[RE-wrenches] Voltage degradation

[Darryl Thayer]

Drake, I measured and published a paper in 1992 on the after 10 year performance of solar modules, my study concluded these modules degraded approximately 1% per year. The purpose of the study was the effect on utility demand.
 
I have heard there are some very good studies with similar results.
 
Thank you--Darryl

--- On Fri, 4/9/10, Drake Chamberlin <drake.chamberlin at redwoodalliance.org> wrote:


From: Drake Chamberlin <drake.chamberlin at redwoodalliance.org>
Subject: Re: [RE-wrenches] Voltage degradation
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Date: Friday, April 9, 2010, 12:24 AM


What is the documentation for 10% module voltage degradation?  I have heard different ideas on what will degrade over how much time.  For direct grid tie, I shoot for a voltage drop 1% maximum on the DC side.

Thanks,

Drake 

At 11:08 AM 4/8/2010, you wrote:

I usually keep in mind that the modules will degrade by 10%  However, if you are one of those wrenches promoting 3% DC Voltage Drops, maybe you should add some more.
 
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037



From: Drake Chamberlin <drake.chamberlin at redwoodalliance.org>
To: re-wrenches at lists.re-wrenches.org
Sent: Tue, April 6, 2010 1:58:56 AM
Subject: [RE-wrenches] Voltage degradation

Esteemed Wrenches, 

How much voltage overhead should we have available on our arrays to allow for inverters not to fall out of their DC voltage operating range?  Since the module power degradation is 20% over the warranty period, I usually shoot for a module voltage that can drop 20% and still be within the MPPT range of the inverter under the average high temperatures, since most of the degradation is in voltage.

Am I being too conservative with this number?  It always pushes the number of modules to the top of what is allowable on the string for the extreme low.  

Thanks,

Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
NABCEP TM  Certified PV Installer 
Office - 740-448-7328
Mobile - 740-856-9648 

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Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
NABCEP TM  Certified PV Installer 
Office - 740-448-7328
Mobile - 740-856-9648 
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