Car Battery Test With Multimeter

It is important to know how to test a car battery with a multimeter for normal battery issues. Imagine, if you had to travel to a remote area, only for the car battery to fail without the sign of a mechanic in the vicinity. This can be a big blow and you might wish that you had tested your battery and the electrical system earlier on.

Testing a battery with a multimeter is very easy and fast. Normal battery issues include corroded terminals, battery case damage, acid buildup, and cell problems. These can be handled by cleaning the battery. A multimeter will help you to know the state of your battery and tackle the problem very fast.

Car Battery Test With Multimeter Guide

In this guide, we will assist you to know how to use a multimeter to troubleshoot your car battery issues.

To begin with, you should identify where your car’s battery is fitted. A good number of cars have their battery placed in the engine compartment under the hood. Other car brands have the battery housed in the trunk. Then, check the battery terminals and cables for corrosion. Corrosion usually interferes with multimeter readings. Wipe off the corrosion by using a battery-terminal cleaner and a terminal brush. If there are any loose cables, tighten them using a Philips head screwdriver.

After the battery is exposed, ensure that no metal touches the terminals. Then, insert the multimeter leads into the right connectors on the multimeter. The black lead belongs in the black-colored connector which is labeled as “COM”. Place the red lead into the red connector labeled volts, ohms, milliamps.

When you want to measure DC voltage which normally has a solid line and a dashed line above a letter V, set the dial to 20. This will enable you to accurately measure between 0-20 voltages. Hold the red probe to the positive (+) terminal, and the black probe to the negative (-) terminal.

In case you record reading with a minus in front of it such as -12.6, then you have got the wrong probes. The resting volt should be no lower than 12.6V. Also, note that if a battery goes below 12.2V it’s actually just 50% charged, and above 12V it’s rated as discharged. If the battery is well charged and healthy, it will read 12.6 volts. This is because of the output sum of six 2.1-volt internal cells.

Get a person or a friend to help you crank the engine while you read the multimeter. The voltage shown on the multimeter shouldn’t be anything less than 10.0 VDC while the key is in the start position. If you get a reading of below 10.0 VDC when starting your car, this is an indication that the battery is not producing enough current to reliably handle the starter motor’s current draw.

Moreover, if the car is running when the battery is being tested with a multimeter, the charge from the powered alternator will skew proper readings. So, when testing the car battery, you should turn the car off.

Bottom line

When carrying out a test on your car battery using a multimeter, you always place the multimeter leads on the battery terminals swiftly and firmly. If the connection is loose, this might lead to a startling electric arc. Also, never allow any object to make contact with both cables and battery terminals at the same time.

With the above guide, you can now acquire a quality multimeter and know the status of your battery before going out. This can save you from being disappointed when the battery fails at a crucial time or place.


Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top