<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">HI Drake,<div><br></div><div>Its unlikely that all of the wattage degradation of the module would be in volts only.</div><div>In conversations I've had with experts, most numbers appear to be 1/2 volts and 1/2 amps.</div><div><br></div><div>But if you can get your modules to get a 20% over there is no draw back except a small % efficiency loss from the higher Vmp.</div><div><br></div><div>thanks,</div><div><br></div><div>jay</div><div><br></div><div>peltz power</div><div><br><div><div>On Apr 6, 2010, at 1:58 AM, Drake Chamberlin wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>
Esteemed Wrenches, <br><br>
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.<br><br>
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. <br><br>
Thanks,<br><br>
<x-sigsep><p>
<font color="#0000FF">Drake Chamberlin<br>
Athens Electric<br>
OH License 44810<br>
CO License 3773<br>
NABCEP </font><font size="1" color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
Office - 740-448-7328<br>
Mobile - 740-856-9648 </font></p></x-sigsep></div>
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