1. Drive the car for a while and then let it rest

To get a totally reliable measurement it is necessary that the car has been in operation before. It’s recommended to drive it for 40-50 minutes and then letting it rest the same time will be enough.

2. Measure the battery with the vehicle stationary

The first measurement we will make will be with the engine completely stopped. Having let it stopped (about 4 hours), you will measure the battery voltage, which should be between 12.5 and 12.9 volts. To do so we remove the key, connect the multimeter in direct current to the battery terminals and write down the value marked by the multimeter.

3. Check the battery with the car idling

Then we start the car and leave it in neutral. After that, we reconnect the multimeter in direct current to measure the battery and write down the value it marks.

3. Testing the battery with alternating current

Perform the same measurement with the car idling, but this time change the voltage of the multimeter to alternating current and record the result.

4. Determining if the battery should be changed or not

We look at the results of each measurement and check if they meet these conditions to see if it is necessary to change the battery.

5. Looking for other possible battery failures

Even if the battery passed this small test, it could be damaged for some other reason. To know it, we will check other values and compare its general performance.

Depending on the use, the battery may also last more or less. This can be checked more easily in a gasoline car, since the engine will make a strange sound when starting, while in diesel the car will not start without more.