busted panel glazing

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System
System Posts: 2,511 admin
in Advanced Solar Electric Technical Forum #1
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.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
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    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
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
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  • Roderick
    Roderick Solar Expert Posts: 253 ✭✭
    #3
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    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?
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  • System2
    System2 Posts: 6,290 admin
    #4
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    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.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #5
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    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
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Roderick
    Roderick Solar Expert Posts: 253 ✭✭
    #6
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    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.
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  • System2
    System2 Posts: 6,290 admin
    #7
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    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).
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #8
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    Re: busted panel glazing

    Loohan,

    What was the test configuration for the measurement?

    Regards,
    Jim / crewzer
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #9
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    Re: busted panel glazing

    Sounds about right, I had a 165watt fractured glass with similar loss in output, same result ... landfill material
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  • System2
    System2 Posts: 6,290 admin
    #10
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    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.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #11
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    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
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #12
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    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
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  • System2
    System2 Posts: 6,290 admin
    #13
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    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?
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #14
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    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
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