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

[Luke Christy]

Allen, 
With 8 modules in series I think I'll be looking at a Classic 250 for sure to be comfortable with winter morning VOC. 
I don't really know what kind of combiner situation I'll find up in the attic. It may be easy enough to re-wire into strings of 6 instead of strings of 8, though that is still probably going to push me just over the 150 VOC hard limit of the MX-60. I may not be able to get around replacing the controller. 

-Luke



On May 31, 2015, at 10:59 PM, Allan Sindelar <allan at sindelarsolar.com> wrote:

> Jay,
> Whoa, I'd be careful there. Unless there's been a change while I was away on my bicycle, Outbacks are still 140V rated maximum voltage and 150V hard maximum. 142Voc in May suggests that doubling strings in series will easily exceed max Voc in winter. That's why I previously suggested Classic 200 or 250. Am I missing something?
> Allan
> 
> Allan Sindelar
> allan at sindelarsolar.com
> NABCEP Certified PV Installation Professional
> NABCEP Certified Technical Sales Professional
> New Mexico EE98J Journeyman Electrician
> Founder (Retired), Positive Energy, Inc.
> 505 780-2738 cell
> 
>  
> On 5/31/2015 2:23 PM, jay peltz 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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