What are the people opinion on these PV production results?

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  • GoingElectric
    Solar Fanatic
    • Jun 2022
    • 120

    What are the people opinion on these PV production results?

    This is an installation done last year, finally connected in late June (long sad story here)

    I saw some big variations in summer, but it is much more pronounced now.
    Enphase MI installation.

    IGNORE: the nearly black ones, they are north facing (I told them bad place, but was ignored)
    NO: The array is not exactly as installed but close enough
    YES: the gaps you see on left side are for vents.

    Thoughts on panel performance?

    All the blue ones located E, S, and W are
    Aptos DNA-120-MF26-370W
    Array production 18 Dec 23.png
    (FYI the black ones (north facing) added later are MSOLAR: TXS6-440144BB, 440W. Yes, I know, its a very sad case)

    Yes, massive array, could not fit it all and still be readable.

    Attached Files
  • Mike 134
    Solar Fanatic
    • Jan 2022
    • 393

    #2
    I'd plug in each roof plane into this calculator and see how yours compares.

    PVWatts Calculator (nrel.gov)

    Comment

    • chrisski
      Solar Fanatic
      • May 2020
      • 553

      #3
      Some of these panels are making 3x others in the same plane. Is there shading involved?

      North facing panels are bad, but you picture at the shortest days of the year with these showing 1/10th production of the correctly mounted ones. In the summer I’m assuming much better production.

      Comment

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

        #4
        As Mike suggests, plug each roof plane into PVWatts, but only do so after you understand how the model works and its limitations. Most all you need to know about your array's performance lies in the model's help screens. More than you need to know can be found in the model's bibliography. All you can possibly want to know about residential PV is within your own reach and initiative. It's mostly low hanging fruit.

        Without more information it's not possible to give an informed opinion about performance of your system, particularly since the cartoon is only for one day which means little in terms of expected performance vs. modeled performance (which seems to be what you're looking for).

        You've been around here for about 18 months or so. For more insight as to why that is, if you haven't done so already, start (but don't finish there) by reading all the information that comes with the PVWatts model.
        Do that and besides learning a lot that you need to know, you'll understand why it's not possible to give intelligent responses with only the info you've provided so far.

        Take what you want of the above. Scrap the rest.
        Last edited by J.P.M.; 12-28-2023, 12:24 PM.

        Comment

        • GoingElectric
          Solar Fanatic
          • Jun 2022
          • 120

          #5
          Originally posted by Mike 134
          I'd plug in each roof plane into this calculator and see how yours compares.

          PVWatts Calculator (nrel.gov)
          I am focused on individual panel variations.

          Originally posted by chrisski
          Some of these panels are making 3x others in the same plane. Is there shading involved?

          North facing panels are bad, but you picture at the shortest days of the year with these showing 1/10th production of the correctly mounted ones. In the summer I’m assuming much better production.
          There is effectively NO shading. (I estimate only 4 might have a little shading from vents)

          I will upload satellite image.

          Not concerned about north ones (different panels, different install)


          Originally posted by J.P.M.
          As Mike suggests, plug each roof plane into PVWatts, but only do so after you understand how the model works and its limitations. Most all you need to know about your array's performance lies in the model's help screens. More than you need to know can be found in the model's bibliography. All you can possibly want to know about residential PV is within your own reach and initiative. It's mostly low hanging fruit.

          Without more information it's not possible to give an informed opinion about performance of your system, particularly since the cartoon is only for one day which means little in terms of expected performance vs. modeled performance (which seems to be what you're looking for).

          You've been around here for about 18 months or so. For more insight as to why that is, if you haven't done so already, start (but don't finish there) by reading all the information that comes with the PVWatts model.
          Do that and besides learning a lot that you need to know, you'll understand why it's not possible to give intelligent responses with only the info you've provided so far.

          Take what you want of the above. Scrap the rest.
          Yes, I should have added more. Was in a rush, so did half-ass post. Apologies.

          ​​​​​​​

          Comment

          • GoingElectric
            Solar Fanatic
            • Jun 2022
            • 120

            #6
            Here are more details:
            The array panel production was on a perfectly cloudless day.
            Here is the production curve.
            Array Total production 18 Dec 23.png

            This is Layout (does NOT include the NORTH panels, that is different install)
            Also the app layout is not exact to installation
            House roof arry plan.png
            House roof satalite image.png

            For comparison, this is summer, 26 August 2023, also a PERFECT day.
            Array production 26 Aug 23.png

            I am wondering about the variations in panels, even in areas that are seemingly free of shade.
            Quality variation of Aptos DNA-120-MF26-370W panels?

