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How to check a car battery simply and effectively

Batteries are an indispensable part of every car. 

It provides power to help cars start and maintain the operation of electrical equipment such as lights, air conditioners, sensors,…

When the battery fails, it will greatly affect the operation of the vehicle. To avoid potential risks, you need to perform regular car battery checks. 

In this article, we will give you the simplest and most accurate guide on how to check a car battery.

How to check a car battery


How to check a car battery

How to check a car battery


Car battery is the main part that provides the power supply for the electrical equipment in the car. 

If the battery is good, the electrical equipment on the car will work well. 

Therefore, you should regularly check and monitor the operating status of the battery for timely repair and replacement measures. 

Here are some commonly used car battery testing methods.


1. How to check the car battery preliminary with naked eyes


If you do not have specialized tools, you can check the car battery with naked eyes as follows:

+ Check the liquid level to see whether the extreme plate is too high or not (for water batteries):

The liquid inside the battery will evaporate over time by being electrolyzed into hydrogen and oxygen gases and then it evaporates out during each charge. 

Therefore, it is necessary to check the liquid level inside the battery, if the liquid level is lower than the specified level, it is necessary to refill the battery with distilled water. With naked eyes, we can check this liquid level very simply because car batteries often have a transparent structure.

+ Check the car battery to see whether it is swollen, its pile head is damaged, leaked, cracked or not.

These phenomena will appear when there are abnormal signs from the inside such as too high temperature, bottle, damage from the pole plates, etc. 

So if you see the above phenomena, it is best to hurry up. Quickly replace the new battery to ensure safe driving.


2. How to check the car battery with specialized equipment


In addition to visual inspection, you can use specialized tools to accurately check the operation of the battery, thereby taking timely maintenance or replacement measures. 

We would like to introduce to you the 3 simplest and most accurate ways to check car batteries:

+ Use a voltmeter

How to check a car battery

Voltmeter is a device widely used in testing car batteries. 

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The voltmeter is used to measure the potential difference between the two ends of the negative plate and the anode plate or other electrical devices. 

Here are the steps to use a voltmeter to test a car battery.

Step 1: Turn off the device. You must first turn off the car engine to ensure that the internal currents are stopped and to ensure the safety during inspection.

Step 2: Remove the battery positive terminal cover, then clean 2 battery terminals.

Step 3: Connect the positive pole of the voltmeter to the positive pole of the tank (usually the anode of a voltmeter has a red wire).

Step 4: Connect the negative terminal of the voltmeter to the negative terminal of the tank.

Step 5: Check the parameters on the voltmeter:

If the voltage measurement on the voltmeter is in the range of 12.4V – 12.7V, the battery condition is still good and it can be used normally.

If the voltage on the voltmeter is lower than 12.4V, the car battery needs to be charged.

In addition, if the voltage drops lower than 9.6V, the battery may be weak and it needs to be replaced.

+ Use a multimeter

How to check a car battery

A multimeter is a useful tool to check a car battery especially to see if there is a leakage or not. 

To check battery leakage with a multimeter, you should do the following steps:

+ Turn a power meter (electronic type – DMM – which can measure up to mA) to AMP measurement mode and make it connected in series with the battery.

+ Remove the (-) wire from the battery and connect it to the (+) end of the DMM.

+ Make sure the (-) end of the DMM is clamped to the (-) terminal of the battery.

+ Monitor and record the DMM’s Amp. Remember to wait for a while because some equipment on the car is completely discharged. 

When monitoring, if you see a current drop of about 0.050A (50mA) – 0.100A (100mA), it means the battery is still stable. If there is a bigger drop, your car is definitely leaking somewhere and it should be checked carefully.

+ Use a specialized machine

How to check a car battery

Currently, there is a method of checking car batteries with specialized machines. 

To apply this method, you have to take your car to a car service store as it’s a specialized machine. 

Normally, mechanics will apply the following steps:

+ First, connect the machine to the battery

+ Then connect the red clamp to the positive terminal of the tank

+ After that, connect the blue clamp to the negative terminal of the tank

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+ Next, proceed to select the location of the tank, the type of battery pile, the type of battery to use, the standard of the tank and the test standard, the parameters on the tank in turn according to the machine.


Experience in helping car batteries operate stably and sustainably


It’s undeniable that having a guide on how to check a car battery up your sleeves is super convenient as you can take better care of your car. 

However, learning how to take care of your car battery is also equally good as you can prolong its lifespan. 

To increase the durability, time of use and stable operation of the car battery, you should pocket the following notes:

+ For water batteries, regularly check the liquid level in the tank: if it is lacking, it is necessary to add more solution immediately. 

To ensure maximum safety, it is best to bring your car to a reputable car care and maintenance center for the most accurate inspection.

+ Regularly check and maintain the car battery.

How to check a car battery

You should avoid starting too much and traveling too short because this will reduce the capacity in the battery quickly, making the battery quickly degrade and shortening its life.

+ Start the car 30 minutes to 1 hour a week or every 3 to 5 days to ensure the performance of the engine and equipment on the vehicle when you don’t use your car for quite a period of time. 

How to check a car battery

This also helps increase the life of the battery.

+ Park under the roof: Leaving your car under direct sunlight for too long is absolutely not recommended. 

How to check a car battery

Because at that time, the temperature in the car increases which affects the components and internal structure of the battery and leads to damage, weak power, difficult to start the car,…

Therefore, when parking the car , you should choose places with shade, a roof, or use insulating tarpaulin to cover the car.

+ Do not install too many devices on the car, because this will make the battery run out of power quickly, and the battery life will also decrease quickly.

+ Remember to turn off devices before getting off the car such as lights, air conditioners, radios, etc. And always make sure electrical equipment works according to specifications on the vehicle.

+ Regularly clean the tank and its terminals. If not regularly cleaned, dirt will become conductive materials and reduce the performance of the battery.

+ Clean the engine compartment every 6 months.

If there is a need to replace the battery, you should learn and choose for yourself a reputable and genuine supplier. 

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Because on the market today, there are many types of batteries of poor quality that easily deceive consumers.




Hopefully, the information shared above helps drivers have more ways to check car batteries to soon recognize the status of the battery and to avoid awkward or risky situations while using the car. 

If you have any questions or need advice, you can contact us directly for the most detailed and accurate answers.




How do I know when my car needs a new battery?


According to car experts, you will know that your car is calling for a new battery when you notice the following 7 signs. 

The first one is a slow starting engine, which means that it’ll take you more time to start your car than usual. 

The second one is dim lights and electrical issues. 

The third one is the check light engine being turned on. 

The fourth one is a bad smell like something scorchy. 

The fifth one is corroded connectors. The sixth one is a misshapen battery case and the last one is an old battery.


How long can a car battery last without driving?


According to the AA, a car battery in good condition is really strong. 

It can operate in a two-week time or even longer without needing a recharge. 

However, the AA also recommends that even if you don’t use your car for a while and the battery can work in at least two weeks, you should crank it up once a week to recharge it. 

This will help to keep your car battery from being too low on energy, which is no good for it in the long run.


Can a completely dead battery be recharged?


Yes, a completely dead battery can be recharged on one condition: that dead battery has been revived by a jump start. 

There are several ways you can apply to recharge a dead battery. However, there are two methods that are considered to be among the simplest. 

The first trick you can try is to drive your car around for a few drives. If it doesn’t work, you can try plugging your car battery to a charger. 

If you try this one, remember that you should leave the recharging process lasting for about 24 hours so that your dead battery can be fully recharged. 

Both these two ways are easy and affordable to take on.

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