Testing of Battery Cranking Voltage with a Multimeter
The panel of the multimeter has three areas: display, function switch, measurement socket area, and probe socket area. A multimeter really lives up to its name. There are many things that can be measured, such as current, voltage, capacitance, resistance, etc. Today, we will have something special to give you a deeper understanding of a multimeter:
Detection of battery starting voltage:
Sedans usually use a 12V DC power supply system. First, turn on the multimeter and select the 20V DC voltage range. Place the red probe on the positive pole of the battery and the black probe on the negative pole of the battery, and read the voltage as the no-load voltage of the battery. If the position of the probe is reversed, a negative electromotive force can be obtained, which does not affect the measurement of the chestnut. It is generally believed that when the voltage is above 12.5V, it indicates sufficient battery power. When the voltage is insufficient between 11.5 and 12.5V, it needs to be recharged. When the voltage is below 11.5V, it indicates that the battery is over discharged or has an internal fault, and it needs to be checked before charging.
The no-load voltage does not indicate whether the battery is depleted, because the measured value on this day is the open circuit voltage of the battery, and no current passes through. The internal resistance of the battery does not share the electromotive force, so the measured voltage tk? Is high. When the actual battery is supplying power, the electrical equipment forms a circuit through the battery. The internal resistance of the battery will share a portion of the electromotive force, and as the battery discharges, its internal resistance continues to increase, and the internal voltage drop also increases, resulting in a decrease in the actual output electromotive force of the battery. Therefore, the inspection of battery starting voltage was introduced to check the output voltage of the battery under starting load conditions.
Firstly, turn on the multimeter and select the DC voltage of 20 on the multimeter. Place the red probe on the positive terminal of the battery and the black probe on the negative terminal of the battery. Start the engine and read the voltage value at the moment of engine starting as the starting voltage. The starting voltage should not be lower than 10V. If it exceeds 10V, it indicates a power loss and further testing of the power system is required to supplement charging.
