How to measure lithium battery capacity with multimeter
Strictly speaking, a multimeter can only measure current, voltage, and resistance, but cannot measure capacity. But you can use a multimeter to roughly measure whether the lithium battery capacity is insufficient, 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 high, it indicates that the battery has capacity. If the displayed current is very small, it indicates that the battery capacity is insufficient, but this method is a destructive measurement method. Actually, it's like short circuiting the battery and taking a look. Therefore, contact should be made at all times during measurement. Absolutely not for a long time. Otherwise, even with good batteries. Also let out the electricity.
Originally, a multimeter was not suitable for measuring the capacity of lithium batteries, but it is not impossible to measure it, it is just unprofessional. Below is an introduction to the method of measuring the capacity of lithium batteries with 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 approaches 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 from over discharge.
By adding up all the current times, the capacity of the lithium battery can be determined.
This is a more accurate measurement, and a rough measurement can consider the current as constant, using the discharge time at the midpoint of the current directly.
A multimeter cannot measure the capacity of a battery
But some friends also use a multimeter to test the short-circuit current of a battery and roughly determine its capacity. When paired with a battery pack of the same specification, the effect is still good. However, some batteries have normal open circuit voltage, and once the short-circuit current is measured, their true form will be revealed.
Measuring short-circuit current (if the current value is within the range allowed by the multimeter and the battery) can only compare the power of batteries of the same model. Different models cannot be compared because the standard internal resistance of batteries of different models is different, and even if the amount of memory is the same, their short-circuit current is also different.
