface. This has made it a popular product for car cleaning and drying

I had mine send over from Europe, so not the ones you can buy cheap at a store here.

 

edit: i have used micro fiber cloth before, but the problem is that they don’t absorb water that good, so that is why the change to Chamois.

Edited October 25, 2022 by MJCM

[007 RED]

 

As you will have seen from my original post over a year ago, it would appear that I live in a fairly polluted area which results in my 4 x 450W half cut mono solar panels mounted on my carport roof continually suffering from dust/dirt problems.

 

Several members have suggested that this is not really a problem as the efficiency loss caused by dust accumulating on the panels is minimal, and that one should not become paranoid about cleaning them.

 

However, according to a recent study by the Massachusetts Institute of Technology, accumulation of dust and dirt on solar panels is a significant issue and can reduce the output of the photovoltaic panels by as much as 30% in just one month, so regular cleaning is essential.

 

https://news.mit.edu/2022/solar-panels-dust-magnets-0311#:~:text=But the accumulation of dust,is essential for such installations

 

OK, so about every other month I’ve climbed up onto the carport roof just after dawn, hosed the panels down to loosen the dirt/dust and this is followed with a gentle soft ‘scrub’.  I then give the panels a squeegee and final dry-off with a microfiber cloth to minimize any water residue.

 

I have to say it has been difficult (well impossible) to quantify what the output improvements might have been achieved after cleaning the panels, mainly because sun conditions change throughout the day and from day to day.

 

The one serious concern that I have is walking on the cement panel roof of the carport.  If one panel was to crack it would mean a fall of about 4 meters onto the concrete drive below, and at 76 YoA that could be a very expensive trip to the hospital, or possibly a cheaper trip to the local temple.

 

In an attempt to make the cleaning process possibly safer I am considering constructing a walkway next to the lower edge of the carport roof which would facilitate easier cleaning from a safer position.  To complement this, I decided late last year to investigate the possibility of obtaining a ‘professional’ solar panel cleaning brush and after some investigation/searching on the internet, I decided on a single head electric power brush with a telescopic handle that will reach the panels from the potential walkway.  Several companies offer such equipment and I opted to use Neexgent Energy Co. on Alibaba.

 

 

The normal price of the kit is in the region of 14K THB, plus shipping and customs costs.  However, after some negotiations with the company rep, I managed to secure a great deal for a kit for just 10K THB, including shipping and customs cost.  I placed an order, and the kit was delivered to my door in about 10 days. No customs charge.

 

The kit comprises: -  a 35cm nylon brush assembly; a 24V DC motor; a control/connection box (incorporating a small DC water pump); an AC/DC converter plus adapters; a 2.1 to 7.5 meter telescopic handle; water hoses and connectors.

 

 

Assembly was self-intuitive and extremely simple.  On turning on the control box switches the motor spins the brush assembly (about 300RPM) and water is fed to the brush at a flow of about 18 L/M.

 

 

 

My first attempt at cleaning the panels was from a tall ‘A’ type ladder placed by the lower edge of the carport roof.  Using the telescopic handle fully extended (7.5 meters) I was able to access all surfaces of the 4 panels.  However, control of the brush head was quite difficult because of the centrifugal force generated by the brush rotating at 300 RPM and I have to say that I felt a little uncomfortable not being fully in control.

 

 

My second attempt was made using my original method, namely getting onto the carport roof.  This meant that I only needed to extent the telescopic handle for 2.5 meters, and this gave me complete control over the brush head.  The panels certainly looked very clean when I finished.

 

 

Although the new ‘toy’ certainly makes cleaning the panels much easier, they still need to be dried off afterwards.  I just wonder if something like a wet/dry vacuum cleaner (Mr Henry) would work?

 

It may just be circumstantial but comparing the output of the system the day before against the day after cleaning, there appears to be a slight increase in power produced by the system, but as I said this may just be circumstantial.

 

So next priority is to get a walkway constructed.

Edited February 27, 2023 by 007 RED

[BritManToo]

1 hour ago, 007 RED said:

However, according to a recent study by the Massachusetts Institute of Technology, accumulation of dust and dirt on solar panels is a significant issue and can reduce the output of the photovoltaic panels by as much as 30% in just one month, so regular cleaning is essential.

