HI Drake, Its unlikely that all of the wattage degradation of the module would be in volts only. In conversations I've had with experts, most numbers appear to be 1/2 volts and 1/2 amps.
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. thanks, jay peltz power On Apr 6, 2010, at 1:58 AM, Drake Chamberlin wrote: > 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 > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org >
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