A solar panel is rated by the amount of power it creates at Standard Test Conditions, or STC. It is provided in.
These conditions include the intensity of the sun: 1000W/m2, the angle of the light hitting the panel directly, the temperature at 25℃ or 77℉, and other criteria. So actual mileage may vary, based on all of these factors in the real world.
When a 12V solar panel is rated at 100W (like SUAOKI SOLAR ), that is an instantaneous rating, if all of the test conditions are met, when you measure the output, the voltage will be about 18.9 volts and the current will be 5.29 amps. Since watts equals volts times amps, 18.9 volts x 5.29 amps = 100 watts. To figure out how much power is generated over a period of time, you can to multiply the watts times the number of hours it is running. So in one hour, 100W x 1 hour = 100 watt hours.
To determine how much power the solar panel will generate in a day, we have to find out how many of sunlight per day, it is called “Peak sun hours”, you can find it easily in insolation world map.
You can see my previous picture (3 kW system), in July I can get 6.8 hours of sunlight, but in December only 2.7 sun hours. So in July, my 100W solar panel generated 100W x 6.8 = 680 Wh. I know, that’s figuring on losing about ⅓ of your power. I now end up with 453-watt hours of power that I have made with my 100W solar panel on a July day. Obviously, these numbers will vary depending on the location and the season.
What can I do with that power?
With 453 Wh of power I get from my 100 watt solar panel, I can use it for:
I can run my laptop that uses 45W for 10 hours.
I can power 5 of my 10W LED lights for 9 hours.
I can run my PC desktop that uses 75W for 6 hours.
I can run a Microwave oven for 15’.
I can run my LCD Tivi for 3 hours
I was very tired when tried to estimate what I can do with my 100 watt solar panel. But I know a tool that can help a lot to calculate electrical consumption by using appliance energy calculator by US Department of Energy