I've got 3 x 250W panels (freebies) that have the glass broken ( its toughened so currently still all together)
I presume they work , but haven't tested them yet.
I was thinknig of sticking some clear lament film over them to hold them together and waterproof them a bit
perhap a new sheet of glass bonded on top will be better.
Anyway, dont think I'll add them to my existing grid tide system but was thinking of sticking them on the shed roof and mucking about with them in some way , any ideas , seems a shame to bin them.

cheers Jim

In all probability the cells will be bonded to the glass with EVA film. This will help keep the glass together and the broken cells (if they have broken) will still work fine.

If you can get a sheet of low iron glass (for low loss) and seal it to the front face then you have a reasonably good chance of making the panels usable. They will give a lower output, but should work fine for charging batteries for a shed/garage/low voltage power supply. Definitely don't throw them out, as they would be ideal for something like an electric bike charging station.

The toughened broken glass will have lots of air channels between the pieces, which will detract from the performance by interfering with the light transmission. From my school days, I remember that something called 'Canada Balsam' has the same refractive index as glass, so applying it or a modern equivalent to the glass surface, filling the air gaps, should restore the transmission path and seal the surface, restoring the performance to near design level.

Be sure to measure short-circuit current with a suitably-rated multimeter, in decent sunshine, in case any of the cells themselves have been cracked. If you see much less than the rating on the label (Isc or Imp) on the back it then the panels may not be worth the trouble.

Rgds

Damon

Posted By: WillInAberdeenMaybe "their resin" would stick your glass together again?

I probably was already

Posted By: Joiner............ If you've ever seen it done, the resin has to be contained until it's gone off or it runs all over the place. It's like superglue.

And UV cured, not exactly a DIY job at least not without the right equipment.

The cells themselves are pretty robust and immune to most chemicals, I've found (I've made a few DIY panels now, using bare wafers). The problem of blocking useful wavelengths is real, though, which is why I made mention of just putting another sheet of low iron glass over the top. Ordinary glazing glass, even uncoated stuff, has higher losses than the low iron stuff made specifically for panels.

Having said that, I have panels with acrylic, clear PVC and clear resin on the front and they all work acceptably well. I'd not recommend covering with resin unless it's something like Sylgard, though, which is specifically formulated to stay clear (and hence is expensive!). I know of people that have encapsulated cells in epoxy and even polyester resin, and it works OK at first, but the resin goes yellow with age and exposure to sunlight, reducing efficiency.

The way to make a near-perfect repair would be to just laminate another layer of low iron glass on the front with a bit of EVA film, but this needs a heated vacuum press to work acceptably well and isn't likely to be an easy DIY option. EVA film is the stuff the manufacturers use to bond the cells to the glass usually.

Very impressive handiwork ST, the theme may be a little telling but impressive nonetheless.

"pour 10,000 bottles of beer down the drain "
the horror !

As in
'The Beer has turned up'
 

"crystal clear" MS polymer , Evan , if its the Everbuild stuff it goes yellow over time just to warn you
great stuff for allround waterproof fix though.

One panels has a large dent where they tried to break it with a hammer , with no luck, they're currently lend up against my fence were i unloaded them of my van , so not much progress yet. I'll report back when I get round to testing them , probably go for the low iron sheet over the top fix or just stick them on ebay.

was toying with the idea of sticking them on the roof and having them on a seperate systems (from the fit sys. already up there)
then just feeding direct into my immersion with the 3 panels in parallel (120V and 8A at STC ) and not grid tied , any thoughts on that ?

how come someone was trying to stick a hammer through them?

No problem at all with feeding an immersion with DC, if the voltage varies then the power it chucks into the water will vary, that's all. You can just hook a string of panels up to an immersion heater directly, no need for blocking diodes or anything else, and they will chuck whatever they can into the heating element. For best results, try and find a low power heating element, one with a maximum power rating that's only a little bit higher than the maximum that the panels will put out.

Think I'm going to stick them on ebay due to lack of free time ( and probably have a play with solar thermal for DHW ) anyone here interested in them for tinkering around with.
click on my user name for contact details
1 x hyundia 250W
2 x philidelfia 250W
damaged glass, but tested and working

Damon , thanks for your kind offer
I've listed them here http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=330732266109
cheers