How to Use a Multimeter to Test a Car Battery [2022 Guide]
Testing your car battery and the entire electrical system is an important part of routine maintenance, not only when a problem becomes apparent. Performing a regular test will minimize the likelihood of encountering a problem. It will make sure that your car will be running smoothly.
To test your car battery, there is one important tool that you will need – a multimeter. If you want to know how to use a multimeter to test a car battery, read on and we’ll let you know the easy way to do it. There is no need to be a pro to do it right! Anyone can ensure the best state of their battery with the use of a multimeter.
What is a Multimeter?
Before we proceed, let us first have a quick look at what exactly is a multimeter and why it comes as a handy tool.
At its most basic, a multimeter is a dedicated tool that comes with two detachable cables. It has negative and positive tips. There is also an on and off adjustment knob in front of the unit. There is a small screen on the top that will show the exact reading.
To be more technical, it is an electronic tool that is used for the measurement of resistance, amps, and voltage across circuits. They can be either analog or digital. Their main purpose is to test for any fault or diagnose an existing problem.
How to use a Multimeter to Test a Car Battery
Now, let us go to some of the easy steps that you have to follow to make the most out of a multimeter in testing the battery of your car.
Locate the Battery
Obviously, the first thing that you have to do is to search for the actual location of the battery. Most will be in the engine compartment, although there are also some batteries that are in the trunk.
Before performing the test, inspect the battery, making sure that it is in good condition. There should be no signs of corrosion or build-up of crusts. Clean any dirt that you can see before the test. If there are loose cables, make sure to tighten them.
Get the Multimeter Ready
Now that you have located and cleaned the battery, the next thing to do is to prepare the multimeter. Select the DC Volts in the multimeter. Before you start, you also have to make sure that the setting is at 0.
Start Testing the Battery
Before you start, make sure that the engine is turned off. The readings will not be accurate if you test the battery while the engine is running.
Put the red lead on the positive terminal of the battery and the black lead on the negative terminal of the battery.
Read the Display
This is usually the trickiest part of the process and you will need a reference to know if the battery is working properly.
If the reading shows 12.6 volts, this means that the battery is fully charged. On the other hand, if it is 12.4 volts, the battery is 75% charged. It is 50% charged if the reading is 12.2 volts, 25% charged if it shows 12 volts, and when it is 11.9 volts and below, it has effectively zero charge.
If the battery is less than 12.6 volts, it is recommended that you disconnect it, and have it charged to ensure its optimal functionality and minimize frustration while on the road.
#Video: How to Test a Car Battery with a Multimeter
Tips to Keep in Mind
Now that we have discussed the easy steps that are involved, below are some of the most important tips to keep in mind:
- You should put the leads of the multimeter on the battery terminal as quick and firm as possible. If it is loose, the reading may be inaccurate.
- Pay attention to your clothing before you start. See to it that you are not wearing anything that is loose, including accessories.
- See to it that no metal parts will be touching the terminals of the battery. This can be a significant risk as this can lead to an explosion.
- As noted earlier, you have to clean the connectors before you start. If there are signs of corrosion or build-up of dirt, use a sandpaper to have them cleaned. Spraying a WD40 will also work to prevent rust from forming in the future.
How to test a car battery
As shown in this guide, using a multimeter in testing your car’s battery is an easy task that can be accomplished by almost anyone. All that you need is to invest in the right product and religiously follow the steps to ensure the accuracy of the readings.