Generally, the battery’s instruction manual will clearly label the amount of current the battery draws, but if this value is not available you will need to measure it yourself. Here are some points to measure the current.

1. Tools to be used

Digital multimeter: it can help you to measure the current value of the car battery and can read out the data directly.

Protective gloves and goggles: the electrolyte of the car battery may be acidic; goggles and protective glasses can make you avoid these hazards.

Electrode cleaner: the two poles of the battery may have dirt, which affects the current measurement.

2. Necessary Measures

Park the car in a safe and well-ventilated place to avoid the toxic gases emitted from the electrolyte of some batteries that may pose a threat to your health; turn off all electronic devices in the car to avoid affecting the results; bring good goggles and protective gloves to avoid contact with hazardous substances; use electrode cleaner to clean off the electrodes to avoid affecting the measurement results.

3. Measurement process

Insert the black pen into the “COM” jack, the voltage of the 12V car battery is more than 10A, insert the red pen into the “10V” jack; adjust the selector knob of the multimeter to the DC amperage level, which is usually marked as “A-“, and then according to the size of the current to choose the appropriate gear; and then the red wire to the positive terminal of the battery, the black wire to the negative terminal of the battery; read out the multimeter display, which is the size of the current of the car battery.

4. Precautions

Don’t connect the positive and negative poles of the digital multimeter in reverse, because it is likely to hurt the multimeter and battery.

You can’t dial the selection knob arbitrarily in the process of using, so as not to damage the digital multimeter, if you want to change the gear measurement, you need to disconnect the meter pen first, and then change the gear measurement.

Do not touch the metal part of the meter pen during the measurement process, so as not to affect the accuracy of the measurement as well as to cause harm to the human body.

Remove the battery when it is not used for a long time, so as not to corrode the multimeter.