Wrenches, So MPPT,s working at high voltage high and high current with even with the electronic switching you will generate heat and over time heat kills Fun times
On Mon, Jan 27, 2025, 8:04 PM Jeff Clearwater via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > Ahh I see the light now on the inverter size point. Still I wonder if all > MPPts are made equal in terms if they ability to clip high ratios with no > ill-effects. > > Sent from my iPhone > > On Jan 27, 2025, at 7:55 PM, Jeff Clearwater <je...@villagepowerdesign.com> > wrote: > > Yes I’ve wondered about this too and there is much debate on forums etc > about exactly how this works. > > Large PV plants have long used 1.4 order of magnitude ratios to maximize > economics (but much of that was under “per watt” incentives rather than > performance based incentives). > > However I’ve long wondered what the true effect of red-lining MPPTs is. > I’ve seen it as more of a lifetime issue but I wonder that if you consider > overheating of the circuit if we might actually be clipping more than just > squaring the top off the curve. Perhaps PVWatts modeled this? They are > pretty thorough there at NREL. Or perhaps they have a bug or sloppy > programming. It would be worth asking them. Anyone got a buddy at NREL we > can ask? > > > > > > > > > > > Sent from my iPhone > > On Jan 27, 2025, at 12:43 PM, jay via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > > HI David, > > My point exactly. > > > > On Jan 27, 2025, at 1:35 PM, david quattro via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > > Jay you are right - that doesn’t make sense because with more PV, the > system will reach “max AC out“ power sooner every morning and hold it > longer into the evening > > > > > On Mon, Jan 27, 2025 at 12:20 PM George McClellan via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > >> Probably due to clipping. The panels are generating more energy than the >> power electronics can process, so that excess energy gets cut off (or >> clipped). It looks like a 1.2 ratio is optimal. >> >> George McClellan | Senior Manager, Technical Sales | REC Americas LLC >> 735 Tank Farm Rd Ste 130 | San Luis Obispo, CA |93401 >> <https://www.google.com/maps/search/735+Tank+Farm+Rd+Ste+130+%7C+San+Luis+Obispo,+CA+%7C93401?entry=gmail&source=g> >> Cell phone +1 805 704 3226 | Fax +1 805 357 6104 >> www.recgroup.com | george.mcclel...@recgroup.com >> >> >> >> >> -----Original Message----- >> From: RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> On Behalf >> Of jay via RE-wrenches >> Sent: Monday, January 27, 2025 11:56 AM >> To: RE-wrenches <re-wrenches@lists.re-wrenches.org> >> Cc: jay <jay.pe...@gmail.com> >> Subject: [RE-wrenches] PV watts question >> >> Caution: This is an external email and may be malicious. Please take care >> when clicking links or opening attachments. >> >> >> HI All >> >> I’m working with a customer who’s pretty savvy and is using PV watts for >> his design. >> >> What I can’t figure out is the kwh/year goes down if he uses dc/ac ration >> of 1.5 instead of 1.2 which is the default. >> >> Hes in Santa Fe NM. >> >> .8 ratio= 1663 kwh/yr >> 1.0 ratio = 1668 kwh/yr >> 1.2 ratio = 1671 kwh/yr >> 1.5 ratio = 1623 kwh/yr >> >> I was expecting that more PV = more kWh/yr. >> >> What am i missing? >> >> >> standard module >> fixed roof mount >> 14.08 loss’s >> 10 degree tilt >> 180 degrees >> >> >> >> jay >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> >> ________________________________ >> >> This message is private and confidential and may be privileged. Any >> unauthorized use, dissemination of the information or copying of this >> message is prohibited. If you have received this message in error, please >> notify us immediately and remove it from your system. Thank you. >> >> ________________________________ >> >> This message is private and confidential and may be privileged. Any >> unauthorized use, dissemination of the information or copying of this >> message is prohibited. If you have received this message in error, please >> notify us immediately and remove it from your system. Thank you. >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > > _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org