[RE-wrenches] Voltage degradation

[Nick Soleil]

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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