Solar Panels lose efficiency?

System
System Posts: 2,511 admin
I understand that panels lose efficiency over time.

Does this hold true even for panels that are in storage?.... or does it only hold true for panels that are exposed to sunlight.

Thanks

Comments

  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Solar Panels lose efficiency?

    Degradation is due to sunlight.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Solar Panels lose efficiency?

    Even though panels may lose efficiency over time, the result is very slight and quite small in the real world. I have panels that have been in the elements for over 20 years and still produce near name plate rating under ideal conditions.

    Tony
  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Solar Panels lose efficiency?

    Thin cell panel loss efficiency over 7 years (about 20%) Mono/Poly cells do not. We measure d a panel made in 1981 (big bucks back then) cleaned the glass, it was within 1% at STC.

    They DO NOT degrade due to sunlight. These panels degrade by the oxidation of the doping. That is why the manufactures offer such good warranties on these type of panels.
  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    Re: Solar Panels lose efficiency?

    NREL says that crystaline panels degrade because of UV exposure, see paragraph 3, page 3:
    http://www.docstoc.com/docs/55853213/Degradation-Analysis-of-Weathered-Crystalline-Silicon-PV-Modules
  • System2
    System2 Posts: 6,290 admin
    Re: Solar Panels lose efficiency?

    Hmmm, not sure why my original post appears at the bottom here.

    Thanks for the info, though!

    I asked because I was thinking of getting a very small solar system. One suitable for long term camping or emergency use to charge the basics.

    With that, this stuff would be stored rather than exposed to the sun.

    I assumed that it was sun exposure that degrades panels, but my assumptions are often wrong!:blush:

    Thanks
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: Solar Panels lose efficiency?

    I have some French Photowatt panels made in the 70's that produced with in 80% of the current measured via trimetric meter, when I took them out of service 3 years ago. I don't know about the voltage as I used a PWM charge controler.

    As to your post being at the bottom, you have your prefences setup to have the newest messages first. I do as well and can't recall how to switch it back, as the other forums I post on do not offer this feature.

    Perhaps a Mod can help us both out.
    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.
  • mr.radon
    mr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: Solar Panels lose efficiency?

    stephendv - great link! Great article.

    Page 4 lists the possible causes. They mention 4, 2 related to encapsulation. Would be interesting to know if in the last 10 years the encapsulation has improved to mitigate some of these issues.

    Wow, this has dispelled my confidence that my poly panels will not degrade much over time. I should have asked how long that panel we tested was in storage compared to being outside making power...
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Solar Panels lose efficiency?

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