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Posted

I took this picture about 16:35. The shadow that now partly covers 2 panels starts becreeping the array about 16:00.

AIUI the other three panels will now drop their output to that of the two that the shadow falls on. Is that correct? 

20200822_164112_(1).jpg

Posted
3 hours ago, Bobster said:

AIUI the other three panels will now drop their output to that of the two that the shadow falls on. Is that correct? 

I have 3S2P and did a test some months back where I threw a blanket over one panel (If i recall correct) only that string with the blanket were effected and the other two strings were not effected. I did the test because my fireplace chimney threw a small shadow on one panel, but my conclusion was the chimney effect was minimal.

The result might be very different with a systems that have only one string in series.

Posted
12 hours ago, Bobster said:

AIUI the other three panels will now drop their output to that of the two that the shadow falls on. Is that correct? 

My understanding is no. The voltage of the two shaded panels will drop, possibly to zero, but the diodes in the panels will prevent them going negative. The other panels will in effect provide full output, unaffected by the shadow on two panels. By 16:00, your output will be fairly low anyway. Your output should drop to about 4/6 = ⅔ of what it would have been.

I assume that your other string is connected to a different MPPT. So it will also be completely unaffected.

Posted
11 hours ago, Coulomb said:

My understanding is no. The voltage of the two shaded panels will drop, possibly to zero, but the diodes in the panels will prevent them going negative. The other panels will in effect provide full output, unaffected by the shadow on two panels. By 16:00, your output will be fairly low anyway. Your output should drop to about 4/6 = ⅔ of what it would have been.

I assume that your other string is connected to a different MPPT. So it will also be completely unaffected.

Yes, I didn't expect to be generating a lot at 16:00. 

This array faces northish. The other 6 panels, on a separate MMPT, are 90 degrees to this, so eastish. 

Posted
20 hours ago, Gerrie said:

I have 3S2P and did a test some months back where I threw a blanket over one panel (If i recall correct) only that string with the blanket were effected and the other two strings were not effected. I did the test because my fireplace chimney threw a small shadow on one panel, but my conclusion was the chimney effect was minimal.

The result might be very different with a systems that have only one string in series.

Thanks. I have 6 panels on each string. I think. Certainly 6 per MMPT. 

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