            Now I am thinking the installer did not correctly map the panels to image. Does Enphase have a way to ID each inverter location, or is that all manual?


            As for the install, the advice I gave about install issues was unheeded, especially the north panels added later (at least in summer they are useful)
            Last edited by GoingElectric; 12-28-2023, 02:14 PM.

            Comment

            • chrisski
              Solar Fanatic
              • May 2020
              • 553

              #7
              “Quality variation of Aptos DNA-120-MF26-370W panels?….”

              I can’t speak to the spec data allowable output difference for your panels, but my Q-Cell are either 5% or 10% difference in laboratory conditions.

              I saw a separate post on a different board about optimizers. The optimizer showed a +/-10% difference for each panel.

              Perhaps the difference in output is more of an enphase thing compared than a panel thing.

              Have you ran the three or four different planes through PV watts to see what the expected production is? 60.4 kWh seems a respectable amount.

              ———
              Thanks for including data on summer for winter production for your local area.

              Here, I see quite a few north facing panels. It’s nice to see the data for a day of winter production with next to nothing produced, and the summer production with each north facing panel producing slightly less than an ideally placed panel. So, for here, although not ideal, North facing panels could be good for Summer air conditioning when electric bills are 5 to 10 times what they are in our temperate winter.

              Comment

              • scrambler
                Solar Fanatic
                • Mar 2019
                • 500

                #8
                You definitely first need to verify that the layout of the panel matches reality (that panels are in the location they appear).
                I don't know any way to do that other than manually by masking these panels one by one, with a heavy cloth or cardboard, and check the production, assuming you have real time monitoring allowing you to see each panel production within a minute or two.

                Once you are sure you have a layout that matches reality, if you still have major difference between two panels in the same plane AND without any shading, the next thing to check is if that difference is consistent throughout the day, or if it only happens during some period.

                If it is consistent throughout the day, then there is a problem with the panels or their optimizer / micro inverter is they use one.

                Comment

                • Mike 134
                  Solar Fanatic
                  • Jan 2022
                  • 393

                  #9
                  As Scrambler said you'll have to manually check that the diagram matches reality. Each inverter under the panels will have a unique serial number that also shows up on your screen but again you need to physically read it on the roof to verify location.

                  How often does Enphase cloud update the production data? - Support | Enphase

                  Comment

                  • GoingElectric
                    Solar Fanatic
                    • Jun 2022
                    • 120

                    #10
                    Originally posted by scrambler
                    You definitely first need to verify that the layout of the panel matches reality (that panels are in the location they appear).
                    I don't know any way to do that other than manually by masking these panels one by one, with a heavy cloth or cardboard, and check the production, assuming you have real time monitoring allowing you to see each panel production within a minute or two.

                    Once you are sure you have a layout that matches reality, if you still have major difference between two panels in the same plane AND without any shading, the next thing to check is if that difference is consistent throughout the day, or if it only happens during some period.

                    If it is consistent throughout the day, then there is a problem with the panels or their optimizer / micro inverter is they use one.
                    For sure the Enphase diagram does not match the print diagram, but I am now leaning that the map is not at all accurate on which panel is which, not just layout.
                    Panels + MI are working just fine.

                    So if it has to be manually entered, then the map is likely entirely wrong (except the NORTH panels, those are likely correctly mapped and located.


                    Thanks for feedback everyone!

                    Comment

                    • chrisski
                      Solar Fanatic
                      • May 2020
                      • 553

                      #11
                      You could fly a drone over it to shade a panel. It does not need to be right next to it, only to shade it.

                      i would not want to climb up on a roof and cover the panels to see which is which. Especially if it is getting 60kwh on a good day.

                      Comment

                      • GoingElectric
                        Solar Fanatic
                        • Jun 2022
                        • 120

                        #12
                        Originally posted by chrisski
                        You could fly a drone over it to shade a panel. It does not need to be right next to it, only to shade it.

                        i would not want to climb up on a roof and cover the panels to see which is which. Especially if it is getting 60kwh on a good day.
                        Well, even if I do want to put effort in, still need to edit the diagram, but do not have the access and software.

                        Comment

                        • scrambler
                          Solar Fanatic
                          • Mar 2019
                          • 500

                          #13
                          You should be able to ask your installer for access.
                          Even if you are not going to put in the effort, you should request installer access so you are not stuck when they disapear....

                          Comment

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