How to measure the quality of the battery with a multimeter
1. First, select an appropriate load resistor, and then connect the load resistor in parallel between the positive and negative electrodes of the battery.
There is a known relationship between the battery voltage and the remaining power, so you can measure the voltage across the resistor according to the capacity and use of the battery, and see how much the battery voltage drops when it is under load compared to when it is no-load, and you can judge the power of the battery. .
However, the premise is that no load is applied, because after the load is applied, the battery voltage will be distorted due to the voltage drop caused by the internal impedance, and will gradually decrease at different rates over time, and will gradually increase after the load is removed. Therefore, if a load is applied, it will affect the detection result of the dry battery power.
2. The multimeter can also accurately measure the voltage of dry batteries. The power can be judged by measuring the voltage of the dry battery. Dry batteries include alkaline batteries and carbon batteries.
If the measured voltage is not less than the marked voltage of the dry battery, it means that the dry battery has sufficient power; the more the voltage is lower than the marked voltage of the dry battery, the more the dry battery is depleted.
Due to the different models, the test results of dry batteries may be affected, but for a single dry battery, as long as you use an ordinary pointer-type multimeter, select the maximum current range (0.5A-1A) for the multimeter, and connect the negative meter pen to the battery. The negative and positive test leads should be quickly touched on the positive pole of the battery. At this time, pay attention to the movement of the hands (short circuit current) to know how much power is left in the battery.
For two identical batteries at home, the measured open-circuit terminal voltage is 1.5V, and the battery power can be detected by measuring the internal resistance of the battery. First measure the open circuit voltage of the battery, and then connect a load (such as a small lamp bead) to the battery, the voltage of the battery will drop, and measure the voltage. The difference between the open circuit voltage and the load voltage is divided by the load current, and the internal resistance of the battery can be roughly calculated. The larger the internal resistance, the smaller the battery power.
Note: In general, it is difficult to measure the quality of the battery correctly with a multimeter directly unless the battery has zero voltage.