That's BS, my panels are very dirty now and I doubt I'm losing 5%.

Batteries are still full by 2pm, I'll clean them when they don't fill my batteries up in the day.

[KhunLA]

Ours are clean, as it rained last week.   They'll get cleaned again mid May, or sooner, if it rains ... ????

[Crossy]

@007 RED do you have a link to your brush supplier please?

 

Our walkway is made from 25mm Shera plank 

https://www.shera.com/products/floor/floor-plank/uncolored-colored-GCW325303000221

I would arrange some brackets so it is horizontal rather than at the same slope as the roof, we definitely don't want you falling off.

 

I'm not convinced by the "30%" although there's no doubt that dust does make some difference. As noted, it's very difficult to quantify unless you're in a lab, the sunshine just isn't constant enough.

 

 

[007 RED]

15 hours ago, BritManToo said:

That's BS, my panels are very dirty now and I doubt I'm losing 5%.

Batteries are still full by 2pm, I'll clean them when they don't fill my batteries up in the day.

I have to say that was also initially sceptical about their 30% claim.  That said, a google search on loss of solar panel efficiency due to dust/dirt will throw up similar figures from a variety of sources. Personally, I wouldn’t just dismiss the article as BS, as you put it.

 

Bear in mind that MIT is one of the top universities in the world (#5 according to the Times Higher Education ranking) and I doubt that they would allow BS to be published under their name at risk of losing their reputation.

 

Given the opportunity, I think that it would be far better to ask:-

1.... How/where did they conduct their test(s)?

2.... How did they maintain a constant light source during the test(s)?

3.... What density of dust/dirt was allowed to accumulate on the panel(s)?

4.... How did you measure the loss in panel output efficiency?

 

As I mentioned in my post above, it is very difficult, if not impossible to determine with any accuracy what improvement cleaning the panels had made on the panel’s output as the sun strength and atmospheric conditions varies throughout the day. 

 

All that I can say is that comparing the maximum output recorded via the system’s monitoring facility, before & after cleaning, there was a slight increase from 1.19kW (for the 5 days prior to cleaning) to 1.25kW ( for the 3 days after cleaning), but this may well be subjective and due to better sunshine/atmospheric conditions.

[BritManToo]

1 minute ago, 007 RED said:

All that I can say is that comparing the maximum output recorded via the system’s monitoring facility, before & after cleaning, there was a slight increase from 1.19kW (for the 5 days prior to cleaning) to 1.25kW ( for the 3 days after cleaning), but this may well be subjective and due to better sunshine/atmospheric conditions.

So loss less than 5%, same as my panels.

[007 RED]

6 hours ago, Crossy said:

@007 RED do you have a link to your brush supplier please?

 

Our walkway is made from 25mm Shera plank 

https://www.shera.com/products/floor/floor-plank/uncolored-colored-GCW325303000221

I would arrange some brackets so it is horizontal rather than at the same slope as the roof, we definitely don't want you falling off.

 

I'm not convinced by the "30%" although there's no doubt that dust does make some difference. As noted, it's very difficult to quantify unless you're in a lab, the sunshine just isn't constant enough.

 

 

No problem... The supplier I used was Foshan Neexgent Energy Co. Ltd.  Their Home page is-

https://fsgxn.en.alibaba.com/minisiteentrance.html?spm=a2700.details.0.0.74b02051OpCg14&from=detail&productId=1600647586473

 

From the menu bar pull down the PRODUCTS list and then hover over "Solar Panel" to display another pull down list.  At the bottom of that list you will see "Solar Panel Cleaning" if you click on that you will see their various brush products they have.  You will see from their home page that they produce a fairly extensive range of solar equipment, including batteries etc.

 

Many thanks for the the link to the Shera planking that is certainly something that I will need. 

 

FYI... I mentioned walkway, but in fact as I only have 4 panels I think it is more likely to be a platform that will allow me to access the panels without stepping on the concrete roof sheets.  And yes, I intend to make the platform horizontal.