Was the inverter connected at the time of testing? If so I suspect the inverter is loading the solar array below Vmp
On Wed, May 17, 2023 at 11:23 PM frenergy via RE-wrenches < re-wrenches@lists.re-wrenches.org> wrote: > Wrenches, > > I've got a call from a customer that said their (my > install) 17 year old GT system went dead. Basic stats: 23, Mitsubishi > PVMF120EC3, label says V mpp= 17.6V and Voc = 22 V; top-of-pole; SMA > SB3800U. Its one string of 23 PVs. Full sun, 75 degrees ambient during > testing. When I checked DC voltage at the inverter landings I got ~23-29 > volts (fluctuating) same at the input side of the DC switch. These > panels have the old gasketted 4-screw covered J-boxes and screw > terminals inside, I removed the covers from three panels and got 9.5 > volts at the each of the panels' screw terminals, all the wiring > outside the boxes checks out. > > The system had been functioning normally 3 weeks prior. I > could check voltage at more panels I guess. Ideas? > > Bill > > Feather River Solar Electric > Bill Battagin, Owner > 4291 Nelson St.(shipping) > 5575 Genesee Rd. (USPS, UPS) > Taylorsville, CA 95983 > 530.284.1925 Office/ 530.258.1641 Cell > CA Lic 874049 > Solar powered since 1982 > > > -- > This email has been checked for viruses by Avast antivirus software. > www.avast.com > _______________________________________________ > 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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