Photovoltaic solar cells are very much depends on the component of the overall system configuration and optimization of the system which consist by system components, batteries, controller and inverter; there are several basically relevant parameters must be obtained before design the system:

The design of the system, is an independent, network or Grid-on? 

Are the batteries necessary? How long does it takes to full charge of the batteries?

Is it DC or AC?

The demand of continuous raining days requirements?

The number of daily electricity consumption?

The sunshine duration?

Where to install the solar power generation systems?   

The load power of the system?

Judge carefully based on the above parameters, start the preliminary blueprint, then optimizes the design, and the design plan of the power system has a huge effect on the quality of solar power system.

There are few things must be clear before design:
the working power of the product ;
The demand of continuous raining days requirements ;
which is this system going to install and which area.