Geoff, Daryl, and others, To be clear, Sanyo's product is not an amorphous-silicon (a-Si) product. It has a-Si coatings that help with the electron flow at the surface of the cell. There is no reason to believe that the Staebler-Wronski effect, so well known over the past 30 years, has any impact on this product. It is not really a multi-junction cell.
The issue of sizing inverters to array size is a many-facetted issue. I conservative rule of thumb would be to size the array STC-rating to be equal to the ac KW rating of the inverter. As long as you are clear that the system will only very rarely ever reach full power, everything is fine. It is less of an art than a science in that programs, such as PVSYST, can predict quite accurately how much energy is lost if you undersize a PV inverter. The 125% array-to-inverter power number discussed below would only hold true for installations that are dominated by hot conditions, modules at minimum spec of -10% of nameplate rating, and no snow or altitude enhancements. Inverters are so much cheaper now that undersizing inverters makes very little sense. Bill. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Geoff Greenfield Sent: Wednesday, April 15, 2009 6:15 AM To: daryl solar Cc: RE-wrenches Subject: Re: [RE-wrenches] Sanyo Semi-facial My understanding of amorphous is that there is a 2-3 week burn in of higher performance, then it levels off. The rated watts reflect the levelized performance. Re overstacking an inverter: the sma report from their sizing tool is useful- balancing best value, long term performance and inverter reliability is an artform more than science. Adding modules that perform at spec when we are used to a larger derate makes it that much trickier. For a brighter energy future, Geoff Greenfield President Third Sun Solar & Wind Power Ltd. 340 West State Street, Unit 25 Athens, OH 45701 740.597.3111 Fax 740.597.1548 www.Third-Sun.com Clean Energy - Expertly Installed ----- Darryl Thayer <[email protected]> wrote: > > hi all > 1) I have a 97kW system that just hit 95kW peak, which surprised me. > 2) Overloading the inverter, I was told that slight over load is OK and that if you overload up to 25% you will not have any significant annual loss. If this is not correct please up date me. > DT > > _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] 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
