How to repair a 75 watt panel?

BilljustBill
BilljustBill Solar Expert Posts: 219 ✭✭✭
I bought 5 Siemens 75 watt panels made in 1997 and paid $50 each. In a full mid-March sun, four of them tested at 22 volts and 4.85 amps.

The fifth one had one end of the aluminum fame was bent about 3/8". The panel only measures 10.2 volts, but 4.52 amps. I can flex the back of this panel and the voltage will jump around and go as high as 22 volts. Once performing at 22v, one bump and the voltage goes all over the place....

Is there a way to hunt down the fault and repair it? The 5" mono- cells look good and I'd like to use it if I can get a solid repair.. Ideas?

Thanks,
Bill
Bill

Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: How to repair a 75 watt panel?
    Is there a way to hunt down the fault and repair it?


    Hello Siemens, I need to buy a 75W panel.


    About all you can do is try work a warranty replacement, if they won't go for it, you have to go over the front glass with a magnifier in the crunched area, and look for something out of order. Torn or wrinkled tab wire, dark spot (from localized heating) anything that looks "different", is likely "bad". About the only repair, is to touch up a cracked solder joint. to do that, you have to peel the tedlar backing off (in the one area only, not the whole panel). and resolder, or touch it up. Then use magic repair stuff to seal the panel water vapor tight, and it will last 20 more years.
    When you find the magic repair goop, let us know.

    If you are really lucky, it has bypass diodes somewhere and their solder joints, 1 is bad, and you can retouch that.

    Good Luck Mr Phelps.
    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 ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: How to repair a 75 watt panel?

    my guess is at least one cell was affected by an abnormal physical hit to the pv (like dropping off of a roof) that would not be covered under the warranty. repairing it is nearly impossible, but you've nothing to lose by trying as it is scrap otherwise. $50 good deals on 4 of them and out $50 on one of them. if you need all 5 pvs then you should buy another pv even if you manage to get that 5th one working as it is compromised and unreliable.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: How to repair a 75 watt panel?
    mike90045 wrote: »
    When you find the magic repair goop, let us know.

    I've torn the backing on some 30+ year old french Photowatt panels (@10 years ago)as well as on one of my 3 year old Evergreen Panel when installed. (using and electric screw driver on cheap SS bolts bought on Amazon and caught a burr, wrench hit panel and torn the tedar)

    I used liquid electrical tape on both repairs, I'm actually more happy with the repair on the old Photowatt panels, as I recall the liquid electric was also a tool dip.

    I think I used the branded Liquid Electrical tape and it was a bit more foamy than solid.

    I haven't checked the Evergreen lately but it was fine last time I checked, maybe8 months ago, the Photowatt panels the repair was done about 10 years ago when I moved to Missouri, the backing has seperated over the years in some areas, but not where the repair was made, when I took them down the same 8 months ago.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: How to repair a 75 watt panel?

    The fact that it is maintaining current would suggest a cell connection is opening and bypass diode is taking over. Sounds like that panel has two bypass diodes, one bypass diode for half of the cells. Can not imagine how a short could be causing that effect.

    Look at each tabbing connections on each cell. See if there is any delamination visible near a tab connection point. Then hope you are very lucky on being able to solder a jumper across bad connection. Cover back up with 'Marine Goop" sold in Lowes or Home Depot.
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: How to repair a 75 watt panel?

    I though of another possible way to find failure point.

    A 12v panel with 36 cells should have a Voc of about 22-23 vdc at 25 deg C.

    With two 12 v batteries in series, and a 0.5 to 1.0 ohm power resistor in series with batteries, you will be forcing between 2 and 4 amps through the panel backwards with no damage to the cells.

    In a dark room, you may be able to see the arcing at the failure point while flexing the panel at point you mentioned.
  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    Re: How to repair a 75 watt panel?
    RCinFLA wrote: »
    In a dark room, you may be able to see the arcing at the failure point while flexing the panel at point you mentioned.

    Amazing! How do you do it! Almost wants me to wreck a panel to see it.;)
  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    Re: How to repair a 75 watt panel?

    If you want to be fancy, get an IR camera. It should show up like a fire fly.

    What was the model of that Sony camcorder that showed women's undies? ;)
  • Kamala
    Kamala Solar Expert Posts: 452 ✭✭
    Re: How to repair a 75 watt panel?

    I think it was Kirlian.

    Or something out of the back pages of a comic book.

    Might be wrong.:confused:
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: How to repair a 75 watt panel?

    Most digital cameras are more sensative to near IR spectrum.

    To test, if you have a pocket digital with an electronic display on the back (electronic viewfinder) you can point a remote control at it and see the remote working usually. Not like a laser beam, point the camera and the remote at each other...lol
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • BilljustBill
    BilljustBill Solar Expert Posts: 219 ✭✭✭
    Re: How to repair a 75 watt panel?
    Photowhit wrote: »
    Most digital cameras are more sensative to near IR spectrum.

    To test, if you have a pocket digital with an electronic display on the back (electronic viewfinder) you can point a remote control at it and see the remote working usually. Not like a laser beam, point the camera and the remote at each other...lol

    Thanks to each of you for all your repair insights. I had to try what Photowhit suggested about checking for IR with a digital camera. I have an older 7 Meg, Panasonic LUMIX digital camera. The IR port for the TV remote had a nice pinkish-red glow when seen through the camera's rear picture screen. Looking at the same port with bare eyes just seems to be dark...

    I had to laugh!! Learning something new and how to apply it to daily problems keeps my interest going! Thanks.

    Bill
    Bill
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: How to repair a 75 watt panel?

    I sincerely doubt that a digital camera will detect heat from a high resistance point in the panel.

    The real Heat sensing type cameras setup to detect "long wave" IR. The standard digital camera is not capable of detecting long wave IR and there is also an IR Filter in these cameras to prevent IR from changing colors in the final picture.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: How to repair a 75 watt panel?

    I had a Siemens 55 watter that quit. What I discovered was a solder join were the string wiring joins the terminals in the J box. You might look carefully at the J box connections.

    Tony