To measure the quality of the battery with a multimeter, follow these steps
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 certain known relationship between the battery voltage and the remaining power. Therefore, according to the capacity and use of the battery, the voltage across the resistor can be measured to see how much the voltage drops when the battery is loaded compared to when it is unloaded, and the battery power can be judged. .
However, the premise is that no load is applied, because after adding a load, the battery voltage will be distorted by voltage drop due to 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 results of the dry battery power.
2. A multimeter can also accurately measure the voltage of dry batteries. The battery capacity can be judged by measuring the voltage of the dry cell. Dry batteries include alkaline batteries and carbon batteries.
If the measured voltage is not less than the marked voltage of the dry cell, it means that the power of the dry cell is sufficient; the more it is less than the marked voltage of the dry cell, the more power the dry cell has lost.
Due to different models, the test results of dry batteries may be affected. However, for a single dry battery, as long as you are using an ordinary analog multimeter, select the maximum current range of the multimeter (0.5A-1A), and connect the negative meter lead to the battery. The negative and positive test leads should be quickly touched on the positive terminal of the battery. At this time, pay attention to the movement of the watch needle (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 both 1.5V. The battery power can be detected by measuring the internal resistance of the battery. First, measure the battery's off-circuit voltage, and then connect a load (such as a small lamp bead) to the battery. The battery's voltage will drop, and the voltage will be measured. The internal resistance of the battery can be roughly calculated by dividing the difference between the open circuit voltage and the loaded voltage by the working current under load. The larger the internal resistance, the smaller the battery capacity.
Note: Under normal circumstances, it is difficult to accurately measure the quality of the battery by directly measuring the battery voltage with a multimeter, unless the battery voltage is zero.
