The exact method for calculating how many solar panels you need depends on what power application you want to use your solar panels for. Here's a basic calculation:

1. Determine the target power requirements: First determine the total power you want your solar system to provide, usually in kilowatts (kW). This can be determined by looking at the equipment you expect to use solar power, the amount of electricity used and its power.

2. Consider daylight hours and efficiency losses: Consider the average daylight hours in your area and the efficiency losses of your solar panels. Usually, the rated power of solar panels is measured under standard test conditions, and there may be a certain loss of efficiency during actual operation.

3. Consider the intensity of sunlight: the intensity of sunlight in different regions may be different, which will also affect the power generation capacity of solar panels. You can find the average sunshine data for your area and take it into account.

4. Perform calculations: Based on the above information, the following calculations can be performed:

Total power required by solar panels (kW) = target power demand (kW)/(average sunshine duration (hours/day) * Solar panel efficiency * Sunshine intensity correction factor)

Note: The sunshine intensity correction factor is based on the specifications and performance of the selected solar panels and the sunshine conditions in the area.

Through the above calculation, you can know the approximate total solar panel power required. Keep in mind that this is only a rough estimate, and the actual installation needs to consider more factors such as array layout, shadow occlusion, system reliability and scalability. When making specific solar system designs, it is best to consult a professional solar system installer or engineer.