Speaking of which what's the general view on keeping the panels clean. Mine are covered in a thin layer of sand/dust/whatever the crap was floating around over the last couple of weeks. I was going to hose them down/brush them off but we're in a hard water area and I'm sure I spotted somewhere it's not recommended as you run the risk of building up limescale so better to just wait for rain.
Solar panel production figures
- Thread starter Ron-ski
- Start date
Not all, its been woeful here yet again today. Its the 5th day in 7 here with no sun at all! (And 8 days where it hasn't got above 15C, so the panels are cool at least).
It was "bright" though so we generated 15.1kWh and exported 7.7kWh, but looking at the forecast it's at least another 4 days of this until the wind off the North Sea bringing endless cloud finally changes.
Soldato
- Joined
- 7 Sep 2020
- Posts
- 3,693
- Location
- Gods Country
Woke up to rain…..that was defo not in the forecast. Flaming bbc
I was told not to wash them with tap water - also a hard water area.
The weather down here in Cornwall has been amazing. Last day we used over 1kW of electricity was 9th May, so approaching nearly a month of being pretty much off grid. Usually had our 17.5kW batteries full by 12-1pm every day, which only get down to 30-40% by the time the sun rises the following morning. 
Love it!
Love it!
Soldato
- Joined
- 21 Jul 2005
- Posts
- 20,739
- Location
- Officially least sunny location -Ronskistats
I watched a few videos and seen some doing it. General info seemed to be using a soft like pool brush but best time to do it is when you give them time to dry without sun rapidly intervening (so evening time for my East panels and early AM for my West panels). We live in the country and dont have the town water hardness issues thankfully. The dust/pollen/grit was quite noticeable.
I've got good access to my panels, so do regularly clean them and can see close up what effects that has on them. I use a water fed brush and car wash liquid. Panels definately needed a wash this weekend.
I'm not sure where this limescale rumour comes from - do you have limescale build up from washing your car? If I were to just spray them (no scrubbing), didn't get all the soap off and the water drys very quickly on a hot panel, it would leave streaks - which I'm guessing is what they're meaning by limescale build up. It's no different to trying to wash a black car in the sun tbh.
Secret is, plenty of water - and washing them outside of peak times (altough enough water will cool them anyway). The dust they get is quite clingy - and does take a bit of agitation to get it to shift. I've also noticed that I get some green build up at the lower lip that takes a bit of a scrub to remove. My panels are at a relatively shallow angle, so perhaps more prone than others.
I've also tried using rainX on the panels - which did work pretty well repelling dust build up. Cleaning afterwards was a lot easier - came off with just a spray. However that seems to have worn off now.
Last edited:
Soldato
- Joined
- 7 Sep 2020
- Posts
- 3,693
- Location
- Gods Country
I did my panels in the evening at around 8pm, there was no direct sun on them then, but being two storeys up on the roof it wasnt easy. They dried nicely with no streaks etc etc, but we live in a soft water area and welsh water add extra softener to the water too.....so limescale issues or build up of calcium
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,003
- Location
- Wilds of suffolk
I've got good access to my panels, so do regularly clean them and can see close up what effects that has on them. I use a water fed brush and car wash liquid. Panels definately needed a wash this weekend.
I'm not sure where this limescale rumour comes from - do you have limescale build up from washing your car? If I were to just spray them (no scrubbing), didn't get all the soap off and the water drys very quickly on a hot panel, it would leave streaks - which I'm guessing is what they're meaning by limescale build up. It's no different to trying to wash a black car in the sun tbh.
Secret is, plenty of water - and washing them outside of peak times (altough enough water will cool them anyway). The dust they get is quite clingy - and does take a bit of agitation to get it to shift. I've also noticed that I get some green build up at the lower lip that takes a bit of a scrub to remove. My panels are at a relatively shallow angle, so perhaps more prone than others.
I've also tried using rainX on the panels - which did work pretty well repelling dust build up. Cleaning afterwards was a lot easier - came off with just a spray. However that seems to have worn off now.
If you have hard water and you do not 100% remove it then if you let it evaporate it will 100% leave behind residue. Its not a rumour, its simple reality.
Ask anyone who lives in a hardwater area, shower screens, taps, sinks, toilets etc etc. Where ever you have hard water then you will leave deposits behind, but its much worse where the water is allowed to evaporate since 100% of the hardness will be left behind.
You can get limescale build up on paint on cars! Its why some go dull, however the surface is typically waxed and as such as the wax erodes then the limescale is also removed since the surface it is clinging on to is now gone.
There is also a balance of repetition. Possibly if you just did your panels once every 6 months then the effect over the lifetime of the panels may be unmeasurably negligible, but if you do it frequently enough to make a difference then its likely to form a noticeable film if you don't 100% get it off.
I think I need to convert one of my larger drones to carry a spray bar and then hook it up to a pump and some deionised water… the panels are too difficult to reach to clean, and they are covered in plant jizz.
Can’t be helping my production!
Can’t be helping my production!
Man of Honour
- Joined
- 5 Jun 2003
- Posts
- 91,549
- Location
- Falling...
