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55% less output from 2 out of 14 panels grouped in the same location

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  • 55% less output from 2 out of 14 panels grouped in the same location

    Hello Experts!

    I have 2 panels shown below towards the top right of the picture that are producing significantly lower output than the ones directly below. The third arrow/panel on the bottom is an anomaly as an adjacent pipe is casting a shadow.

    My provider is stating that the 2 panels are strung together with the set of panels located on the left side of the picture and therefore will not produce the same output. These are Panasonic 330w panels with micro-inverters. My understanding was that by choosing micro-inverters, I would not be subject to the output constraints of any other panel. Could someone explain why this is occuring?

    My primary concern is that when all the panels produce about 5Kw, there is a momentary drop in output. This occurs every day when reaching 5KW. Solaredge replaced 1 micro-inverted with no change in behavior. Total is a clear day with no cloud cover and an outdoor temperature of 70F.

    Thank you!

    Panel total output 031919.png



    Panel output 031519 11am.png
    Attached Files

  • #2
    First and formost you do NOT have micro inverters, you have solaredge optimizers.


    the bigger concern is the pv module 1.2.2 which is always lower and not shadowed in any way may be a failed PV module, not the optimizer but the pv module.

    as for 1.1.2 and 1.1.9, the installer did a poor job laying them out, they should have included a few more PV modules from the south array in the west array to prevent this.

    It looks like you have 6.93kw on a 6kw inverter ( very minor clipping)
    Last edited by ButchDeal; 03-15-2019, 08:13 PM.
    OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

    Comment


    • #3
      I have a SolarEdge setup with a total of 24 panels. 18 South facing, 4 West facing and 2 East facing. The 4 West facing are strung together with 8 South facing. The 2 East facing are strung together with 10 South facing. 12 panels on each string with varying orientations.

      All my panels perform as they are supposed to with no loss in productivity. All of my South facing panels produce within a couple of percentage points of others, as do the West and East panels. All produce within a couple percent of the others with the same orientation. I have no shading issues. As Butch said, maybe there are requirements when stringing panels from different orientations. I do not know what there are, but it looks like I got lucky in how I did mine.

      If I were to have installed this system. I probably would have strung half of the 7 west facing panels with half of the South facing panels. This will probably eliminate the problem. However, this is more just a guess.

      Second, I think Butch misunderstood that panel 1.2.2 is the one that is shaded and there is likely nothing wrong with this panel.

      I do not have any bump in my power curve at 5,000 watts, however I have the 10,000 watt inverter. Is this bump just one day or every day. My daily power curve can look like a nice bell curve on days with no clouds and look like a jagged mountain top on cloudy days. The 5.000 bump explanation from the installer sounds like complete misinformation to me.
      Last edited by John_Dumke; 03-17-2019, 12:49 PM.

      Comment


      • #4
        Panel total output 031819.pngPanel total output 031619.png

        Hello ButchDeal and John_Dumke,

        @ButchDeal: Your correct with the equipment in that I do have optimizers and not micro-inverters. Concerning the top solar panel, the provider moved the panel to the correct position on the roof and updated the diagram.

        @John: I have a SolarEdge 7600HD inverter. The bump at 5000W occurs every day. Some days more extreme than others. Attached are the last 2 days as an example under clear skies.

        My plan is to put in a support ticket with SolarEdge and listen to what they have to say. Hopefully they will recognize the issue and dispatch replacement parts.

        Lastly, Is this something I really need to worry about for long term reliability and power generation?

        Thank you for the feedback.


        Comment


        • #5
          Originally posted by greendaddy View Post
          [
          Lastly, Is this something I really need to worry about for long term reliability and power generation?
          From a power production standpoint this little hitch at 5,000 watts is nothing to worry about. Might this symtom be an indication of some underlying problem with the hardware? Maybe..... Maybe not. My power curve is rarely bell curve smooth. However there isn't any consistent "glitch". My very uneducated gut feel is that you are worrying about nothing.

          Let us know what SE says.

          What about restringing the panels to eliminate the two upper week producers? This would be my concern.

          Comment


          • #6
            It might be not a Power problem , but a timing issue ...

            Maybe some pipe at that time of day casts shadow over one
            more of the panels ; for example before one panel had
            shading , now at around 11:45 o'clock the shadow cut
            into a second panel , and the optimizer of that panel
            might not be able to adjust much , because either being
            some double-oprimizer or being of wrong watt size .

            Comment


            • #7
              Originally posted by greendaddy View Post
              Panel total output 031819.pngPanel total output 031619.png

              Hello ButchDeal and John_Dumke,

              @ButchDeal: Your correct with the equipment in that I do have optimizers and not micro-inverters. Concerning the top solar panel, the provider moved the panel to the correct position on the roof and updated the diagram.

