How are the specifications of solar panels calibrated? When we look at the parameters of the solar lamp, we also notice the specifications of the solar panel. In general, the specification table marks the voltage and power of the solar panel, and some specification tables mark the size of the solar panel. In fact, the power and size of solar panels are related. In general, the solar panel power we label is the maximum power that can be generated by solar panels when the solar radiation power reaches 1 kilowatt per square meter. The efficiency of the solar panels we use is about 18 to 21 percent. This means that we receive 1 kilowatt of sunlight to convert 180 watts to 210 watts of power. In general, the effective area of solar panels is about 85% of the total area of solar panels. So a square meter of solar panels, its power is about 130 to 160 watts. For example, SEKURO Integrated Solar Street light SKEA-L02-320, Fixture up size is 916*365mm, solar panel size is about 0.86*0.33m, we can calculate the solar panel wattage=0.86*0.33*140W≈40W. That is, once we only know the size of the solar panel, we can roughly figure out the power of the solar panel. If someone declare the big wattage by small size solar panel, you will know that they are cheating you. 

What means 1 kilowatt per square meter? It is roughly the average radiant power achieved by midday sunlight in mid-latitudes (such as Beijing). If we use the solar panel in the tropics, then at noon on a sunny day, the intensity of sunlight is greater than this value. In other words, it is possible to output 110W of power with 100W solar panels. Of course, due to the different efficiency and conditions in use, solar panels can generally only charge the battery at less than the nominal power. We will choose a good solar charging controller, which will greatly improve the efficiency of the solar panel. The output voltage of the solar panels used in small solar lamps is generally 5V or 6V, because we can charge 3.2V or 3.7V lithium batteries without increasing or decreasing the voltage.