How to Test a Car Battery with a Multimeter
A morning nightmare starts with putting a key in the ignition slot and hearing an empty click. Of course, a dead battery is often responsible for such problems, and it may leave one stuck in a driveway in front of the house. At Arrowhead Imports, we know for sure how frustrating electrical failures in cars could be, especially when issues like charging Mercedes auxiliary battery are involved. However, we also know that regular testing of the battery can help to avoid towing services.
Using a Multimeter for Car Battery Testing
You don’t need to become a technician in order to maintain a healthy electrical system of the vehicle. A digital multimeter will cost only a few dollars, and it can easily show the exact voltage of a battery. In this way, a car owner will not experience unnecessary anxiety - you’ll know exactly how to test a car battery with a multimeter, and when it is necessary to visit an auto repair shop.
Although working with such technical tool might seem difficult at first glance, everything is simple enough. Many of our clients who were able to test their car batteries independently after visiting us. Today, we want to share some useful advice with you and show how it is possible to perform testing on a car battery with multimeter.
Safety Tips Before Testing a Battery with a Multimeter
Of course, there are many safety precautions to follow before doing anything else. For instance, park the car in a well-ventilated area. All headlights, dashboard lights, and radios must be turned off in order to avoid unnecessary power usage by electrical devices when using a multimeter for car battery testing.
Next, we suggest putting on safety goggles as a protection for eyes. Nitrile or rubber gloves are important too because car batteries contain dangerous acid. If the battery casing is damaged and leaking, the liquid may burn. In addition, it would be reasonable to remove rings, bracelets, necklaces, and other jewelry in order to prevent accidental sparks. It is also a good idea to keep hands steady and use a multimeter to test car battery only when the area around the battery is dry and clear.
Step-by-Step Instructions - How to Test the Car Battery with a Multimeter
Preparation
The first thing to do is to turn on a multimeter and set it to DC voltage. A healthy battery is capable of giving slightly more than twelve volts and, therefore, it is necessary to set twenty volts. This will ensure that the measurement is made properly and no fuse blows.
Connection
After setting the voltage to twenty, touch the red probe of a multimeter to the positive terminal. Usually, this part is marked with a "+" sign or even has a small cover painted in red color. Then, it is time to connect the black probe to the negative terminal.
Reading Results
Once both probes are touching the terminals, you’ll find a stable value on the display of a multimeter. Write down this number as it shows the current state of a battery. Then, it is time to disconnect the black probe and then the red one to turn off the device.
Interpretation of Results
After receiving a specific number on the screen of the device, you need to understand what this value means. A hundred percent charged battery displays a number equal to 12.6 volts or more. If one sees this number, the battery is okay and nothing is wrong with it.
If the number displayed by a multimeter ranges from 12.2 to 12.4 volts, it means that the battery is not charged completely - only fifty to seventy-five percent. Although the battery will be capable of starting an engine, it is necessary to charge it via highway ride or by connecting it to a charger.
Numbers lower than 12.0 volts indicate that a car battery needs to be replaced. At this stage, the battery is incapable of providing enough power to activate an engine. The batteries in this voltage range are usually useless and cannot be recharged.
Keep Your Electrical System Working Properly
Just a few minutes of checking the voltage of a battery will guarantee trouble-free driving for a while. Regular tests will allow you to replace a dying battery before being left without power and without a chance to go home. In addition, it is necessary to clean the battery terminals from corrosion regularly and ensure the battery holder is tight.
If you need help, be sure to contact our team at Arrowhead Imports!
Frequently Asked Questions
Is It Possible To Check A Battery Without Using A Multimeter?
Although it is recommended to use this tool because of the most accurate results, you may test a battery by turning on headlamps before starting an engine. If the lamps shine rather pale, the battery is weak and needs charging. However, it is better to test the battery using a multimeter.
How Often Is It Necessary To Check Car Battery?
We suggest testing your battery twice per year. Checking it in fall and in spring is enough to reveal weak units before extreme weather conditions cause battery failure.
Is A Multimeter Capable Of Telling Whether You Need A New Alternator?
Definitely, yes. By leaving the tool attached to terminals of a battery, you will see the actual voltage of the alternator that will change. If a car's alternator works properly, the voltage will be somewhere between 13.7 and 14.7 volts.