              @John: I have a SolarEdge 7600HD inverter. The bump at 5000W occurs every day. Some days more extreme than others. Attached are the last 2 days as an example under clear skies.

              My plan is to put in a support ticket with SolarEdge and listen to what they have to say. Hopefully they will recognize the issue and dispatch replacement parts.

              Lastly, Is this something I really need to worry about for long term reliability and power generation?

              Thank you for the feedback.

              If that bump occurs (and is most noticeable on clear days), and while not suggesting that jibes with the panel output map, when something such as that glitch on the graph occurs, it's most often shading of some sort - maybe a stink vent or some small nearby or larger but farther away structure (a street light, etc. ?) but in any case permanent structure. Does the blip come/go, get larger/smaller, or change relative curve location with the seasons ? If it shows up most noticeably on clear days but at about the same relative location on the graphs, I'd suggest whatever is going on is perhaps at least partly due to some f(solar position) and some shading relative to the array or some part(s) of it.

              The fix you write of happened after the 03/16 graph but before the 3/18 graph ? The two graphs show daily output was maybe a little less after the fix. It's hard to get real analytical here but it looks like the sky on either day had no real definable clouds (cumulus type for example), but maybe the 18th was a bit less "clear" (and or high clouds/haze ??) as evidenced by the lower daily output but similar curve shape and less area under the production curve for the 18th. Also, the less pronounced blip would indicate less clear skies. hard to say. If so, and after the fix, it looks like some "glitch" is still there, but less pronounced. Don't know how correct my eyeball is, but it may be that the fix corrected most of the problem, hardware or otherwise, but maybe not all of it. Anyway, it looks to me like the notch is still there. Maybe a street light nicking a spot on the array ? Or a stink vent ?

              If the glitch is due to shade - at least/maybe partially - a less than clear day would have less difference in irradiance between shaded and unshaded areas. That may be the reason for the less prominence of the glitch on the 18th.

              Given the relatively large difference in output of the 3 panels vs. the other panels, I'm wondering if the fix so far corrected two panels' output, but the shading is still a problem somehow. Maybe the glitch in the graphs and the lower output from the 3 bad actors are unrelated, or if related, it's a weak/secondary link, but maybe not.

              If there's a vent and it's visible next time the sun shines, I'd get after it with a saw and call it done.

              Good luck.

              Comment


              • #8
                Hello,
                Below I have added a picture of the South roof depicting one of the panels that is being shaded. The two at the upper left side of the picture are the ones under performing and are tied to a set of panels facing West. The remaining screen shots are from a video I took of the SolarEdge inverter. I've numbered them from Frame1 to Frame 7 hoping to convey that when reaching about 5156W, the output reduces to 3301W then builds back up again. This oscillation repeats for 5-10 minutes varying at the lower range.

                @JPM. the pictures are after repair where one of the optimizers was replaced. However, I believe they replaced the wrong unit as the diagram was incorrectly layed-out. You are correct that the glitch is there in both picture but the amounts vary.

                john, perhaps its not something I should worry about and instead focus on the two under performing panels as you suggest



                img_1540944968746_1540945760852.jpgRoof showing pipe shading 1 panel
                1.jpgFrame1, Power 5103W 2.jpgFrame2, Power 5156W
                3.jpg Frame3, Power 45834.jpg Frame4, Power 4191
                5.jpgFrame5, Power 3727 6.jpg Frame6, Power 3301
                7.jpg Frame7, Power 3995
                Attached Files

                Comment


                • #9
                  Originally posted by greendaddy View Post
                  Hello,
                  Below I have added a picture of the South roof depicting one of the panels that is being shaded. The two at the upper left side of the picture are the ones under performing and are tied to a set of panels facing West. The remaining screen shots are from a video I took of the SolarEdge inverter. I've numbered them from Frame1 to Frame 7 hoping to convey that when reaching about 5156W, the output reduces to 3301W then builds back up again. This oscillation repeats for 5-10 minutes varying at the lower range.

                  @JPM. the pictures are after repair where one of the optimizers was replaced. However, I believe they replaced the wrong unit as the diagram was incorrectly layed-out. You are correct that the glitch is there in both picture but the amounts vary.

                  john, perhaps its not something I should worry about and instead focus on the two under performing panels as you suggest



                  img_1540944968746_1540945760852.jpgRoof showing pipe shading 1 panel
                  1.jpgFrame1, Power 5103W 2.jpgFrame2, Power 5156W
                  3.jpg Frame3, Power 45834.jpg Frame4, Power 4191
                  5.jpgFrame5, Power 3727 6.jpg Frame6, Power 3301
                  7.jpg Frame7, Power 3995
                  I'll be interested to see/hear/read about any resolution/findings.
                  Thank you for the response.

                  Comment

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