The worst possible moment to being stranded could be caused by a weak or dead car battery. This can be prevented by routinely checking the condition of your battery with a voltmeter, a cheap and easy tool.
This useful tool detects voltage and assists in determining whether your battery has sufficient charge to start your car consistently. To make sure your car is always ready for the road, we will show you how to use a multimeter to check the battery in your car.
What You Need:
- Digital Multimeter (preferably with a voltage setting)
- Car Battery (in your vehicle or disconnected for testing)
Step 1: Set Your Multimeter to the Correct Voltage
Make sure your multimeter is set to the DC Voltage setting (V with a straight line, not AC voltage) before you begin testing the car battery. To obtain a correct measurement, put your multimeter to the 20V range since most car batteries have 12-volt systems.
Step 2: Turn Off Your Car
Make sure your automobile is completely off for safety. This guarantees that the voltage value you obtain accurately represents the battery’s resting voltage, as opposed to a voltage impacted by the alternator or other systems.
Step 3: Access the Car Battery
Find the battery in your automobile under the hood. To reach the terminals on your battery, you will need to remove any protective coverings that may be on it. There will be two terminals on the battery:
- Positive terminal (marked with a plus sign “+” or a red cover)
- Negative terminal (marked with a minus sign “–” or a black cover)
Step 4: Attach the Multimeter Probes
Red probe to positive terminal: Attach the red multimeter probe (which is positive) to your car battery’s positive terminal.
Black probe to negative terminal: Attach the black multimeter probe, which is negative, to your automobile battery’s negative terminal.
To obtain an accurate reading, make sure both probes are making excellent contact with the metal on the battery terminals.
Step 5: Read the Multimeter
View the multimeter’s display after the probes are connected. A completely charged, healthy automobile battery should have a voltage reading of 12.4 to 12.6 volts.
Understanding the Reading:
- 12.6V or higher: Your battery is fully charged.
- 12.4V to 12.6V: The battery is in good condition but might not be fully charged.
- 12.2V to 12.4V: Your battery is somewhat undercharged and might need recharging soon.
- Below 12.2V: This indicates a weak battery, and you should consider charging or replacing it.
Step 6: Check for Voltage Drop While Cranking
You can also observe how the battery responds to engine cranking if the voltage appears to be OK but your car is still having difficulties starting. To carry out this:
The multimeter probes should remain attached.
As you keep an eye on the multimeter reading, start the automobile yourself or have someone else do it.
The battery voltage should decrease during cranking, but it should not drop below 9.6V. If it falls below this point, your battery could not be holding up well enough to power the starting and might even be nearing the end of its life.
Step 7: Check the Alternator
You might as well see if your alternator is correctly charging your battery while you have your multimeter out. To carry out this:
Leave the engine running after starting the vehicle.
The multimeter should read between 13.7V and 14.7V when the engine is running.
This indicates that the alternator is effectively charging the battery.
An alternator problem can exist if the reading falls or rises outside of this range.
Conclusion
Using a multimeter to check the status of your car battery might help you stay out of trouble if it becomes weak or dead. A properly charged battery should have a reading between 12.4 and 12.6 volts; if it is less than 12.2 volts, you may need to replace or recharge it.
Make it a practice to check your battery on a regular basis, particularly before lengthy travels or in the winter when batteries have to work harder. You can keep your car in good working order and stay ahead of any potential problems with this quick inspection!