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  • Bobup
    Junior Member
    • Feb 2022
    • 15

    #1

    Peak output vs actual

    Solar Edge system
    15 300kw panels plus 4 400kw panels
    The 15 facing south with no obstruction
    The 4 panels are facing East with no obstruction
    = 6100kw ? potential
    Every day the app peaks at 5kw with production around 22kwh
    so my question is...why does it peak at 5kw
    TIA Bob
  • J.P.M.
    Solar Fanatic
    • Aug 2013
    • 15036

    #2
    For starters, those are "W", not "kw".
    "kW" = 1,000 W.
    You have a 6.1 STC kW system.
    The most you will get from either portion of the system is about 0.85 of the STC output for that portion.
    Those peaks will come at different times due to different orientations of the larger and smaller portions of the system.
    Given two different array orientations, that 5 kW peak output sounds about right, depending on your location and weather and maybe happening slightly before solar noon (which is most likely not at 12:00 noon civil time).
    Download a free copy of "Solar Power Your Home for Dummies" for explanations of the above.
    Then download and get familiar with a user-friendly design program called "PVWatts" which will model your system and provide you with information about expected system performance.
    After the self-education and homework, come back and ask questions to fill in any knowledge gaps your self-education creates.

    Comment

    • davidcheok
      Solar Fanatic
      • Dec 2022
      • 100

      #3
      Maybe you should list out the nameplate output for the inverter first?

      Comment

      • solar pete
        Administrator
        • May 2014
        • 1839

        #4
        Originally posted by Bobup
        Solar Edge system
        15 300kw panels plus 4 400kw panels
        The 15 facing south with no obstruction
        The 4 panels are facing East with no obstruction
        = 6100kw ? potential
        Every day the app peaks at 5kw with production around 22kwh
        so my question is...why does it peak at 5kw
        TIA Bob
        Sounds like you have a 5kW inverter mate

        Comment

        • J.P.M.
          Solar Fanatic
          • Aug 2013
          • 15036

          #5
          Originally posted by solar pete

          Sounds like you have a 5kW inverter mate
          And I'd suggest if the other provided information is reasonably correct, that's probably about the right size.

          Comment

          • Bobup
            Junior Member
            • Feb 2022
            • 15

            #6
            So here is a pic of the inverter label.
            if I'm reading this correctly...it has a max output of 5000w
            so my system has the potential to do more , 6100w, but the inverter is holding it back.
            so the next question(s) is, is it worth upgrading the inverter? And can I do it or is paying someone else the better choice?
            Thanks again for the insight and knowledge that is shared here, Bob
            Attached Files

            Comment

            • J.P.M.
              Solar Fanatic
              • Aug 2013
              • 15036

              #7
              Originally posted by Bobup
              So here is a pic of the inverter label.
              if I'm reading this correctly...it has a max output of 5000w
              so my system has the potential to do more , 6100w, but the inverter is holding it back.
              so the next question(s) is, is it worth upgrading the inverter? And can I do it or is paying someone else the better choice?
              Thanks again for the insight and knowledge that is shared here, Bob
              You are partially correct. Your inverter is limiting your maximum power output to 5kW.
              However, it's pretty unlikely your system will ever achieve its 6.1 kw STC rating except under unusual conditions of high irradiance or if extra irradiance hits the arrays either from bright surroundings of the intentional placement of highly reflective materials.
              In any case, your inverter is likely limiting your output, but that doesn't mean it undersized because the most you're likely to get out of the array is something like 5 kW or so and that's likely to happen only a few hours of the year., if that much.
              Read the Dummies book for reasons why.

              Comment

              • Bobup
                Junior Member
                • Feb 2022
                • 15

                #8
                Dummies book has been ordered...awaiting it's arrival. TY

                Comment

                • J.P.M.
                  Solar Fanatic
                  • Aug 2013
                  • 15036

                  #9
                  Originally posted by Bobup
                  Dummies book has been ordered...awaiting it's arrival. TY
                  NOMB but FWIW, I'd cancel that order.
                  What you need is in the 1st ed. and it's a free PDF download for some snooping around on the net as is PVWatts. Just read ALL the help screens before you do any runs. and get the inputs as close to reality as possible. You'll need separate runs for each array orientation. use the hourly printout option , then add the results together for combined output on one of the spreadsheets.

                  Comment

                  • azdave
                    Moderator
                    • Oct 2014
                    • 794

                    #10
                    Originally posted by Bobup
                    if I'm reading this correctly...it has a max output of 5000w
                    so my system has the potential to do more , 6100w, but the inverter is holding it back.
                    so the next question(s) is, is it worth upgrading the inverter?
                    No. If you upgrade to a 6000W inverter now, you would likely never recover what it will cost to purchase and install it, even if you sold the used 5K inverter to someone else to help you recoup some of the upgrade costs.

                    The small amount of energy you are not converting only occurs during the peak of the solar day and only when conditions are perfect. That little bit extra you might collect with a new inverter will never be significant enough to matter compared to what you will spend to get it. Your 5K inverter appears to be working as planned and again, there is only a brief time period in the day where a 6K inverter could take full advantage of what your panels output during that daily peak production that occurs around solar noon. As your panels age, and they naturally lose some efficiency, you might not see any clipping. I believe a 5K inverter is a perfect choice now and in the future. In my opinion, your panels and inverter were chosen properly by the installer. The cost difference to install a 6K inverter back when the system was new probably would have moved the ROI point several more years down the road.

                    Dave W. Gilbert AZ
                    6.63kW grid-tie owner

                    Comment

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