If you use captured rain water that works perfectly for cleaning panels as it's often devoid of minerals.
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,003
- Location
- Wilds of suffolk
Yes 100%, if your going to want to regularly clean your panels then captured and settled rainwater is the best (or RO if you have a handy source like I do from work
)Both RO and rainwater can be very slightly acidic which is handy to clean stuff off.
Many people however want to go from ground and just spray them which really needs mains pressure.
I have a water tank pump and it wouldnt be powerful enough to get a decent quantity of water up to roof height.
I do wonder if you could get a long enough pole brush that you could do from ground level.
Man of Honour
- Joined
- 5 Jun 2003
- Posts
- 91,549
- Location
- Falling...
Yes 100%, if your going to want to regularly clean your panels then captured and settled rainwater is the best (or RO if you have a handy source like I do from work
Both RO and rainwater can be very slightly acidic which is handy to clean stuff off.
Many people however want to go from ground and just spray them which really needs mains pressure.
I have a water tank pump and it wouldnt be powerful enough to get a decent quantity of water up to roof height.
I do wonder if you could get a long enough pole brush that you could do from ground level.
You can use those window cleaning poles which brushes on them - but I'd be worried the brushes may scratch the panels - not sure how tough the coating on the panels are.
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,003
- Location
- Wilds of suffolk
Are they long enough? I hadnt looked at them. I guess a brush that could reach to 4th floor would be long enough to get to the higher panels on my roof.
I had assumed the top layer was simply glass itself and that there would be no additional coating on top of that glass. They look shiny to me so I don't think there is any antireflective on there
Worth looking into I guess.
I've not got seen any scratches appearing on mine from brush bristles. It is glass, so should be pretty hard wearing.
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,003
- Location
- Wilds of suffolk
Just dug this up, so some do have coatings.
Pretty much covers the main conversations we are having here in regards coating, how to clean them etc
Must admit I am now tempted. But it will be from ground level so need to have a look at sensible priced options.
The lower half of mine (portrait mode) are more dirty than the top, we had some rain but not enough to fully clean them off.
Saying that there is rain forecast for about a weeks time. I have quite a steep angle so pretty convinced that once rain comes they will clean off fairly easily.
Going to try to check the manufacturer site to see of they use coatings. I don't think so, Canadian solar.
Pretty much covers the main conversations we are having here in regards coating, how to clean them etc
Must admit I am now tempted. But it will be from ground level so need to have a look at sensible priced options.
The lower half of mine (portrait mode) are more dirty than the top, we had some rain but not enough to fully clean them off.
Saying that there is rain forecast for about a weeks time. I have quite a steep angle so pretty convinced that once rain comes they will clean off fairly easily.
Going to try to check the manufacturer site to see of they use coatings. I don't think so, Canadian solar.
Last edited:
Man of Honour
- Joined
- 5 Jun 2003
- Posts
- 91,549
- Location
- Falling...
Depends how many stories your house has - I have a flat roof to the side of the "main" roof so can easily get a ladder and the window cleaning pole to reach - I'm just not sure if the brush is too harsh or not.
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,003
- Location
- Wilds of suffolk
This is also interesting as you can see the meter in real time.
Obviously its a properly nasty couple of panels hes cleaning.
But if you watch it thevast majority of the impact comes when he gets the bird poop off, the half panels being "dusty dirty" make only minimal difference to the impact.
Which would make sense as the panels are probably isolating a section due to the bird poop.
Obviously its a properly nasty couple of panels hes cleaning.
But if you watch it thevast majority of the impact comes when he gets the bird poop off, the half panels being "dusty dirty" make only minimal difference to the impact.
Which would make sense as the panels are probably isolating a section due to the bird poop.
Soldato
- Joined
- 7 Sep 2020
- Posts
- 3,693
- Location
- Gods Country
yeh i was able to get the dusty pollen off mine, but the bird poop i still there. No way i can reach mine with a brush, it was hard enough to get the right angle with a hose. To reach and get the angle with a brush, i would need to be out on the road.
We now have rain forecast for next monday, so lets see what happens if it arrives and washes the poop off lol
Last edited:
Soldato
- Joined
- 4 Aug 2007
- Posts
- 22,003
- Location
- Wilds of suffolk
Its two storey but the panels are portrait in two rows. Plus a gap at bottom so I am guessing around 7 meters from ground to top of panels with some realistic angle I would probably want at least an 8 meter poled brush.
Which seems perfectly achievable.
The issue then is getting enough water up there to make a real difference. Dipping an 8 meter long pole in a bucket would be pretty annoying!
I may drag my pump out later (its a water butt pump) and see how high I can actually get a stream of water to go.
Had a bizarre thought. My office and our spare room are at either end of the house. I wonder if I hold my hand out of the window with the spray gun attached to my butt pump in a bucket of water in those rooms if I can get enough angle to spray the panels.
Could get the other half to stand in the garden and direct!
Just hope I don't fire over the top as the neighbours are walking past lol
I could potentially use softened water then from the bathroom tap.