Did you notice that in my calculation I divided the total amperage by 2 to get the average ampacity across the string. This seems to be the best way to deal with that. Otherwise the loss would have been over 2.8%
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: "ma...@berkeleysolar.com" <ma...@berkeleysolar.com> To: RE-wrenches <re-wrenches@lists.re-wrenches.org> Sent: Fri, June 11, 2010 7:02:00 AM Subject: Re: [RE-wrenches] AC wiring loss on micro-inverters Nick, Good to see other wrenches looking at this issue. However, remember that in the interconnect cable between the last and the second to last Enphase, the current is small. If you really want to see how the loss is adding up you need a more detailed analysis that averages the voltage drop for the entire system of interconnect cables. Mark Frye Berkeley solar Electric Systems > Hello wrenches and Marv: > How many Enphase inverters do you put on a single parallel string? > The Enphase manual allows for up to 15, but I have found that a single > string of 15 can have very high voltage rise on the AC wiring. Up to > 1.5% loss just on the Enphase cables, and that does not take into > account resistance at the plug connectors or any home-run wiring. > 15 inverters x 190 watts = 2850 watts > 2850 watts / 240 Volts = 11.875 Amps (however at the beginning of the > string it is 0 Amps) > Average Amps on the Enphase cables is 11.875 / 2 = 5.9375 Amps > length of contacts + internal wiring = ~6' > Total Enphase cabling length (6' x 15 inverters) = ~90' > 5.9375 Amps @ 240 V running 90' on #14 AWG CU = 1.4% loss > It is pretty hard to design for 1.5% voltage drop if you have to size for > 0% loss on your wiring! I hope Enphase will increase the size of the wire > in their cables soon. Have you experienced issues with micro-inverters > shutting off due to high AC voltages? > > 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: i2p <i...@aol.com> > To: RE-wrenches <re-wrenches@lists.re-wrenches.org> > Sent: Thu, June 10, 2010 4:50:47 PM > Subject: Re: [RE-wrenches] Real world PV production > > > > On Jun 10, 2010, at 7:57:53 AM, "Kelly Keilwitz, Whidbey Sun & Wind" > <ke...@whidbeysunwind.com> wrote: > > PV Watts VASTLY underestimate PV production >> in our area. > PV Watts underestimates in Central Ca too. > > Don > > > _______________________________________________ > 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 > > _______________________________________________ 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
_______________________________________________ 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
