Selection of Solar Panels for 4kw

Here's just one of the myriad of places to start.

4kw is the total power required for your system.

multiply the power rating(W) of the load

by the time (h) the load will be in use to get the energy requirement (Wh).

add 20% of the energy requirement to compensate for power loss.

this s the total system energy requirement(E Wh).

the daily system requirement amp hour(Ah) C = E/V, where v is solar voltage.

daily charging current from your solar panel I = C/T, where T(h) is the time over which you expect to receive fairly bright sun shine.

a solar panel with charging current slightly >or = to I is the required one.

check on manufacturer's nameplate for the value of I.

that is from me.

cheers.