The method is to measure twice. The specific operation method is: Before the vehicle starts, measure the no-load voltage of the battery with the voltage range of pointer multimeter. Generally, the rated voltage of passenger car batteries is 12V, and the no-load and no-load voltages are usually around 13V. If the voltage is obviously low, it means that the health of the battery is not optimistic.
Step 2: At the moment when the person inside the car tries to start the vehicle by manipulating the key, the person outside the car observes the multimeter pointer. If the battery voltage is lower than 10V at the moment when the starter works, it basically means that the battery life will not be long. This is because the instantaneous large current voltage drop of the battery is large, which reflects that the battery cannot withstand the output of severe large current.