# Repair cracked/damaged solar panel



## mightybooboo

I got this 50 watt panel for free,but it has a problem.The glass is cracked,but it still puts out spec rated power.

How to fix? Only thing I can find online is put a new piece of glass over it and silicon glue it to frame.Hmmmm....glass.Cheap but dangerous for breakage.
Tempered glass?Too expensive
How about Plexiglas?Expensive and it can yellow.
Lexan?Good stuff,VERY expensive.

So I looked into resins.
Fiberglas,kinda pricey,can yellow.
Polyvinyl?Same thing.
Epoxy resin?Very good,very expensive and very difficult to use.

Ok,now what? Why not polyurethane? Just paint it on.Cheap.Water based.Can layer it pretty thick.Yellowing? I will cover it in UV protecting car POLISH,not wax,when done.Several coats of polish.

OK,thats the plan.

Here is the panel.Totally shattered.Dead for sure with first rain.

Click to enlarge.Dialup warning,huge 2.5 MB pictures!

Lots of cracks



Clean the glass.Now let dry completely,I did 4 hours in sun,we do not want to trap moisture...




Im using satin finish clear water based polyurethane,18 dollars a qt,had some laying around here...




Stir gently,do NOT shake,dont want air bubbles...




Painting it on pretty thick.Dont be alarmed by color white or uneven.We will use full length long axis brush strokes to even it out...


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## mightybooboo

First coat on,notice how even it is and it will also even out even more as it sits....




First coat dried pretty good to touch in an hour in 80 degree shade.2nd coat on.This coat found some more missed spots,a few little holes filled in too...




Now the 3rd coat.Remember,smooth it out with long uninterrupted long axis brush strokes...




3rd coat on,its looking good.Notice it is a bit opaque,it will dry clear.3 coats,an hour between each coat...




More to follow tomorrow,Im thinking maybe 6 coats.


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## mightybooboo

This is AM day 2.Panel we are working on is on the left.

The panel looks pretty clear but coating is a little soft,it will bake in sun today,a good thing...




4th coat applied...




Question was asked,why so many coats if voids filled? Im trying to recreate some rigidity to panel that was lost when cracked.Cells just lie on a very thin metal backing,its the glass doing almost all the supporting of the cell field.

OK,maybe overkill with the pics but I want to document changes with everything I do...

4 is dry...




Coat 5 is on....




Question was asked,why so many coats if voids filled? Im trying to recreate some rigidity to panel that was lost when cracked.Cells just lie on a very thin metal backing,its the glass doing almost all the supporting on the cell field.

I may need to add some support to panel.


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## mightybooboo

The results,pretty good clarity....




Before repair 3 panels together put out 16.8 volts no load. Same after repair

Panel is rated 20.1 volts open circuit,puts out 16.8v at 70 Celsius.
That is right about where it should be.

A Panel rated 19.8 volts open circuit,puts out 17.1v at 70 Celsius, 
A Siemens monocrystalline in same array.

So numbers look pretty good.

Has a couple problems yet.The cell field is mushy,needs a couple backside supports.Or maybe some hard foam between cells and plywood bottom cover,and it needs to be mounted on plywood to provide torsional stability.

As for the glass crack repair? Looks like a success.I will let it bake for a week and put on several coats of UV polish to protect urethane.

BooBoo <----"It'll NEVER Work!"


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## Seeria

Very interesting. Let us know how it holds up, please.


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## mightybooboo

Seeria said:


> Very interesting. Let us know how it holds up, please.


For sure will update as it ages.My nephew has exact same problem and is going to try urethane too.

.................


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## wy_white_wolf

A better fix might be to use a couple of the kits that are made to attach mirror mounts to windshildes.


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## mightybooboo

wy_white_wolf said:


> A better fix might be to use a couple of the kits that are made to attach mirror mounts to windshildes.


Dont grasp concept,any linky would be most helpful,Thanks!


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## wy_white_wolf

A little humor

http://www.swapmeetdave.com/Humor/Workshop/Mirror.htm

The proper glue:

http://www.autogeek.net/revimiad.html

It would take several kits but should be a lasting repair you wouldn't have to worry much about.


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## mightybooboo

wy_white_wolf said:


> A little humor
> 
> http://www.swapmeetdave.com/Humor/Workshop/Mirror.htm
> 
> The proper glue:
> 
> http://www.autogeek.net/revimiad.html
> 
> It would take several kits but should be a lasting repair you wouldn't have to worry much about.


Yes,probably would work but pricey indeed I would think.I liked the epoxy resin idea best but so expensive and difficult to work with but what a nice cover that would make.


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## wy_white_wolf

I just posted the first link I found. I pick them up at my local place for under $2 each. Now if each one would glue 6" of crack how many would have been needed to fix your panel. I know that urethane runs $10 to $12 a quart (just looked yours was $18) and you will need to buy something that is UV resistant and build a stiffer backing. I think they might compete with your fix on a cost basis. 

Maybe one should also look at a time and labor. How long did you spend coating them? How much time is going to be needed applying and reapplying a UV protectant? What's going to happen if you forget to apply it as needed? I think using the windshield mirror glue would be a onetime deal and your done with it. I know I always prefer less maintenance.


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## mightybooboo

I probably spent 4 hours on it,Polish once a year,I will put on 4-6 coats I think tomorrow,shouldnt take much maintenance to keep polished up.That will last a year easy.

