How To Test A Car Battery With A Multimeter

The car’s battery is one of the most vulnerable items. It can drain very quickly and can be very expensive to replace. Moreover, a weakening car battery can give rise to many problems, such as delayed ignition, dim lights, etc.

It’s necessary to test your car battery frequently. While there are many ways to check the status of a car’s battery, one of the best options is to use a multimeter. You can also check the battery’s status with a battery tester or an OBD scanner that offers a battery testing feature. However, if you want to keep it old school, then here’s how to test a car battery with a multimeter:

Note: A healthy battery will show a voltage of 12.6 volts on the multimeter.

Preparation Before Testing Your Car’s Battery

Here's where you can find out how to test a car battery with a multimeter
In this article, you will know about how to test a car battery with a multimeter

Before you test your battery, make sure you are wearing gloves so that your hands don’t get messy. Avoid wearing anything made up of metal, including rings and chains. They can cause you to get injured.

Dry your body, especially your hands, carefully. Also, ensure the surrounding is dry, especially the ground. Do not test the battery if it’s too hot. Allow it to cool before testing it out.

How To Test A Car Battery with a Multimeter: Step By Step Guide

Here are three simple steps to perform a car battery voltage test:

Three simple steps to test a car battery with a multimeter
How to perform a car battery voltage test with a multimeter

Step #1 – Locate The Battery

The battery is kept in the engine bay at the side of the engine. Therefore, you need to open the hood to get access to it.

Once you find the battery, remove its cover. In some modern cars, there’s a plastic wrap on the battery for protection. It can come out with a little pull. However, in some cases, there may be some screws. Remove them, and you’ll be able to access the battery.

After removing the cover, you’ll find two terminals on the battery: a positive (+ve) terminal and a negative terminal (-ve). The +ve terminal typically has a red cover that you will have to lift off.

Step #2 – Attaching The Multimeter Probes

Once you can access the terminals, it is time to make a connection. Take the red probe and attach it to the positive terminal and the black probe to the negative. If you do it wrong, the multimeter will show a voltage of -12.6 rather than 12.6. If it does, inter-swap the probes.

Step#3 – Checking The Volts

As you attach the probes, the multimeter will display a reading. Here is how to test a car battery and see if it is charged or not:

  • If it’s 12.6 volts, it means the battery is fully charged.
  • Volts below 12.6 and 12.2v imply that the battery is half charged.
  • Voltage measuring below 12.2v means that the battery is discharged.

 If it shows volts below 12.6v, pull it out and charge it with a battery charger or take it to a professional.

Car Battery Voltage Chart

12V Battery VoltageVolts Per CellCharge
12.72.12100%
12.52.0890%
12.422.0780%
12.322.0570%
12.22.0360%
12.062.0150%
11.91.9840%
11.791.9630%
11.581.9320%
11.311.8910%
10.51.750%

How To Tell If Your Car Battery Is Bad?

Many warning signs will tell you if there’s something wrong with your car’s battery:

After you test a car battery, here are some most warning signs that show you have a bad car battery
Four common signs that show you are having a bad battery

Poor Engine Crank

When you turn the key to start the ignition, it is the battery that ignites the engine. However, if the battery has weakened, drained, or lost the charge, it will produce a lazy and slow engine crank.

On the other hand, a healthy battery will turn the engine on in one go and only produce a rapid clicking sound.

Warning Light On The Dashboard

Modern cars have a battery status icon on the dashboard that lights up when the battery is weak. It can help you judge the status of the battery. However, when the battery light is on, it doesn’t mean that your battery must have gone bad. There may be a problem with the connection or some electrical component.

Expanded Battery Case

A battery works by triggering a chemical reaction in its box. Sometimes, outside elements such as heat or cold, a lack of charge can cause the battery’s walls to expand. We see this in TV remotes as well. When we do not use the remote for a long time, the battery often gets swollen. This problem happens because the battery discharges due to extreme cold or hot. The same is the case with a car battery.

Old Battery

The lifespan of a battery is 5-6 years. If it has lived its age and is reeking a strange smell, something has gone wrong with the battery, and it needs replacing.

The Conclusion

It is crucial to keep the battery in good shape. When you keep your battery well maintained, it will run smoothly and longer and provide enough juice to power all electrical components efficiently.

It is an excellent choice to check your battery’s status with a multimeter. The process is straightforward and only takes a few seconds

Read more: Best Battery Testers Review and Comparison 2021

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