18650 battery lithium ion 2200mah

　　Research on complementary control of solar energy and mains power driven by LED street lights

　　The photovoltaic complementary LED street lighting system is a street lighting system that mainly uses solar cells to generate electricity, supplemented by ordinary 220V AC supplementary power. Using this system, the photovoltaic battery pack and battery capacity can be designed to be smaller, basically when there is sunlight during the day. , use solar power to generate electricity that day and charge the battery at the same time. When it gets dark, the battery discharges and lights up the load LED. In most areas of our country, there are basically more than two-thirds of sunny weather throughout the year. In this way, the system uses solar energy to illuminate street lights for more than two-thirds of the year, and uses mains electricity to replenish energy for the remaining time. It reduces the one-time investment of solar photovoltaic lighting system and has significant energy saving and emission reduction effects. It is an effective method to promote and popularize solar LED street lighting at the current stage.

　　1 Photoelectric complementary LED lighting system design

　　1.1LED lighting load

　　Assume that the height of the photoelectric complementary LED street light pole is 10m and the light flux is about 25lm. 1W, 3.3V, 350mA LED lights are used to form two street lights. Each channel has 14 series and 2 parallel for a total of 28W, and the two channels are 56W. Assume that the street lights are illuminated for an average of 10 hours a day. The LED street lights are fully illuminated for the first 5 hours and the brightness is halved for the next 5 hours, that is, the battery consumption is reduced by half.

　　The actual drive current required is:

　　350mA×2×2=1.4A

　　Calculated based on 10 hours per day, the number of ampere hours required for the load is:

　　1.4A×5h+1.4A×0.5×5h=10.5Ah

　　The voltage is:

　　3.3V×14=46.2V

　　1.2 Battery pack capacity design

　　1.2.1 Selection of batteries

　　Since batteries for solar street lights are frequently in charge and discharge cycles, and overcharge or deep discharge often occur, battery performance and cycle life have become the most concerning issues. Valve-regulated sealed lead-acid batteries have the advantages of requiring no maintenance, not emitting hydrogen and acid mist into the air, good safety, and low price, so they are widely used. Battery overcharge, over-discharge and battery ambient temperature are all important factors that affect battery life, so protection measures should be taken in the controller.

　　1.2.2 Calculation of battery pack capacity

　　In the photoelectric complementary street light system, LED street lights are powered by complementary solar energy and mains power. Since sunlight changes greatly with the weather, when the sunlight is strong during the day, the solar panel charges the battery; at night, the battery supplies power to the load. On cloudy days, the load power is obtained from the battery. When the battery discharge voltage drops to the minimum allowable limit, it is automatically switched to the mains supply. The capacity of the battery is very important to ensure reliable power supply. If the battery capacity is too large, the cost and price will increase. If the battery capacity is too small, solar energy cannot be fully utilized to achieve energy saving.

　　Battery capacity Bc calculation formula:

　　Bc=A×QL×NL×T0/CCAh (1)

　　In formula (1), A is the safety factor, which is between 1.1 and 1.4. This formula is A=1.2; QL is the average daily power consumption of the load, which is the operating current multiplied by the daily operating hours, QL=10.5Ah; NL is the maximum power consumption. The number of long continuous rainy days, due to the use of photoelectric complementarity, can be taken as NL=1 day; T0 is the temperature correction coefficient, which is generally 1.1 above 0℃ and 1.2 below -10℃. This formula takes T0=1.1; CC is the battery discharge The depth is generally taken as 0.75 for lead-acid batteries and 0.8 for alkaline nickel-cadmium batteries. In this formula, CC=0.75.

　　Therefore, Bc=A×QL×NL×T0/CC=1.2×10.5×1×1.1/0.75=18.5Ah. In the actual design, we choose 48V, 40Ah maintenance-free valve-regulated sealed lead-acid batteries.

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