Principle and circuit diagram of battery internal resistance tester

Measurement calibration method of battery internal resistance tester:

1. Press the [Power] switch to turn on the battery tester.

illustrate:

After turning on the tester, the LCD backlight can be turned on/off as needed.

Metrological calibration is used to calibrate instruments. Before measurement, select a standard battery, that is, select a battery and measure its voltage value as the standard voltage.

2. Press number key 4 to select [4. System Management].

3. Enter the password: 88888888.

4. Press number key 2 to select [2.Measurement calibration].

5. Short-circuit the clamp and press the confirmation button to perform self-calibration.

6. Self-calibration takes about 3 minutes. After the numbers on the screen are stable, press the confirm button.

7. Input standard voltage.

8. Connect the standard power supply (battery) with a clamp and measure the voltage.

Battery internal resistance tester circuit diagram

Measuring range: 0 – 500mΩ (10mA 1KHz)

The PCB uses an M8 electronic load to attach some circuits. Later integrated with M8 electronic load.

Principle: The M8 generates a 1KHz square wave, and the amplifier generates a 10mA 1KHz alternating constant current output source. After testing the resistance, the alternating voltage signal is amplified 250 times, and then the value is detected by the fast synchronous phase shift ADC of the M8.

The two capacitors C2 and C3 can be replaced with a 47uF/50V non-polar capacitor. The withstand voltage is 50V for measuring the internal resistance of high-voltage batteries.