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Why is this panel underproducing in the morning and afternoon?


Well-Known Member
Feb 28, 2015
Merced, CA
There's one panel in my setup that underproduces in the morning and the late afternoon every day. During the middle of the day it's output is right there will all other 24 panels. But at the ends of the day it's WAY under. It's not shading issue. All the SE screen shots below are when the panel is in full sun with no panels having any shading at all.

At noon:

Screen Shot 2021-01-21 at 12.06.30 PM.png

At 2:45. You can see panel 3 is quite a bit lower relative to others:

Screen Shot 2021-01-21 at 12.06.20 PM.png

At 3:45 in the afternoon no panels have shading and every panel is between 118 and 130 watts except number 3 which is at 34 watts. Is this the panel or optimizer? What would cause it to produce normal levels in the middle of the day but not the ends of the day?

Screen Shot 2021-01-21 at 12.06.58 PM.png


  • Screen Shot 2021-01-21 at 12.06.42 PM.png
    Screen Shot 2021-01-21 at 12.06.42 PM.png
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Nov 2, 2017
Berkeley, CA
That's got to be a defect, have the installer come replace the panel and its optimizer. They won't want to make two trips, and they can figure out at their leisure which one is defective.

Cheers, Wayne

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