Best way to avoid panels getting dirty when mounted horizontally

[cajocars]

I have mounted a couple of solar panels on my garage (almost) flat roof. When it rains there is a puddle of water forming around the lower part of the panels (the inclination is not enough to allow water to escape) and when water dries, it leaves behind some dirt.
How can I avoid this?

 

[littleharbor2]

Tilt them up to at least 15%

 

[cajocars]

Tilt them up to at least 15%

That's the only thing I cannot change

 

[littleharbor2]

Then you're going to have to clean them quite regularly. That water evaporating daily will form mineral deposits that will need hard scraping if allowed to form daily. been there, done that on my 5th wheel roof mounted panels.

 

[murmeister]

Could you place a horizontal support (2x6?) under the top spar? The support would attach to your metal roof and the spar would attach to that elevated support. That would give your panels a little tilt. Obviously, I don't know the whole situation. Just trying to think outside the box.

 

[Hedges]

Well, you could cut away the aluminum lip, or remove aluminum frame at lower end.
Just splitting the joint in the frame a fraction of an inch could work. Until it gets plugged with debris, like the drain hole in bed of my pickup truck.
Maybe remove frame, cut a notch to allow draining, put back on panel.

 

[SeaGal]

That's the only thing I cannot change

Almost every PV panel installation guide I've read has and entry like this...

LONGi/Whoever suggests that tilt angle of module installation be no less than 10°, so module surface dust can be washed away easily by rainfall and frequency of cleaning can be reduced. And it is easy for accumulated water to flow away physically and avoid water mark on the glass surface which may further affect module appearance and performance.

So, as @littleharbor2 said, you'll just need to clean them / wipe them down often. Maybe use a squeegee on a telescopic handle after it showers?

 

[Checkthisout]

When water dries, it leaves behind some dirt.
How can I avoid this?

Build a roof over them to keep the rain off.

 

[hwy17]

I would use a file to cut two little drain channels in the frame.

 

[SparkyJJO]

Why can't you build a tilted panel mount mount on your flat roof? You'd get better panel performance too if you closer matched the sun angle.

 

[SeaGal]

I wondered that too, but a random guess (IIRC that the OP is in the UK)... could be that he can't get planning permission, which would be required if panels extend more than 150mm above roofline.

 

[cajocars]

I wondered that too, but a random guess (IIRC that the OP is in the UK)... could be that he can't get planning permission, which would be required if panels extend more than 150mm above roofline.

Yes, exactly. It was easy to mount them parallel to the roof; I know I could get better performance by tilting them, but I prefer to keep them like this.

I have thought of cutting a channel in the frame but I don’t want to risk damaging them


I have seen these on Amazon, do they work?

 

[Checkthisout]

Yes, exactly. It was easy to mount them parallel to the roof; I know I could get better performance by tilting them, but I prefer to keep them like this.

I have thought of cutting a channel in the frame but I don’t want to risk damaging them


I have seen these on Amazon, do they work?

Those are a neat idea.

Was this whole thread foreplay just so you could shill those?

 

[cajocars]

Those are a neat idea.

Was this whole thread foreplay just so you could shill those?

No, I just found them while actually looking for panels with pre cut drains (which I had seen before)
They seem to work as a syphon, although I don’t understand how they can create a completely sealed channel

 

[hwy17]

No, I just found them while actually looking for panels with pre cut drains (which I had seen before)
They seem to work as a syphon, although I don’t understand how they can create a completely sealed channel

Surface tension / capillary action might be enough to draw the water over.

 

[Hedges]

Maybe, but works better with liquid helium.

Superfluidity - Wikipedia

en.wikipedia.org

 

[cajocars]

I’ve just bought them; I’ll report back

 

[clayswen]

I’ve just bought them; I’ll report back

Did you ever try those solar drains?

 

[ToddG]

Anyone try Rain-X?

 

[SeaGal]

Anyone try Rain-X?

We did... worked wonders when travelling across French Autoroutes and German Autobahns, especially over 80 mph... didn't use the wipers for the whole holiday