Plane Hits Solar Array

[Ric Murphy]

Ok it was an RC plane but it still hit the array and shattered the glass in one of my 8 panels. Actually the wingtip hit the adjacent panel first then cartwheeled and the prop just caught the edge of the other panel. One more inch and it would have missed. The glass being tempered (I assume) shattered into a million pieces but stayed in the frame. We've removed the panel from the array and now am contemplating what to do. First we're going to verify output to see if the panel is still functioning (I'm assuming it is) and at what level. Since the glass has remained in the frame I'm assuming it must be bonded somehow to the cells. Is this common? Would there be a way to remove the glass and whatever it is bonded with? Lastly if the panels output is stilll reasonable could a person simply apply another layer of glass over top the shattered one? Obviously it would have to be sealed somehow to keep moisture out. Anyone have any experience trying to salvage panels with broken glass?
Ric.
P.S. The plane survived with only a broken prop.....$5.00 fix....go figure!!

[Rob Beckers]

Sorry to hear about the mishap Ric! (and where are the pictures? it didn't happen without a picture!)

Yeah, the glass sticks to the rest. In fact, the panel likely still works reasonably well. Between the silicon cells and the glass is a sheet of EVA, half a mm or so. This is a resin, comes in sheet form, and is heated to make it bond with both the cells and glass, immobilizing the whole thing. There should be another layer of EVA on the back side of the cells, and then the backing, usually made of tedlar.

So, if the EVA layer is intact it's actually still water-proof. My guess is though that it'll soon break along the fracture lines of the glass, and the wind will now move the cells back-and-forth much more than it did when the glass was intact.

On the bright side: The price of solar panels seems to be in free-fall!

-RoB-

[Ric Murphy]

Thanks for the info Rob. No pictures of the actual crash but here's one of the panel after we removed it. You are correct in that the panel is much less rigid now that the glass is shattered. So my idea of installing a new piece of glass over top may prevent moisture from getting to the cells (if sealed adequately) it won't solve the flexing issue unless it's bonded in at least a few places in the center of the pane. May or may not be durable enough to last very long. So the other option is to replace the panel. As luck would have it these panels are no available from the manufacturer. They are Isofoton 150S modules. 150w - 24V and wired in 2 panel series strings. Spces are:
Isc - 4.45A
Voc - 43.2V
Vmax - 34.6V
Imax - 4.35A
Any ideas on compatible panels? Which of the above specs must be the same or close to be considered compatible?
Ric

[Rob Beckers]

This is a 72-cell module, so any 72-cell module will match the voltage. If this is one panel in a single string (with no strings in parallel) you don't have to match voltage, making sure the current is at least as large as that of the other panels will do. If there are multiple strings in parallel then matching voltage is more important. By taking a panel that is somewhat higher Wattage and 72-cell you'll match both (the rest of the string will limit current to a value close to that of the other modules, the parallel string will limit voltage, so you don't get the benefit of the extra Watts, but it won't hold the rest back either).

-RoB-

[Rob Beckers]

To further the above: Electrically something like Canadian Solar's 160W CS5A-160P is a good match to replace the broken panel. That panel should be available at a decent price as well. The downside is that it's an entirely different form-factor.

-RoB-

[Ric Murphy]

Thanks Rob. The array consists of 8 panels, 2 in series x 4 strings in parallel. I think we're going to go ahead and add a new pc of tempered glass over the existing panel and reinstall. We'll take some readings on the repaired panel and the adjacent panel and compare output in identical conditions. If acceptable and the repair seems solid then we'll leave it up. If not then will look for a replacement. I'll look into pricing on the panel you suggested as well.
Thanks again for your input.
Ric

[Ralph Day]

Hi Ric
I wonder if anyone has thought about bonding new tempered glass over the shattered panel glass with epoxy resin. \No worries about moisture getting past a seal, however I'm not sure about the resin darkening over time.. If I had a busted panel I think i'd try epoxy resin first.

Good luck

[Joe Blake]

Due to an accident, entirely my own fault, and something I'm too ashamed to discuss, I shattered the glass on one my "fold up" PV arrays. I had a piece of clear polycarbonate sheeting spare, so I cut to size and taped it around the edges with good old duct tape. That was about 4 months ago, and the panel has been out in the weather (had a few torrential downpours) and it still works okay. At times there seems to be a bit of condensation inside the Polycarb, but the angle the panel is mounted at seems to cause the water to run to the bottom without affecting anything.

I won't buy a replacement (yet).

Ciao,

Joe

[Ralph Day]

Joe,

Bike hits solar array?:huh:

Ralph

[Joe Blake]

Er ... no.

http://forums.klipsch.com/emoticons/emotion-16.gif


Joe :embarrassedt:

Well actually, Just between you and me, I found the edge of the panel was always sitting on the cable, trapping it on the ground, causing bending of the cable, so I decided to cut a groove in the aluminium frame to allow the cable to sit within the frame. In the process of setting up the angle grinder I became disorientated and ground into the front of the frame, where the glass was, and soon started grinding THAT. It crazed immediately.

Anyway, it doesn't seem any the worse for its adventure with the polycarb sheet on, it's still delivering its quota of power, so I guess it's just a case of writing it off to experience. And it makes a good party story.

[Ralph Day]

Oh Joe,

Sounds like a story that happened during a party:bigsmile:

With any of my r/e stuff I really plan ahead and think it out...much more than any other job that needs doing. I've been accused of operating on chipmunk mode...too fast for my own good (chipmunks in AUS? small stripped ground squirrel if not). The r/e stuff is too expensive to make oops-ies on.

Latest, my Mx60 fan started to act up so I took a muffin fan, tie wrapped it to the open front and hooked it to my relay-ed circuit on "vent fan" mode. Keeps things cool enough that the little integrated fan doesn't run. A little white paint on the blades and I can see the fan when it's running and avoid sticking my fingers in the way.