I would put UV protector on any fix I made I think,wouldnt trust UV to not yellow anything we could apply.

Used about 40% of qt. of urethane.

Just my thoughts,Im open to anybody elses fixes too.

Thanks for the good questions about time spent and such.

WWW,did you look at the cracks? Its shattered,not cracked,would pretty much need to coat entire surface,doing just cracks wouldnt be an answer (If thats is what your are thinking),miss just one and that panel is toast first rain.


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## SolarGary

Hi boo,
Just a thought, but I wonder a thin sheet of polycarbonate film "glued" down on the cracked glass would work? I think that sign shops carry thin polycarbonate film. Not sure what one could use to glue it?
One advantage would be that the polycarbonate might stiffen up the panel a bit, which I think you said was mushy?
It would have to be UV treated polycarbonate.

Gary


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## mightybooboo

SolarGary said:


> Hi boo,
> Just a thought, but I wonder a thin sheet of polycarbonate film "glued" down on the cracked glass would work? I think that sign shops carry thin polycarbonate film. Not sure what one could use to glue it?
> One advantage would be that the polycarbonate might stiffen up the panel a bit, which I think you said was mushy?
> It would have to be UV treated polycarbonate.
> 
> Gary


Good one Gary! Lexan (polycarbonate film) film,I like it!

24x48 inch is about 20 bucks.All you would need is a 'glue' of some sort.Looked at Lexan panels with silicon sealer around frame and set on Lexan panel would be a very good fix.It was a good option,but very expensive.

Lexan film would be a worthy candidate price/protection wise.I would try it.

As for mushy,yes the loss of the glass is a problem and the film really wouldnt help that much.Maybe would secure up the mushy cell field *a bit* but the panel frame just has no torsional bending strength resistance.You can even bend em a bit with the glass covering,doubt film would do much in that regard.

My guess from what Ive seen is either front or back of frame needs a solid reinforcement of some manner.


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## mightybooboo

Also keep costs in mind.This is a 50 watt panel.You dont want to spend too much on a repair that may not work longer term,you get into diminishing returns cost wise real quick on such a small panel.

So that was a large consideration in doing this.

My goal was to find something that worked,was cheap,easy,and had a chance at success.I still dont know what this will do long term.I may or may not have a winner,but what the heck,I tried.SO FAR Im major league impressed with how this panel looks and performs,its very good. SO FAR.

And hopefully it will work longer term too and I will have added to the knowledge base on panel repair,their isnt much at all on the web on this subject at all.

Need other folks to step up with some ideas and repairs too so we can fix these things,until we try some ideas we have very little,we can do this I have no doubt.

Lets get the info out there.


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## mightybooboo

This is the UV blocking polish Im using...
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Finish First Polish
FINISH FIRST uses a synthetic emulsifier cleaning agent to dissolve tar, road film, dirt and organic contaminants which cling to the paint even after washing. With this dissolving cleaning action, you will not create those "swirl marks" in your paint finish usually caused by organic wax cleaners. Not only will FINISH FIRST not create swirl marks, the cleaning emulsifiers will dissolve the contaminants embedded in old swirl marks and make them disappear. FINISH FIRST is unique to organic waxes because of its synthetic formula.

FINISH FIRST actually works better if you let it dry on your vehicle before removal for a minimum of 15 minutes to 2 hours. FINISH FIRST POLISH/FINISH is durable, weather resistant and able to build layers in order to enrich the depth of gloss. A regular wax coating, which is not durable, lacks the ability to build layers because the solvent grit of the second coat destroys the first coat. With FINISH FIRST the more coats you apply, the deeper the gloss and the greater the protection.

19.99/quart
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Does it work? These are the plastic lamp covers on my 8 year old Jetta.Crystal clear as new,you wont see that on unprotected cars....




Here is 5th coat drying...You can use this in full sun,wipe on,dry 10 minutes or so and wipe off...




After 5th coat dried and wiped.Put on a last coat after this pic I will let bake all afternoon then wipe off...


-------------------------------
Total costs?

Urethane- about 8 dollars

Finish First - About a dollar

..............[prophead]


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## danoon

I hope it works, I have some experience with varnishes and I think I would have gone with a good exterior spar marine varnish. Interior varnishes don't hold up to sun and rain very well. 

With the number of coats you have on it, it just might work but I'd keep an eye out for cracking and flaking within a few months.


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## mightybooboo

Yep,going to be fascinating to see how it plays out.


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## greg273

Neat idea, sounds like its working out pretty well. Hope I never have to try it though!! I did mention it to a guy i met at a campground in Colorado last week... he was the 'official host' for the place, and he had 2 75watt panels that he would just move around during the day to track the sun. Geuss he had some time on his hands...well the wind caught one of them and shattered the glass. 
That tempered glass is pretty tough, on that same trip we visited my cousin, who had a pane of tempered glass ( 1/8" I believe) fall out of his under-construction greenhouse, hit a large rock and NOT break.


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## Windy in Kansas

Looks great for an relatively inexpensive fix. 

Home Depot now sells corrugated clear sheets. Not sure they would fit the panel though with out two to cover the width. My thoughts are that they are very thin polycarbonate which I doubt yellows over time like fiberglass does. Rather reasonable in my opinion for cost. After more information on them I think they would probably work well for a greenhouse.


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## Jim-mi

For a backer plate you could use much cheaper easy to cut acrylic . . . out of the sun . . .yellowing not an issue.


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