description:
Electric vehicles, electric tricycles, golf carts, etc. all use large-capacity lead-acid battery packs as power. High-power chargers can quickly and safely charge large-capacity battery packs. The charger uses the principle of constant current and constant voltage. The battery is safely and quickly charged. At the beginning of charging, the battery voltage is low, and the charger performs constant current fast charging. The charging current can be set according to the specific capacity of the battery. The machine can output current below 20A, with charging. Over time, the voltage of the battery gradually rises and the capacity gradually fills. When the battery voltage reaches the predetermined terminal voltage, the charger enters a constant voltage and a small current charge, so that the capacity of the battery is further filled, and the voltage comparator output indication inside the charger The signal, the green LED is lit. After charging for a period of time, the charging process can be finished. The machine can quickly and fully charge the battery below 48 volts, the charging power can reach 600 watts, and the volume of the charger is 200x180x65 mm. It weighs about 1 kg.
Introduction to working principle:
Fully automatic constant current limited voltage high power battery charger circuit diagram
STK702-015 is a powerful large-scale thick film switching power supply circuit, including auxiliary power supply, PWM control, output drive circuit, power FET output circuit and so on. It combines a simple and dedicated peripheral circuit to form a reliable switching regulator circuit. After the AC power is passed through the power filter, it is divided into two paths: one is rectified and filtered, and then supplied to the 31st and 32nd pins of the PWM pulse width control drive module STK702-015. The internal PWM starts to work, generating a 70KHZ switching signal and driving the power FET to be strong. After class D amplification, it is output by 25 and 26 feet. After the special LC circuit pushes the high-frequency transformer to work, after the secondary step-down, the fast recovery diode MOR3040PT is half-wave rectified and output. There is no filter capacitor, and this is the ordinary switch. There are some differences in power supply. Theory and practice tell us that pulsating DC has better charging effect on the battery than smooth DC, and the charging pulse frequency of this machine is as high as 70KHZ, so the charging effect is better and the charging speed is faster. The other circuit of 300 VDC is supplied to the auxiliary switching power supply, and the DC voltage of the auxiliary power supply is supplied to the PWM pulse width control driving module to provide a DC working voltage through a switching circuit.
When charging starts, the battery voltage is lower, the voltage difference from the charger is larger, and the initial charging current is large. If it is not limited, the battery and the charger may be damaged, so an ampler and an ampler in the unit are used. The current sampling resistor forms an automatic current limiting circuit. When the charging current exceeds the set value (for example, 10 amps), the voltage drop across the current sampling resistor causes an operational amplifier of the LM358 to output a low level, and the PWM pulse width control driving module STK702 is controlled. The pulse width of the -015 output is narrowed, so that the output voltage is lowered and the charging current is reduced. When the battery is fully charged (the battery voltage is generally 1.3 times the nominal voltage), the voltage comparator of another operational amplifier of the LM358 outputs a low level. At this time, the green LED is lit and the PWM pulse width control drive is turned off. The DC operating voltage of the module. It indicates that the charging is completed. At this time, the charger is only powered by the auxiliary power supply, and the power consumption is small.
Precautions for use:
1. Before charging, check for no-load. After turning on the 220-volt AC power supply, the red and green LEDs on the charger are lit. Use a multimeter to measure the no-load output voltage. The voltage should be 1.2~ of the voltage of the battery to be charged. 1.3 times or so.
2. The positive pole of the charger output is connected to the positive pole of the battery, and the negative pole is connected to the negative pole of the battery.
3. When charging, after the battery is connected to the charger, the red LED is still lit, and the green LED is off. When the battery is full, the red and green LEDs are lit, indicating that the battery charging has been completed, then the charger can be turned off. Power, remove the battery.
4. The charger should be protected from heat dissipation in a well ventilated area.
Physical map
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Zhoushan Chenguang Electric Appliance Co., Ltd. , https://www.vacuum-cleaner-motors.com