PV Performance Tests the Home Power Crew Ever wonder exactly how much power a cold PV module makes? We have. We placed just about every make module widely available on our "Democracy Rack", out in the sun. Then we measured their electrical output, temperature, and solar insolation. Here is what we found. The Test Jig & Procedure See Home Power #23, page 20 for a complete rundown of our PV module test jig and procedure. Here's what we do in a nutshell. We wire the module into the jig using the instruments shown below. INSERT JIG Schematic This test jig allows us to take actual data from each module. With four Fluke 87 DMMs we measure the following data: module voltage, module current, module temperature, air temperature, and solar insolation. The DMM measuring voltage is connected directly to the module's terminals. The DMM measuring module current uses a shunt (10 Amperes, 10 milliVolt, 0.1% accuracy). A Fluke 80T-150U temperature probe is used to measure both module temperature and air temperature. A Li-Cor 200SB pyranometer measures insolation. This data was taken at Agate Flat, Oregon (42ø 01' 02" N. 122ø 23' 19" W.) at an altitude of 3,300 feet. The date of this test was 12 January 1993. All modules are mounted on the same 12 foot by 12 foot rack, i.e. they are in the same plane. This assures equal access to sunlight. All modules were measured with the same instruments in the same places. Ambient air temperature was 0.2øC. (32.3øF.) to 3.7øC (38.7øF.) with a slight breeze blowing. The ground was covered by two to three feet of snow. We froze our butts off getting this data. The Photovoltaic Players Most of these modules have had their performance measured by us during the summer of 1991. We reported on their hot weather performance in Home Power #24, page 26. What follows here is winter testing of the same six different brands of modules modules, with two new brands added. All modules are listed alphabetically. Carrizo ARCO 16-2000 This is a 9.5 year old ARCO 16-2000 module we purchased on the open market. It has 33 series connected, single crystal, round PV cells. We've had this module out in the sun for the last 1.5 years. Carrizo ARCO M52 QuadLam This module is a set of four ARCO M52 laminates wired in series to make a single QuadLam module. This 8.5 year old module was suppled for testing by Mike Elliston of Carizzo Solar. The resulting module of four laminates contains 48 series connected cells and a total cell count of 144 PV cells. The PV cells used to make these laminates are 3.75 inches square and are single crystal types. We've had this module out in the sun for the last 1.5 years. Kyocera K51 We tested a K51 Kyocera module that we purchased new on the open market. This module contains 36 series connected square multicrystal PV cells. We've had this module out in the sun for the last 1.5 years. Siemens M55 We tested a M55 Siemens module sent to us new by its maker. This is a current production, single-crystal, PV module. This module contains 36 series connected square PV cells. We've had this module out in the sun for the last 1.5 years. Solarex MSX60 We tested a 1.5 year old, MSX60 Solarex module that we purchased new on the open market. The performance data of this multicrystal module is printed on its back. This data is the result of flash-testing of this specific module, not a "generic" rating like almost every other module. After flash-testing, a computer prints a label with the data for that specific module. This module contains 36 series connected square PV cells. We've had this module out in the sun for the last 1.5 years. Solec S50 The Solec S50 is a single crystal silicon module using 36 series connected square cells. This module was purchased retail and has been out in the sun for six months. This is an older model module and was made six years ago. Sovonics R-100 This is an amorphous silicon module supplied by Nick Pietrangleo of Harding Energy Systems. We've had this module out in the sun for the last 3.5 years. Uni-Solar UPM 880 This is an model UPM-880 amorphous silicon module sent to us by United Solar. This module is brand new and has only seen sunshine for three weeks before this test. The Data We are content to let the data speak for itself. We used manufacturer's ratings at a 25øC. module temperature. In the comparison tables that follow, this maker's performance specification is listed in the column called "Rated Value". Our measured data is in the column labeled "Measured Value". The column called "Percent of Rated" compares our measured results with the maker's ratings. The solar insolation data from the Li-Cor Pyranometer is accurate. At Agate Flat we often have solar insolation as high as 112 milliWatts per square centimeter. Conclusions The module that have remained on the rack for the last eighteen months show no significant performance degradation. The performance of these modules is certainly greater than in the last summertime test. The cold temperature has increased the performance of all the repeat tests. Coming up this summer, another hot weather test of all the modules on Home Power's "Democracy Rack." Access Author: Richard Perez. Testers: Chris Greacen, Mark Newell, Therese Peffer, Richard Perez, and Amanda Potter, c/o Home Power, POB 520, Ashland, OR 97520 ù 916-475-3179