Solar power panels

[Rifrug]

I have read that you can take the 20KWH per day and divided by 6hours of sun shine = 3.3KW of panels. But solar losses is about 30% so you need to add 30% of panels to deal with losses that gives you 4.2KW of panels.
So 13 x 330W PV panels should do as it gives you 4290Watt. Than to choose a inverter that can handle the PV input of 4290W (I would think 5KW should do if your maximum load is not going to exceed the 5KW inverter). Now choose batteries that can take your load through the night without draining your batteries more than what the manufacturer recommend otherwise you will loose your warrantee. I use small cheap batteries that I replace every two years because I hammer my batteries during the night and they will only make about two years life, for me the warrantees are not worth the cost of paying about 4 times more for long life batteries. But that is your personal choice and affordability. (On your system I would think about 400AH x 48V might do, if you don't run geysers, stoves and pool pumps during the night. (Make 14 x panels as 13 is a odd number to connect strings, this is how I calculated my system and hope it guides you in the right direction)