Calculation of solar cell capacity
The basic data required for solar cell capacity calculation are:
(1) Determine all the load power and continuous working time, the rated working voltage of the load and whether there are special requirements.
(2) Determine the geographic location of the solar cell module installation: longitude, latitude and altitude.
(3) Meteorological data to determine the installation site: annual (or monthly) total solar radiation or annual (or monthly) average sunshine hours; the annual average temperature and extreme temperature; the longest continuous cloudy and rainy days; the maximum wind speed and hail and other special climate data.
Solar cell module peak power calculation
In the design of solar LED lighting system, the total power of the solar cell array should be determined according to the solar radiation parameters of the solar cell installation site and the characteristics of the load; the number of series and parallel components of the solar cell array should be determined according to the voltage and current requirements of the designed system.
The principle of solar module design is to meet the daily electricity demand of the load under average climatic conditions. Because the weather conditions are lower and higher than the average, it is necessary to ensure that the solar cell module and the battery work in harmony when the weather conditions are different from the average; the battery’s state of charge (SOC) will be significantly reduced in harsh weather conditions. Do not consider fully charging the battery as quickly as possible in the design of the output power of the solar cell module.(Knowledge reading of solar cell power.) If so, it would result in a large solar module, making the system cost prohibitive. In most of the time of the year, the power generation of the solar cell module will be far greater than the usage of the load, resulting in unnecessary waste of the solar cell module. The main role of the battery is to power the load when the solar radiation is below average. In the event that the solar radiation is higher than the average value subsequently, the solar cell module outputs more power than the load demanded, which will automatically charge the battery.
To design a solar cell module to meet the needs of the worst season of light, when designing a solar cell module, the first thing to consider is that the designed solar cell module output power should be equal to the average annual load demand power. In this case, the solar modules will provide all the energy required by the load. But this also means that the battery is in a state of power loss nearly half of the time each year. If the battery is in a power-deficient state for a long time, the plates of the battery will be sulfated. In the solar LED lighting system, there is no backup power supply to recharge the battery in poor weather, so the service life and performance of the battery will be greatly affected, and the operating cost of the entire system will also be greatly increased.
In the design of solar cell modules, a better method is to make the solar cell modules meet the load requirements in the worst light season, that is, to ensure that the battery can be fully charged even in the worst light conditions. In this way, the battery can be fully charged throughout the year, which can prolong the service life of the battery and reduce maintenance costs. If in the worst season of the year, the illuminance is much lower than average. In this case, the solar cell module is still designed according to the worst case, then the power output of the designed solar cell module will exceed the actual requirement at other times of the year, and the system cost will be increased. Therefore, the key to designing a solar LED lighting system is to choose the most cost-effective solution.