Milky Solar Panals

[CalicoJack]

We have four flexible solar panals mounted on the roof of our cockpit. When we were last at the boat, just before lock down all was well, but on our return recently, two of them have turned a milky white colour , which is effecting their output. I have tried to contact the people we brought them from but with no success. Does anybody have any idea as to how we can remove the milkyness and restore full out put?

 

[neil_s]

A good clean improved matters for me - but not 100%. I suspect the UV gets to the plastic eventually.

 

[Trundlebug]

I had exactly the same problem with our semi flexible panel.
It was only a few years old and the plastic surface went milky, as said above the uv seems to get to the plastic outer.
TBH I didn't try polishing it (i.e. compounding) as it was clear it was uv degradation and I didn't think much could be done.
So earlier this year I swapped to a rigid panel as the only way to overcome the problem.
Advantages:-
1. Much higher efficiency (310w vs quoted 150w, which it never got close to putting out even from new in perfect conditions). Output of the new panel is fantastic so far, very pleased.
2. Better value - about £125 for the rigid vs £300 for the semi flexible
3. Longer life - glass topped, designed for house roofs and 25 year life with minimal degradation

Disadvantages:-
1. Heavier - 16kg (although this is light for a rigid panel, many are around 18-19kg) vs about 5kg for the semi. I don't like weight high up on a boat. And it's sitting on the sunroof, making opening & closing more difficult
2. One size has to fit!

So if you can possibly change to a rigid panel, do it. But if you can't:-
Try compounding the surface with a polisher and some coarse compound.
If that works, protect the surface with some quality wax or even better, one of the many Ceramic coatings now available from the detailing world.

Hope this helps

 

[thinwater]

Be VERY careful with compounding. This has caused microcracking and ruined panels. VERY low pressure. Most likely the damamge is through and this won't help. Better, waxing a lot seems to help.

 

[paulajayne]

Try a test area with Brasso and a soft cloth.

 

[NormanS]

My panels are rigid, so don't have this problem, but it seems a bit pathetic for PV panels not to be able to stand up to sunlight.

 

[duncan99210]

I’m normally only too happy with stuff I buy off eBay but the one time I bought some semi flexible panels off there, they did exactly the same as the OP. Since then, I’ve bought from either Marlec or Photonics Universe, as their products whilst more expensive do actually last. I’ve got a pair of 40 watt panels that‘ve been in position for 6 years now, yet to show any signs of problems in the surface, unlike the cheapo ones which lasted all of a couple of season.

 

[JumbleDuck]

I’m normally only too happy with stuff I buy off eBay but the one time I bought some semi flexible panels off there, they did exactly the same as the OP. Since then, I’ve bought from either Marlec or Photonics Universe, as their products whilst more expensive do actually last. I’ve got a pair of 40 watt panels that‘ve been in position for 6 years now, yet to show any signs of problems in the surface, unlike the cheapo ones which lasted all of a couple of season.

I have a very nice Photonic Universe 50W semi-flexible panel on my boat. It survived four years very nicely, but by last summer (year 5) it had gone milky all over.I have a replacement tough panel from Sunpower waiting to go on. Looks the business, cost four times as much ...

 

[thinwater]

Previously I had rigid panels (my PDQ) and the glass help up fine for 10 years until I sold the boat. Small wonder.

Added a 50W semi-flex panel that was cheap (I forget - about $100) on that boat for 1.5 years, and then transferred it to my F-24 for about 2.5 years. About 4 years total.

It fogged up after about 3 years. I wish I had waxed it diligently, but I hate waxing. Since then I have waxed it a few times and it helps a little. It certainly sheds dirt better.

That said, the output has not fallen very much, perhaps 1/3. Assuming some of the deterioration is in the cells, the inference is that the fogging does not actually reduce transmission that much. I wouldn't expect it to. It's not like they turn white, only foggy. Since I really only use the panel to maintain the battery and recharge after the rare night aboard, I really don't care much.

I would not risk compounding semi-flex panels, since there is risk of fatal damage and little chance of significant improvment, since the fogging runs the depth of the plastic, not just on the surface. Just clean them, a little wax, and enjoy them as long as they last... which won't be 20 years. Make them easy to replace and don't sweat it.

 

[ltcom]

I have recently bought a small 20w semi flex. would simple varnish protect it? like we use over epoxy? All my other panels are rigid glass.

 

[Bobc]

The cheap PVC ones do that. It's just the thin pvc film on the top that goes milky.

When you eventually replace them, go for ETFE panels instead. They are tougher and last longer.

 

[Jmc1764]

I replaced old white panel with a ETFE black panel, these are thicker and have a kind of textured surface, they seem very well made and this one is 55w and on a sunny day it is showing 3-4 amps on the charger. It keeps both the engine battery and the aux batteries fully charged all the time,