What Is a Smart Charger?

Smart charger is a universal smart charger. Different charging modes and corresponding algorithms can be given for the characteristics of each battery to achieve the best charging effect. When designing a universal smart charger. The charging characteristics of the three types of batteries need to be fully considered, and different charging modes and corresponding algorithms are given for the characteristics of each type of battery. Rechargeable batteries have high performance-price ratio, large discharge current, and long life. They are widely used in various communication equipment, instruments, and electrical measuring devices.

Smart charger

Smart charger is a universal smart charger. Different charging modes and corresponding algorithms can be given for the characteristics of each battery to achieve the best charging effect. Designing Universal Intelligence

can

Ordinary batteries : The plates of ordinary batteries are composed of lead and lead oxides, and the electrolyte is an aqueous solution of sulfuric acid. Its main advantage is that the voltage is stable; the disadvantage is that the specific energy is low (i.e. per kilogram)

To ensure the normal life of the battery, it is necessary to provide the battery with an acceptable and scientific charging current. Intelligent chargers have been developed in this context. Whether a smart charger has reached the design target can theoretically be tested with a real secondary battery, but this method is a lengthy and difficult to operate process, which is not in line with actual conditions in research and production. Constant voltage electronic load can solve this problem well.

Principle of constant voltage electronic load

The electronic load is a power test instrument that uses high-power semiconductor devices to absorb the current provided by the power supply and convert it into thermal energy, thereby reaching an analog load. The working principle of the constant voltage (CV) electronic load is shown in Figure 1. It will absorb enough current from the power supply to control its output voltage to reach the set value, so it can simulate the terminal voltage of the battery, and can quickly and accurately test the output characteristics of the smart battery charger. Current-limiting characteristics.

(a) Principle of electronic load (CV) (b) Output characteristics

Figure 1 Principle and output characteristics of electronic load

Development of constant voltage electronic load

The schematic diagram of the JTU-100 electronic load is shown in Figure 2. It can absorb a maximum current of 10A. In the figure, V1 and V2 are adjusting tubes, Uref is an adjustable reference source, and 1, 2 are output terminals. No matter how the load changes, the set voltage can be obtained at terminals 1 and 2.

Figure 2 Schematic diagram of JTU-100 electronic load

Research on Performance Test of Smart Battery Charger

Figure 3 is a schematic block diagram of a smart battery charger developed to meet the charging requirements of a 12VVRLA battery under cyclic use conditions. The design indicators are:

The functional block diagram of Fig. 3 intelligent battery charger

(1) When Ub14.2V, constant current charging, the charging current is 2A.

(2) When Ub> 14.2V, the charging current decreases linearly with the increase of battery voltage.

(3) When Ub 15.5, charge the battery with a current of about 10mA to compensate the battery's self-discharge current.

(4) Charging threshold voltage temperature compensation coefficient is -23mV / (12VVRLA battery)

The test steps are as follows:

Connect power to JTU-100 electronic load and adjust the output to 13.5V.

Wiring according to Figure 4.

Turn on the switch of the electronic load first, and then turn on the switch of the smart battery charger. The ammeter displays 2A and the voltmeter displays 13.5V.

Gradually increase the output voltage of the electronic load. When the voltage is greater than 14.2V, the output current gradually decreases. When the output voltage of the electronic load rises to 15.5V, the current drops to about 10mA.

Gradually decrease the output voltage of the electronic load, and the reading of the ammeter increases linearly. When the output voltage is less than 14.2V, the reading of the ammeter increases to 2A and remains unchanged.

In order to measure whether the temperature compensation of the charging threshold voltage reaches the design target, the temperature sensor of the smart battery charger is placed in a thermostat and the charging curve at this temperature is measured. The measurement results are shown in Figure 5.