busted panel glazing

System

I have a Matrix PW 750 (80 watt) panel ( http://tinyurl.com/2cjnbn ) never used, that I got for free. It looks like it was run over by a forklift or something. It is bowed a fair bit, and the glazing shattered in little bits but in place.

I was thinking of making a cover for it with lumber and glass. That would be heavy and bulky, but I have a good suitable sunny spot on the ground where I could set it up.

Anything I'm overlooking before I go ahead with this project? Any better ideas?
I'll test the panel first to make sure it functions.

mike95490

Re: busted panel glazing

The trick is to get as much raw sunlight to the cells, without shadows from the broken bits of glass.
Then you have to keep it dry. It's hard to beat the factory glazing for that.

Have fun

Roderick

Re: busted panel glazing

I don't know - might be worth considering an aluminum picture frame? If it were me, I'd use glass instead of plastic as a cover, as I'd be worried about scratches and discoloration. If I didn't live an a hail area, I'd ignore breakability and get the thinnest, cheapest glass I could, assuming I had no access to that special low-iron glass that's made for solar panels. And I'd seal the whole thing up with silicone roofing caulk.

Did you already test the panel, does it work well?

System2

Re: busted panel glazing

I just dragged it out into the sun and put a voltmeter on it, and it appears to be working just fine.

Looking a bit closer, the frame looks like it comes right off with a few screws. Only one thin aluminum frame section is bent, and only slightly.
The panel itself is bowed. But it looks like I could probably just unscrew the frame, separate the glass from the panel, replace with a new glass the same size, and voila.

Yeah, plastic wouldn't last too long in the sun here. So for practical purposes, maybe I should just get some glass at the hardware store? I should probably get the same thickness so that the pieces fit back together well.

Actually, this project is beginning to look a lot easier than I expected. Though I still might make a movable wooden stand for it. That way, when I need the oomph for equalizing, I can align it with my other panels, and when I don't, I can aim it in a neglected direction to get more juice late in the PM.

BB.

Re: busted panel glazing

To check the panel, place a DVM set to amps (typically 10 amp scale) and short it across the two PV panel leads. You want to see approximately the Isc or Imp of the panel... Just reading the voltage does not tell you if the connections are still solidly intact.

You would probably be lucky to get 1/2 power of of the repaired panel and replacement glass. Compare that value (work and materials) to just getting a good used panel or seconds (per Solar Guppy):

You can also buy brand new Sun-170 modules for $2.74 watts ( Non-UL , seconds ) from www.sunelec.com so at a minimum use that price point for comparison to used panels.

-Bill

Roderick

Re: busted panel glazing

Bill's recommendation of testing the current is good.

But assuming that gives even half the rated power, I'd still go for it. Sounds like a lot of fun, fixing it up! It's not every day someone comes upon a free panel of this size.

System2

Re: busted panel glazing

Thanks Bill. I finally got a new DMM and measured the current while holding it directly facing the bright sun on a clear day, about 80 deg.F.

Right around 1 amp, whereas peak is listed as 4.6.
So I guess it's destined for the landfill (sniff).

crewzer

Re: busted panel glazing

Loohan,

What was the test configuration for the measurement?

Regards,
Jim / crewzer

Solar Guppy

Re: busted panel glazing

Sounds about right, I had a 165watt fractured glass with similar loss in output, same result ... landfill material

System2

Re: busted panel glazing

crewzer wrote: »

Loohan,

What was the test configuration for the measurement?

Regards,
Jim / crewzer

Sorry, Crewzer, I don't understand the question.

BTW, when I said "while holding it directly facing the bright sun on a clear day," I was referring to the panel, not the meter :-)

I didn't have it hooked up to anything other than the meter, if that's what you mean.

BB.

Re: busted panel glazing

With a DVM set to ~10 amp scale, and the leads shorted directly to the panel's two output wires (I presume).

-Bill

crewzer

Re: busted panel glazing

I didn't have it hooked up to anything other than the meter, if that's what you mean.

Loohan,

That’s exactly what I mean. With nothing connected to the PV module other than the meter, all that you can measure is the open-circuit voltage, or Voc. No load on the PV module means no current.


In order to measure current, you’ll need a load on the PV module. One test configuration might be this:

1) Optimize PV module alignment w/r/t Sun

2) Set meter for current measurement per instructions.

3) Connect PV module (–) to 12 V battery (-)

4) Connect meter (-) to battery (+)

5) Connect PV module (+) to meter (+)

6) Read value of current from module to battery

HTH,
Jim / crewzer

System2

Re: busted panel glazing

Thanks, guys. Yes, I had done as Bill described.

Just now I did as Crewzer recommended, and, alas, got 0.8A with a brand new 12V auto battery as load, and 1.32A without load.

But shouldn't it be higher under load?

crewzer

Re: busted panel glazing

...alas, got 0.8A with a brand new 12V auto battery as load...

Doesn't sound good... the module may indeed be toast.

Sorry about the bad news,
Jim / crewzer