Solar Panel Stc Vs Ptc

Because the stc rating is a measurement calculated under ideal laboratory conditions it s not always a useful metric for designing your system.

Solar panel stc vs ptc.

Generally if no ptc value is listed in the specifications for a photovoltaic panel you can expect it to be about 10 to 15 percent less efficient than the stc rating. Every panel is assigned a nameplate power output value which is measured using stc standard test conditions. Ptc is an acronym for pv usa test conditions which were developed at the pv usa test site at the university of davis california. Stc in an acronym for factory standard test conditions which is 1 000 watts per square meter solar irradiance 1 5 air mass and a 25 degrees c.

Factors that affect solar panel efficiency. This is the most simple and easy to grasp way to quote because you just take the wattage of the panel and multiply it times the number of panels. The other way is ptc or performance test conditions. If you recall under stc conditions everything is at 77 f 25 c.

The jinko solar jkm260p 60 panel mentioned above is at the high end of the scale ptc stc 0 916. Stc standard test condtions and ptc pvusa test conditions are two methods of testing module performance. Although ptc ratings offer a realistic view of photovoltaic output they don t indicate exact energy production. The ptc of solar panels with stc rating of 260 watts varies in the gosolarcalifornia table from 217 1 watts ptc stc 0 835 to 239 8 watts ptc stc 0 922.

The primary difference between stc and ptc is temperature. Ptc power rating power ratings measure a solar panel s power output in watts. As far as i can tell the biggest difference between standard test conditions stc and pvusa test conditions ptc is that ptc tests are performed in air which is 5 degrees cooler and moving at 1 m s. To complicate matters there are multiple wattage ratings for every module stc ptc and noct.

Under ptc everything is heated up as if it were in the sun. Because solar direct products have min and max wattage ranges knowing what a solar panel will produce is critical. For instance a candaian solar cs3k 320ms has an stc rating nameplate value of 320w and a ptc rating of 298 1w. The solar cells within the panel are raised to their normal operating cell temperature which is typically around 113 f 45 c.