Using a multimeter to test batteries
1, first of all, to select an appropriate load resistor, and then connect the load resistor in parallel between the positive and negative terminals of the battery.
Battery voltage and the remaining power there is some kind of known relationship, so you can be based on the capacity and use of the battery, and then measure the voltage at both ends of the resistor, to see how much the battery voltage drops when the battery is loaded compared to when it is unloaded at this time, then you can judge the power of the battery.
However, the premise is not to apply any load, because after adding a load, the battery voltage will be due to the internal impedance caused by voltage drop distortion, will be gradually reduced at different rates over time, and after removing the load gradually higher. Therefore, if a load is applied, it will affect the results of the dry battery power test.
2, multimeter can also accurately measure the dry cell voltage. You can judge the power level by measuring the voltage of the dry cell. There are alkaline batteries and carbon batteries.
If the measured voltage is not less than the labelled voltage of the dry cell, it means that the dry cell is sufficient; the more the voltage is less than the labelled voltage of the dry cell, it means that the dry cell is losing more power.
Due to the different models, the dry battery test results may be affected, but for a single dry battery, as long as the use of ordinary pointer multimeter, the multimeter will be selected maximum current gear (0.5A-1A), the negative pen to the negative terminal of the battery, the positive pen should be in the positive terminal of the battery to quickly touch, at this time, pay attention to observe the movement of the needle (short-circuit current), you know how much power is left in the battery.
Two identical batteries at home, measuring the open circuit voltage are 1.5V, you can measure the internal resistance of the battery to detect the battery's power. Firstly, measure the open circuit voltage of the battery, then connect a load (such as a small lamp bead) on the battery, the voltage of the battery will drop, and measure the voltage. The difference between the open circuit voltage and the voltage with a load divided by the current working with a load, you can roughly calculate the internal resistance of the battery, the larger the internal resistance of the battery the smaller its power.
Note: In general, directly using a multimeter to measure the battery voltage, it is difficult to correctly measure the battery good or bad, unless the battery zero voltage.
