The following is an example of the calculation of 100W output power, 6 hours of use per day:
1. First of all, the number of watt-hours consumed per day should be calculated (including inverter losses):
If the conversion efficiency of the inverter is 90%, when the output power of 100W, then the actual need for the output power should be 100W/90%=111W; if used 5 hours a day, the power consumption is 111W*5 hours=555Wh.
2. Calculation of solar panels:
Calculated according to the effective sunshine time of 6 hours a day, and then taking into account the charging efficiency and the loss in the process of charging, the solar panels' output power should be 555Wh/6h/70%=130W. 70% of which is the charging power. 130W, of which 70% is the actual power used by the solar panel during the charging process.
3. Charge controller selection:
The maximum output current of a 130W solar panel is 7.7A, so a charge controller with a charge current of at least 8A should be selected.
4. Selection of battery:
If 12V battery is used, its discharge depth is 50%, then 555Wh/12V/50%=90Ah battery should be used; if 24V battery is selected, then the capacity of battery should be 555Wh/24V/50%=45Ah.
II. Estimation and testing of solar cells
The rated output power of solar cells is related to the conversion efficiency, generally speaking, the unit area of the battery module, the higher the conversion efficiency, the greater its output power. The current conversion efficiency of solar cells is generally between 14 ~ 17%, per square centimeter of the cell, its output power in the 14 ~ 16mW, per square meter of the solar module output power of about 120WP.
The test of the solar module, you need to use a special testing equipment, testing under standard conditions. Due to the testing equipment is very expensive, the general test method is: the use of tungsten iodine lamps or incandescent lamps, simulating sunlight, comparing the samples for comparison testing, the main test of its open-circuit voltage and short-circuit current, testing, pay attention to the control of the temperature, can not exceed 25 ℃.
Three, the basic formula
Power = voltage X current (W = UI) power consumption = power X time (Q = Wh)
Four, the country's light conditions and the average peak sunshine time
Table 1 is the different regions of the sun's light conditions.
Table 1
Regional Division
Rich Areas
More Abundant Areas
Available Areas
Deprived Areas
Total Annual Radiation
Kcal/m2year
≧140
120-140
100- 120
≦100
Annual sunshine hours
≥3000h
2400h~3000h
1600h~2400h
≤1600h
Region
Western Inner Mongolia
Western Gansu
Xinjiang South
Tibetan Plateau
Northern Xinjiang, Northeast China, Eastern Inner Mongolia, North China, Northern Shaanxi, Ningxia, Gansu, part of Gansu, Eastern Tibetan Plateau, Hainan, Taiwan
Northern Northeast China, Inner Mongolia, Lower Yangtze River, Fujian, Guangdong, Guangxi, Guizhou, part of Yunnan, Henan, Shaanxi
Chongqing, Sichuan, Guizhou, Jiangxi, part of Jiangxi
In order to have a better visualization of the local conditions, we need to have a better understanding of the local conditions.
In order to more intuitively understand the average distribution of solar radiation per day in each region, Table 2 gives the correspondence between the total annual radiation and the average daily peak sunshine hours (the equivalent time that a solar cell can receive 1000W/m2 irradiance per day).
Table 2
Total annual radiation
kcal/m2 per year
100
110
120
130
140
150
160
170
180
Average peak sunshine hours h
3.19
3.50
3.82
4.14
4.46
4.78
5.10
5.42
5.75
Through the above information, it can be seen that solar energy luminaire design is related to the geographic location of the luminaire's use. The relationship between the rated output power of the solar module and the input power of the lamps in East China is about 2~4:1, the specific ratio should be decided according to the daily working time of the lamps and the continuous cloudy day rain lighting requirements.