This is totally dependent on your power use, roof size, and geographic location. However, for the ordinary family, a 6.66 kw system is sufficient to meet the majority of the energy usage. This will amount to about $450 every quarter.
Your solar system operates even on gloomy or rainy days. They may, however, produce significantly less electricity, as little as 10% or 25%. As a result, if you have a grid-connected system, your grid connection compensates for it.
A grid-connected solar power system is an electrical power station that employs direct current (dc) electricity from solar panels to produce power within an existing electrical grid's utility wires. Excess energy created by such systems may be sent back into the grid, which is especially useful in the case of renewable energy generation.
It is determined by your pattern of power consumption. If you use a lot of electricity in the evenings and at night, you should absolutely include a solar battery in your solar energy system. It may, however, need an increase in the size of your existing solar power system.