Charge and discharge control and temperature compensation of battery for solar street lamp

　　 Because the input energy of the solar power generation system is extremely unstable, the charge and discharge control of the battery in the solar power generation system is more complicated than the charge and discharge control of the ordinary battery. The success of the design of the charge and discharge control circuit of Changhui solar street light will determine the success of the product. A complete and correct control circuit should have the functions of preventing reverse charging, preventing battery overcharge/discharge, and temperature compensation of lead-acid batteries.　　For solar street lights, if you use Ni-Cd batteries, you don’t need to prevent battery over-discharge. If the power of solar panels is relatively small compared to the battery, you don’t need to consider over-charging. This is the reason why many solar street lights currently use Ni-Cd batteries. But if you use other batteries, you must consider the above functions. 1. Anti-reverse charging function. Generally speaking, a diode is connected in series in the solar cell circuit to prevent reverse charging; 　　 2. Overcharging prevention function can be connected in series or parallel with a bleeder transistor in the input circuit, and the voltage discrimination circuit controls the transistor. The switch discharges the excess solar battery energy through the transistor to ensure that there is no too high voltage to charge the battery; 　　 3. Except for Ni-Cd batteries, other batteries generally need to have the function of preventing battery over-discharge, because over-discharge of the battery will cause Cause permanent damage. It should be noted that solar panels generally discharge at a small rate relative to the battery, so the discharge cut-off voltage should not be too low; 　　4, temperature compensation, the battery voltage control point described above changes with the ambient temperature, so solar The street lamp lighting system should have a temperature-controlled reference voltage to extend the service life of the equipment.