by Sarah Latimer, Survival Blog:
(Continued from Part 1.)
Question: How is my system size being determined?
Question: How many hours per day of power production will I have?
Here is where a little ‘art’ comes into all this ‘science’. Panels come in a few different sizes, usually around 325 to 425 Watts. The most common seems to be 400 Watts of generation. What they try to do is balance your usage with the size of panels. In the above case, it would take about 50 panels @ 400 watts per panel to equal the 19kW system (actually 20, but that is where the ‘art’ comes in).