There are two main tests that you can perform in order to test the wattage of your solar panel – the VOC or voltage open circuit test, and the ISC or current short circuit test. As with all types of technical tests, we actually recommend these are performed by licensed professionals such as our team here at Skyline Solar.
If you have a solar panel system installed on your home or business, you may want to test each solar panel for wattage occasionally. This can be one of a range of tests that helps ensure that your panels are working properly and at full capacity.
When solar panels are given a power rating, the number is based off a laboratory test, where the solar panel is exposed to an hour of simulated sunlight that measures 1,000 watts per square meter. During these tests, the solar panels are also kept at a constant temperature of 77 F, as temperature fluctuations can also impact performance.
Check the wattage and compare it to the panel’s max power, or Pmax. This is the panel’s listed wattage and can be found on the back of the panel. At this point in the day, the clouds had rolled in, so my watt meter measured an output of 24.4 watts from my 100 watt solar panel.
Simply use the amperage and voltage readings your earlier tests revealed and perform the following equation: Volts x Amps = watts. Once you have calculated the real wattage of your solar panels, you can multiply this number by the average hours of sunlight you get per day: Solar panel watts x average hours of sunlight = daily watt-hours
To accurately test a solar panel, set the multimeter to measure DC voltage and make sure proper lead connections to the positive and negative wires. When setting up your multimeter for testing solar panels, keep in mind the following basics: Select DC Voltage Mode: Set the multimeter to measure DC voltage to assess the output accurately.