Jay, I don't really remember, it was years ago that I had that setup, and did not have any way to keep records except on paper which I did not do.
Brad On Wed, Oct 25, 2023 at 6:07 PM Jay via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > Hi Brad > > Out of curiosity, what is the actual difference between the two on those > cloudy days. > > Thx > Jay > > > > On Oct 25, 2023, at 5:04 PM, Bradley Bassett via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > > > I used to have both an array at a 60° tilt and one at 14° tilt. In the > winter the high tilt array did better on sunny days, and on cloudy days the > shallow array did better. They were different modules and different sized > arrays, so without more analysis than I did, it would be hard to tell which > is better through the winter, but it looked like they were similar in > overall output. However, once March rolled around the steeper array started > to do much better (more sun), and by summer the shallow array did much > better. I'm at 47° N and I think if I had a choice of any tilt, but without > adjustability, I'd probably set it at latitude or therabouts. If you're > west of the mountains you're probably going to need another source of power > anyway. I say that, but judging from the modelling I did of the output of > my micro-inverter system it might just be possible to get through the > winter with an array 500% overisized. And that with only 2 or 3 days of > battery autonomy. This was surprising to me. Do keep in mind that an array > with snow on it has 0 output. > > Brad Bassett > > On Wed, Oct 25, 2023 at 3:47 PM Kirk Bailey via RE-wrenches < > re-wrenches@lists.re-wrenches.org> wrote: > >> Hi All! >> >> >> We don't do a lot of pure off-grid systems and I recently ran across >> something I wanted to run by folks with more experience in this area: >> Optimal array tilt for our very cloudy PNW winters! >> >> My understanding has always been that latitude plus 10-15 degrees was the >> best tilt to address our winter energy shortage. However a paper I recently >> read (1), makes a compelling case for a much shallower tilt in situations >> where the cloud cover is so heavy that "diffuse" solar radiation is all >> that makes it through. They indicate that under those conditions a >> horizontal array will produce significantly more energy than even a >> two-axis tracker! >> >> Given that the challenge in our off-grid setups always seems to be making >> it through the really cloudy stretches, and that there is usually enough >> energy the rest of the time, should we be installing off-grid arrays at a >> shallower angle? >> >> Anyone tried this? >> >> >> Kirk Bailey >> >> k...@abundantsolar.com >> >> www.abundantsolar.com >> >> >> (1) Kelly, N.A., Gibson, T.L, 2011, Increasing the solar photovoltaic >> energy capture on sunny and cloudy days. Solar Energy 85, 111-125. >> >> >> _______________________________________________ >> 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 > >
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