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  • barneyfoot
    Junior Member
    • Jun 2020
    • 13

    Kyocera panels from 2006, could they have degraded by 25% in 14 years?

    Brand new, the output capacity of my panels is 8100 W. I have 2 inverters and 1 of them has failed so I'd expect to see that my system is producing somewhere between 3700 and 4k W.

    Instead, at noon on full sun day my Xantrex display said I'm producing 2995 W.

    My panels appear to be facing due South and are mounted at 45% angle in Denver area.

    Is it possible that they really are only producing 75% capacity? Sadly I never noticed what I was producing when both inverters were working full strength. Only started monitoring now that 1 of them has broken

    Thanks!
  • bcroe
    Solar Fanatic
    • Jan 2012
    • 5203

    #2
    My experience is that the Denver area has cool, very clear skies, near ideal for PV
    solar. My guess is that the working system is not in perfect working order, beyond
    14 years aging. I am guessing that system has at least 2 strings of panels to reach
    4KW. Here I would go out at best sun with my clamp on DC ammeter and see if the
    operating strings are producing identical current, or some problem is degrading one.
    Do check the DC voltage and current into the inverter, and compare that with predicted
    at your temperature.

    Here with 2 inverters, one glance reveals if they are delivering identical power. They
    usually agree within a couple percent, a fault is quite obvious. good luck, Bruce Roe

    ClmpOnAmm.JPG
    Last edited by bcroe; 08-04-2020, 12:12 PM.

    Comment

    • J.P.M.
      Solar Fanatic
      • Aug 2013
      • 14939

      #3
      The short ans. to your question is probably yes.

      According to PVWatts, on a clear day at around noon an unshaded south facing array in Denver ought to be producing ~ 725 -750 W/installed STC kW for a new array.

      BTW, most any PV system will only produce its STC rated output in cold(er), clear weather.

      Run PVWatts, use 10 % system losses, use the hourly output option and look for dates around this time of year with high output.

      Comment

      • barneyfoot
        Junior Member
        • Jun 2020
        • 13

        #4
        Originally posted by J.P.M.
        The short ans. to your question is probably yes.

        According to PVWatts, on a clear day at around noon an unshaded south facing array in Denver ought to be producing ~ 725 -750 W/installed STC kW for a new array.

        BTW, most any PV system will only produce its STC rated output in cold(er), clear weather.

        Run PVWatts, use 10 % system losses, use the hourly output option and look for dates around this time of year with high output.
        Interesting. PVWatts says 30% loss when I consider 14 years age and some shading which I do have. Had to order a voltmeter with loop and when that arrives I can confirm for sure. Thanks.

        Comment

        • J.P.M.
          Solar Fanatic
          • Aug 2013
          • 14939

          #5
          Originally posted by barneyfoot

          Interesting. PVWatts says 30% loss when I consider 14 years age and some shading which I do have. Had to order a voltmeter with loop and when that arrives I can confirm for sure. Thanks.
          You're welcome. That PVWatts modeled # was for a new system. If reasonably correct, it'll mean with the numbers you provided, you're doing pretty good.

          Check voltage and current under full sun.

          Comment

          • barneyfoot
            Junior Member
            • Jun 2020
            • 13

            #6
            Turns out my capacity is actually 7800 W, and just now saw my meter read 3300 W (with 1 broken inverter) so I think my panels are doing just fine. Thank you JPM and bcroe.

            Comment

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