Drake, At what temperature did you get that reading? If it was very hot, then that could just be poor temperature characteristics of the module. I have run into some modules, specifically Suniva's, that just do very poorly in warm temperatures. Otherwise, if the voltage is approximately 2/3 of what you would expect, then it is usually an issue in the module jbox. Either a bad diode or failed solder connection. This case is odd, because it is a little bit more than 2/3 the voltage. So maybe it was very cold with 1/3 the module not working, or very hot. Also, taking a look with an IR camera when the system is functioning can often show if 1/3 the module is not working or if there are some bad cells in the module.
Cheers, Dave *Dave Tedeyan, PE* Senior Engineer | Taitem Engineering, PC 110 South Albany Street | Ithaca, NY 14850 o. *607.277.1118 x121* f. 607.277.2119 www.taitem.com Solar • Sustainability • Energy • Design B-Corporation Best for the World 2018 Honoree On Tue, Jun 11, 2019 at 7:05 PM Drake <drake.chamber...@redwoodalliance.org> wrote: > Hello Wrenches, > > Would you expect a low open circuit voltage in a module to be due to a > problem in the J-box / diodes or the module itself? The OC voltage read > about 28.3 V, where as the STC OC voltage of the module is 37.3. > > The module is an LDK 240, which means no warranty. > > Thanks, > > Drake > > Drake Chamberlin > > > > > > *Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified > Solar PV 740-448-7328 *http://athens-electric.com/ > > _______________________________________________ > List sponsored by Redwood Alliance > > 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 > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/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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