1. System rated voltage
That is, the rated voltage of the battery. The voltage of a single solar cell is generally 0.4~0.7V. The common solar cell modules are 36/54/60/72/96 in series, and the voltage is about 18/27/30/36/48 V.
2. LED lamp cap power
That is, the lamp cap power or the driving efficiency of the controller, which is determined according to the specific installation environment. The higher the lamp pole, the better the lighting effect, and the higher the lamp cap power naturally requires.
3. Battery capacity
The capacity of the battery is also the focus of attention. The capacity is too small to meet the lighting needs at night; If the capacity is too large, the battery will always be in a state of power loss, which will cause waste and affect the battery life.
The ratio of battery capacity (Ah) to load capacity (Ah) should be more than 3-6 times. If there are fewer consecutive rainy days in the installation area, more than 3-4 times is enough. If there are more consecutive rainy days, at least 5-6 times is enough.
4. Compensation in rainy days
This is determined according to the local climate conditions. The charging efficiency of the solar cell cover plate on rainy days is naturally lower than that on sunny days. Therefore, it is necessary to ensure that the battery can store enough power to enable the solar street lamp to operate normally on rainy days, which also involves the working efficiency of the battery panel.
5. Interval between consecutive rainy days
That is, the number of sunny days between two consecutive rainy days. It should be noted here that the average sunshine is generally used as the basis for supplementary charging in sunny days when calculating relevant parameters, and the actual radiation amount in sunny days is greater than the average sunshine.
In addition, the battery is not completely charged in rainy days, so when this parameter is used in calculation, it is not necessary to really select the interval between consecutive rainy days, and the value can be appropriately amplified. The ratio of the interval between rainy days and rainy days is 1:3 or 1:4.
6. Local sunshine radiation
This can be directly queried on the Internet. The best angle of monthly average radiation is selected. The minimum average value of three months is required. During installation, attention must also be paid to the installation angle and direction to ensure that the solar street lamp can receive sufficient sunlight and ensure the charging efficiency. According to the specific environment, the range of ± 20 ° in the south is a good position.
7. Output power of solar panel
The solar panel is generally composed of multiple solar cells in series. Its capacity depends on the total power consumed by lighting sources, line transmission components, and local solar radiation energy.
In general, the output power of the solar panel should be more than 3-5 times of the light source power, more than 3-4 times in areas with abundant light and short lighting time, and more than 4-5 times in areas with poor lighting conditions and long lighting time.
8. Daily load working time
Nowadays, solar street lamps are designed intelligently. They are usually bright at the beginning of the night when people are busy. At this time, most of them work at 100% full power. In the dead of night, the brightness will be smaller, and only 50% power may work. When calculating, the equivalent full power working time should be used.
9. Charging efficiency of controller assembly
There are generally two types of controller charging control modes: PWM and MPPT. The corresponding charging efficiency of these two types is different. PWM has three stages of charging modes: strong charging, balanced charging and floating charging, which can solve the problem of insufficient battery charging and short battery life. However, the charging efficiency is not as good as MPPT.
The charging stage of MPPT solar controller is divided into MPPT charging, constant voltage equalizing charging and constant voltage floating charging stages, which can enable the system to charge the battery at the maximum power all the time. Therefore, the charging efficiency is also very high, and the price is several times or even dozens of times of PWM. It should be based on your own needs, and the relevant parameters should be based on the specific components.
10. Driving efficiency of controller components
As a reference for calculating lamp cap power and setting lamp cap drive current.
11. Battery conversion efficiency
The corresponding efficiency of different batteries is different. Nowadays, solar street lamps are generally designed in an integrated way. The conversion efficiency of the supporting battery, lithium iron phosphate battery, is much higher than that of the lead-acid battery in the past, generally between 92% and 95%.
12. Comprehensive loss compensation coefficient
This generally takes into account some effects caused by line loss, dust, shadow shielding, battery coulomb efficiency, and temperature. When calculating relevant parameters, the values are generally between 1 and 1.4.
