We find it can be very difficult (time consuming) to explain this to some customers. So we try to keep possibility of clipping to a minimum, maybe with obvious clipping occurring a few days a year. If module tilt or orientation is less than ideal, clipping is more rare and we might be more aggressive on the DC/AC ratio. This approach is not driven so much by the science but by the desire to avoid never-ending discussions with certain customer types.
--Charlie Pickard TruNorth Solar > On October 4, 2016 at 7:30 AM Will White <[email protected]> wrote: > > Mike, > > Have you read the Enphase white paper on module to inverter size? It > goes into good detail on why they do it. > > > http://www2.enphase.com/global/files/Enphase_White_Paper_Module_Rightsizing.pdf > > Thanks, > Will > > > -- > Will White > Curriculum Developer > > e: [email protected] mailto:[email protected] > w: http://www.solarenergy.org/ > p: 802-272-3092 > > PV Installation Professional > # 093006-34 > > On Mon, Oct 3, 2016 at 10:20 PM, Mike Kocsmiersky <[email protected] > mailto:[email protected] > wrote: > > > > > > Recently I’ve been concerned about power clipping of micro > > inverters and the design ratio of PV STC array size to inverter. If I have > > a 300W module going into a 250W micro inverter, there will be times when > > the potential power output is clipped because the micro inverter can’t > > handle all the power. I’m thinking cold day with 1000W/m2 irradiance. It > > is typical nowadays to have an STC array size to inverter ratio of 1.2. > > Have you seen any analysis on how much energy is clipped, vs how much > > energy output is increased by operating at a better efficiency spot on the > > micro inverter? This assumes that the micro inverter performs better when > > more fully loaded. > > > > Additionally over time the crystalline silicon module will degrade > > slightly as well, reducing the amount of power clipping. > > > > > > > > I welcome your thoughts. > > > > > > > > > > > > Mike Kocsmiersky > > > > Principal > > > > Phone: 413 883-3144 > > > > Spirit Solarhttp://www.SpiritSolar.net > > > > > > > > > > > > > > _______________________________________________ > > List sponsored by Redwood Alliance > > > > List Address: [email protected] > > mailto:[email protected] > > > > Change listserver email address & settings: > > > > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > > > List-Archive: > > http://www.mail-archive.com/[email protected]/maillist.html > > http://www.mail-archive.com/[email protected]/maillist.html > > > > List rules & etiquette: > > www.re-wrenches.org/etiquette.htm > > http://www.re-wrenches.org/etiquette.htm > > > > Check out or update participant bios: > > http://www.members.re-wrenches.org > > > > > > > > > > > > > > -- > Will White > Curriculum Developer > > e: [email protected] mailto:[email protected] > w: http://www.solarenergy.org/ > p: 802-272-3092 > > PV Installation Professional > # 093006-34 > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: [email protected] > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/[email protected]/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > >
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