We use a Seaward Solar PV150 for module testing. It quickly tests a range of data points and, when used with the irradiance meter, give a pretty good indication that a module is performing well. http://www.seawardsolar.com/products/pv150-solar-installation-test-kit
On Mon, Oct 5, 2015 at 10:46 AM, Starlight Solar Power Systems < la...@starlightsolar.com> wrote: > Bill, > > In the shop I have two electronic loads that I use nearly every day with > batteries and PV modules. One is a programmable 150W, 360V that can be set > for constant power, current or voltage (like this: > http://www.amazon.com/Programmable-Electronic-Load-360VDC-CSI3710A/dp/B00D7QGSV4). > It’s small enough to take to the field. The other is a 2kW model that I use > for battery load and discharge testing. It’s too big to move. > > I also use the Daystar DS-05A (seen here: > http://www.amazon.com/Daystar-DS-05A-Solar-Digital-Meter/dp/B00YVTXZJ4/ref=sr_1_fkmr0_1?s=electronics&ie=UTF8&qid=1444055204&sr=8-1-fkmr0&keywords=Daystar+PV+irradiancePV) > irradiance meter to calculate power by holding it in the same plane as the > module to determine actual irradiance striking the surface. > > Another tool I use is a simple instant read, non contact infrared > thermometer to check the cell temperature under test. > > With these tools and a little information, I can measure instant power and > calculate module degradation. Others have suggested higher cost tools but > these low cost tools have been reliable for many years. > > Larry > > On Oct 4, 2015, at 7:56 PM, frenergy <frene...@psln.com> wrote: > > Wrenches, > > As time passeth, we're bumping more into older PVs/arrays that have > questionable outputs. After minimizing the variables (dust, temps, sun > angle, wiring, expected deterioration with age, etc) and still coming up > with low numbers. Testing individual PVs' Voc and Isc don't seem to tell > the whole story as they often look good. > > Would not a definitive test be to wire a suspect PV to an > inexpensive mppt CC (oxymoron?) and then to an orphaned battery. The > battery would have to have a mondo (surplus) rheostat paralleled to it to > maintain a steady voltage during the test. With appropriate metering in > place, you would then have Vmmp and Immp as the rheostat is tweaked to hold > a steady batt voltage and the CC finds the knee. > > Help me here. I know its a little spendy to cobble up but the value > of nailing an offender might be worth it. Am I missing something? Is it > common for inverters to fall off in output gradually? > > Bill > Feather River Solar Electric > > _______________________________________________ > > _______________________________________________ > 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 > > -- Chris Mason NABCEP Certified Solar PV Installer™ Solar Design Engineer Generac Generators Industrial technician www.cometsolar.com <http://www.cometenergysystems.com> 264.235.5670 869.662.5670 Skype: netconcepts
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