How much electricity can a solar panel produce in a day? This depends on the STC or PTC level of the panel; STC stands for standard test conditions and represents the power generated by the panel under ideal conditions. Manufacturers test the panels under conditions called solar peaks, which typically last about 4 hours when the sun is brightest. The peak value of the sun is calculated as 1,000 watts of sunlight per square meter of panel surface. The STC rating is the degree to which peak sunlight is converted into energy.
A panel with an STC rating of 175 watts converts one hour of sunlight to 175 watts. Multiply the STC rating of each panel by the number of panels and you will know how much energy the array generates at peak conditions. You then multiply that number by the number of peak hours of sunshine obtained by the panel each day and you will know how much energy the solar panel system generates.
If each panel has an STC rating of 175 and you have 4 panels, then 175 x 4 = 700 watts. Therefore, 700 x 4 = 2800 watts are generated during peak sunlight. Please note that the solar cell array also generates electricity in low light, so the total energy generated during the day in this example will be higher than 2800 watts.
