The method of testing car battery failure with a multimeter
Every car has a battery, in fact, without a proper battery, the car will not go anywhere. But what if the car battery fails? How do we know that we need to replace the car battery? In the following, we will examine how to test the failure of the car battery with a multimeter. Stay with us.
How many volts should the car battery have?
A healthy battery should register about 12.6 volts when tested with a multimeter. It is therefore important to test the battery after at least one hour at rest to reach what is called the resting voltage. If you have used the car recently, the battery will probably show a higher reading than the resting voltage, which can be misleading.
Therefore, it is better to leave the car overnight and test the battery in the morning to get a really accurate measurement of the state of charge.
How to check car battery with multimeter?
Using a multimeter to test a car battery is easy. The first thing you need to do is make sure you can access the battery terminals, or in other words the battery head.
Batteries are usually located in the engine compartment on one side of the engine. If you can’t find the battery when you open the hood, refer to your vehicle’s owner’s manual. In newer cars, the battery often has a plastic cover that opens, or sometimes requires removing a few screws. There may also be a red cover on the positive (+) terminal that lifts or opens.
Once you have found the battery, be very careful not to touch the terminals with any metal objects as this will cause a short circuit and damage the battery, so do not place wrenches or other tools on the battery.
Car battery test guide with multimeter
the first A car battery breakdown test with a multimeter measures the DC voltage, which is indicated by a solid line and a dashed line above the letter V. Set the dial to 20, which will allow you to accurately measure between 0-20 volts.
Touch the red probe to the positive (usually red) terminal and the black probe to the negative (black) terminal. Terminals are marked with + and – signs. If you get a reading with a minus in front of it (-12.6 instead of 12.6), you have connected the terminals incorrectly.
The resting voltage should ideally not be less than 12.6 volts. Batteries that show a voltage of 12.2 volts are actually only 50% charged and are classified as discharged below 12 volts.
Understanding the amount of energy loss in the battery with a multimeter
One thing to keep in mind is that all modern cars experience losses, which is when an electrical current drains the battery even with the engine off. Therefore, systems such as clocks, computers, and alarms consume some energy. If you suspect that this will kill your battery during storage, it may be wise to disconnect the car battery or remove it completely.
If the multimeter shows less than 12.6 volts, disconnect the battery and fully charge it using a battery charger. Then let it rest overnight. If it holds a charge when it is not connected to the car, it means that something is draining the battery much faster than the computer memory and digital clock.
How to check car alternator with multimeter?
An alternator generates electricity and charges the battery. Not only that, but it also transfers power to the car’s electrical systems while you’re driving. Hence, its failure can be very troublesome. For more information about alternator failure, you can read the article on the signs of car alternator failure.
So, with the engine running, do the same battery test with a multimeter for the alternator. A healthy alternator should read between 13.8 volts and 14.4 volts. Any value that is outside this range and your car is under or overcharged will cause the battery life to be shortened.
final word
Correct and basic maintenance of the battery will cause you to need to buy a car battery later than expected. Therefore, it is necessary to know how to test the failure of the car battery with a multimeter so that when you suspect the failure of your battery, you can solve the problem well and be sure of the health of your battery.
Frequently asked questions on how to test car battery failure with a multimeter
- Can we do the test with a multimeter ourselves?
Yes, this task is not very difficult and by following the principles, you can easily test your car battery with a multimeter.
- When should the car battery be replaced?
Depending on whether it is sealed or atomic, the car battery has a life span of 3 to 5 years. Of course, this amount depends on many conditions that you can read 9 ways to increase the life of the car battery for basic maintenance and increase the life.
- Is testing with a multimeter the best test method?
This method is one of the best methods of testing car battery failure.
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