[RE-wrenches] Voltage Degradation with Uni-Solar laminate

[Luke Christy]

Jay,
the 71V I measured was the array VOC. 
Accessing the wiring for individual strings is fairly difficult as the combiners are high up in a hot attic. I didn't have a lot of time on site the day I observed this problem, so didn't gather as much information as I could have otherwise. 

A re-wire for more voltage looks like the solution.  With 8 modules in series, allowing for a wintertime extreme minimum temp of -30C is really going to drive the VOC up there. That looks like Classic 250 territory for a long-term solution
 
-Luke


As   
On May 31, 2015, at 1:23 PM, jay peltz <jay.peltz at gmail.com> wrote:

HI Luke,

To add here.  I'm unclear if you have measured each string or the whole array at 71v.  
I would check each string for voc/isc.  

And then if they are consistent, I agree that putting 2 strings in series with a new controller might help out.  
You can try it with the MX-60 as you are at only 142v. If it works better then a new higher voltage CC would be required for winter higher voc.

Let us know what you find out.

jay
Luke Christy

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