Method for measuring the capacity of lithium batteries using a multimeter
Strictly speaking, a multimeter can only measure current, voltage, resistance, and cannot measure capacity. But you can roughly measure whether the lithium battery has insufficient capacity using a multimeter, which is to use the DC current range of the multimeter (preferably a pointer meter). Instantly measure the positive and negative polarity of the battery. If the current displayed on the meter is large, it indicates that the battery has capacity. If the displayed current is very small, it indicates insufficient battery capacity, but this method is a destructive measurement method. Actually, it's like short circuiting the battery to take a look. Therefore, contact should be made at all times during measurement. Absolutely not for a long time. Otherwise, even if it's a good battery. I also ran out of electricity.
Originally, a multimeter was not suitable for measuring the capacity of lithium batteries, but it is not impossible to measure, it is just unprofessional. Below is an introduction to the method of measuring the capacity of lithium batteries using a multimeter.
Equipment: Multimeter, small light bulb or high-power resistor, timer or mobile phone.
After the battery is fully charged, leave it idle for 2 hours, measure the no-load voltage, and record it. Connect a small light bulb or resistor and measure the current. It is best to control the current at around 1/10 of the capacity. Measure the current every hour, or measure the voltage and convert it into current. When it reaches 3.2V, measure the current and voltage every 10 minutes. Stop measuring until the voltage drops to the protection voltage to prevent damage to the battery caused by over discharge.
By adding up all the current times, the capacity of a lithium battery can be determined.
This is a more accurate measurement, and a rough measurement can treat the current as constant, simply using the middle value of the current * discharge time.
A multimeter cannot measure the capacity of a battery
But some friends also use a multimeter to test the size of the battery's short-circuit current and roughly determine the capacity of the battery. Pairing battery packs of the same specification using this method can still achieve good results, but some batteries have normal open circuit voltage. Once the short-circuit current is measured, the original form will be revealed.
Measuring short-circuit current (if the current value is within the allowable range of the multimeter and the battery) can only compare the power level of the same type of battery. Different models cannot be compared because the standard internal resistance of batteries of different models is different, and even if the power of the memory is the same, its short-circuit current is not the same.
