For the sake of example if you are getting 5 hours of direct sunlight per day in a sunny state like california you can calculate your solar panel output this way.
Average solar panel output per hour.
So if you have a 7 5 kw dc system working an average of 5 hours per day 365 days a year it ll result in 10 950 kwh in a year.
Based on the table we know that a 300 watt solar panel produces 36 5 kwh electricity per month.
That s approximately equal to the power of the sun at noon on a sunny day at the equator.
Putting it all together.
Therefore to figure out how much power the panel produces in a day simply multiply the 250 watts by 4 hours which comes to 1000 watts per day.
Each solar panel is also 200 watts per panel solar angle towards the sun is set in an ideal path south or south west this size solar panel system could produce 2kwh per hour of sunlight so this would make about 8 kwh for a 20 panel system after the energy loss.
If that panel received full sun for one hour you d get 250 watt hours of electricity.
5 hours x 290 watts an example wattage of a premium solar panel 1 450 watts hours or roughly 1 5 kilowatt hours kwh.
Note that these figures show average output.
If you know the average daily peak sun hours for your location you can calculate the kwh your solar panels will make on a daily monthly and yearly basis.
A peak sun hour is the equivalent of the sun shining at an intensity for 1 000 kw per square meter for one hour expressed as 1 kwh m.
To figure out how many kilowatt hours kwh your solar panel system puts out per year you need to multiply the size of your system in kw dc times the 8 derate factor times the number of hours of sun.
This map shows watt hours per 100 watts of solar panel system capacity.
A 300 watt solar panel will produce on average 1 2 kwh of electricity over a day and 36 5 kwh of electricity per month.
It also assumes a perfect installation facing due south at an optimal tilt angle and unshaded between 9am and 3pm.
In the picture above the label shows an stc rating of 250 watts for the panel.