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Parallel string voltage with shading

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I'm doing a 6S2P east/west split. 

I'm thinking about voltage here not current. By midday the east string will be half shaded. What happens to the voltage of the west string? 

If the east string is a lower voltage will it pull down the west string voltage? 

7 minutes ago, Chris_S said:

I'm doing a 6S2P east/west split. 

I'm thinking about voltage here not current. By midday the east string will be half shaded. What happens to the voltage of the west string? 

If the east string is a lower voltage will it pull down the west string voltage? 

Yes big time as indicated low voltage on both strings=very low output. 

Correct me if I'm wrong. 

  • Author
10 minutes ago, Scorp007 said:

Yes big time as indicated low voltage on both strings=very low output. 

Correct me if I'm wrong. 

I mean lower voltage on 1 string and full voltage on the other. 

Basically 3 panels on the east string get half shaded after noon. But shaded panels still produce voltage and not current so I'm not sure. 

29 minutes ago, Chris_S said:

I'm doing a 6S2P east/west split. 

I'm thinking about voltage here not current. By midday the east string will be half shaded. What happens to the voltage of the west string? 

If the east string is a lower voltage will it pull down the west string voltage? 

I read a document on using an east/west split on one MPP, apparently it does work. 

Will see if I can find the thread on the for8um that was talking about it. 

  • Author
3 minutes ago, Sc00bs said:

I read a document on using an east/west split on one MPP, apparently it does work. 

Will see if I can find the thread on the for8um that was talking about it. 

I'm thinking that possibly the higher voltage string will raise the voltage on the shaded string. Not the other way round. 

24 minutes ago, Chris_S said:

My 8S string still produces over 350V with half the panels in shade. Just low current

You might be right. I have just checked when my string has some shade and the voltage does indeed stay high due to the bypass diodes. See picture below. Voltage in blue. 

So my previous post is totally wrong. 

Shaded cells still produce a voltage if it gets light even in shade. 

IMG_20230714_095224.thumb.jpg.383bb8f3354422ede5b0e32db8ee6412.jpg

Edited by Scorp007

  • Author
4 minutes ago, Scorp007 said:

You might be right. I have just checked when my string has some shade for a short period and the voltage does indeed stay high due to the bypass diodes. 

So my previous post is totally wrong. 

Shaded cells still produce a voltage if it gets light even in shade 

Yes. And in the parallel case I think the higher voltage on one string could force the bypass diodes on the shaded string to close. 

Edited by Chris_S

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