DIY Basics: How to Test Your Car Battery

Your favorite car has been a reliable ride for years. It’s getting older now, however, and minor issues have been on the rise. You might be questioning the car’s battery and if it’s still viable. There’s no reason why you should take the car to a mechanic for this simple check. Learn how to test a battery with a multimeter by following these basic steps. You’ll have a clear picture of the issue at hand afterward.

1. Allow the Car to Cool Down

The anatomy of a battery¬†allows it to charge and discharge as it offers power to the car. With this fact in mind, it makes sense that the value measured with a multimeter will vary based on the battery’s previous use.

Get a clear view of the battery’s voltage by letting the car rest for at least an hour. You might park it overnight and test battery with multimeter in the morning. The resting voltage tells you if the battery is good or bad.

2. Reveal the Battery’s Terminals

Knowing how to test a battery includes the understanding of the terminals. Every car battery has positive and negative terminals. Once connected to the car, electrical current flows between the terminals as the battery activates the ignition system.

  • Locate the terminals under plastic or rubber covers. Some vehicles have screwed-on caps as alternative protection.
  • Carefully remove the covers. Keep any metal objects, such as hand tools, away from the terminals. They can shock you. You can keep the wires connected to the terminals as you test car battery with multimeter.

3. Set the Multimeter

Every multimeter has many modes available on them as you learn how to test a battery. The simplest setting is at 20 with a DC voltage. This setting is typically indicated with a solid line followed by a dash. A large “V” is above or below this symbol.

Be sure to find this setting as you learn how to test a car battery with a multimeter. It allows you to measure up to 20 volts. Other settings produce various decimal-point changes. The reading won’t be very accurate. A precise reading tells you if the battery is being drained or operating at peak levels, reports Cars Direct.

4. Position the Probes

Positioning the probes on the terminals is a big part of how to check car battery. It’s the same strategy for other power sources, including marine and golf-cart batteries.

  • Clip the black or negative probe onto the battery’s negative terminal. The colors and symbols should match up.
  • Perform the same connection with the positive or red side. Regardless of the power within the battery, you should have a positive reading. A negative symbol indicates that the probes aren’t positioned on the terminals as they should be.

5. Verify the Reading

When you know how to test a car battery, you also understand the voltage that you’re looking for on the multimeter. A strong battery reflects a 12.6-volt reading. Some readings may not be that exact, such as 12.58 or 12.57 volts. In essence, you have a perfect battery.

If you find the reading to be around 12.2 or 12.3 volts, it’s about 50-percent discharged. Any values below 12 volts are cause for concern.

6. Make the Final Decision

Remove the probes and shut off the multimeter. Consider the voltages that you recorded. You may want to charge the battery outside of the vehicle if it reads 12.2 or 12.3 volts. Replace batteries that are less than 12 volts in charge. When you know how to check car battery, there’s no reason to keep dealing with an aging battery that will fail in the near future.

For any other questions surrounding batteries and test parameters, contact Northeast Battery today. We have a full staff of professionals who understand the ins and outs of the average car battery. Learning how to test a car battery gives you solid insight into the power source. You can now be sure of any swaps when they become necessary tasks within the car.