Is a 12.4 Volt OK for a Car Battery? (In-depth Analysis)

Published on: June 2, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

Are you preparing to put your automobile or boat in storage for the season? Care for your car engine properly and battery care is critical if you aren’t one of the lucky few who can use their devices all year round. In this piece of writing, we’ll explain if a 12.4-volt is OK for a car battery and discover the alternate options. Usually, it is considered wholly charged when the battery voltage reaches 12.6 volts or more. 

is a 12.4 volt ok for a car battery

Even a minor decrease in voltage on a car battery can significantly affect it. In the example of an automobile that drops from 12.6 to 12.0, the difference is 75%, and efforts declined from 100% to just 25% of what they were. The battery charge is 75 percent at 12.4 volts and 50 percent at 12.2 volts for cars.

Take into account a charged car battery at 12.4 volts or above and a depleted car battery at a voltage of 12.39 volts or less. So, is 12.4 V enough to start a car? It’s difficult to say because it’s considered discharged if the voltage drops below 12.39 volts. So, without further ado, here are the specifics.

What Is Battery Voltage?

Volts are a measurement of the battery’s electrical capacity. A 12-volt battery is the most common type of automobile battery found in today’s vehicles, like the Weize 12V SLA Rechargeable battery. Each of the battery’s six cells has a voltage of 2.1 volts at full charge. So you might be thinking, what voltage should a 12-volt car battery read when fully charged? Typically, at 12.6 volts or greater, an automobile battery is considered wholly charged.

Even a slight decrease in battery voltage significantly impacts the battery’s ability to perform its intended function. The specific gravity is assumed to be 1.265 when completely charged and corrected to 80°F. Also, it is essential to know what is the reserve capacity of a battery before determining the battery’s voltage. The table below illustrates how much energy is left in a battery when battery voltage measurement varies.

Battery VoltagePer Cell VoltsCharging State

Understanding the Different Stages of Battery Voltage

The voltage of all marine, automotive, solar and industrial batteries significantly impacts its duration. If you keep your battery charged up to maximum voltage, it’ll last considerably longer than if you keep it low voltage. To understand if 12 volts is too low for a car battery or not, you have to acknowledge different voltage levels. The battery’s voltage levels are summarized as follows:

Over a Volt of 12.6V

A healthy and completely charged 12.6V battery is all that is needed. There is no need to take any further steps.

A Voltage of 12.5V

We recommend rechecking your battery in a few days to ensure the voltage hasn’t decreased any lower. A safe battery charger is preferable if you think of charging the battery. Always follow the instruction manual before charging a car battery

Voltage Range of 12.1V to 12.4V

It would help if you used a reputable battery charger to recharge your battery, which is currently half-discharged fully. Your battery’s lifespan will be significantly reduced for long periods if it remains in this voltage range.

Less Than 12.0V

You should recharge your battery as soon as it reaches 12.0 volts, which is termed ‘flat.’ This voltage range will shorten your battery’s lifespan if you use it for an extended period.

Keep in mind: Please visit your local battery retailer for a free battery check after recharging your battery completely. Performing this test will allow you to determine if there is a problem with your car’s battery or charging system.

Chemical Reactions in Batteries

The chemical reaction in a battery produces the electricity that powers the device. You must first learn how to calculate battery life in order to know how long the battery will last. The electrolyte in a lead-acid battery combines with the battery’s active ingredient, which is a sulfuric acid and water mixture.

Sulfuric acid content has a significant impact on a battery’s voltage. The sulfuric acid weight percentage must be at least 35% to get 12.6 volts or above voltage.

Sulfuric acid and active material react to generate a new chemical as the battery is depleted and the sulfuric acid concentration decreases. As a result, the battery’s voltage gradually drops.

How to Know the Battery Volt

You should check your battery’s voltage to see whether it needs to be fast-charged or if the alternator is faulty. Alternators are often used because they produce a higher voltage than the battery. Different brands use different alternators like ACDelco 13597244 GM Original Equipment Alternator compatible with GM vehicles.

If you are in a hurry, it’s wise to know how long it takes an alternator to recharge a battery. To get the most accurate battery volt reading, you can use Astro AI Digital Multimeter, which is designed to troubleshoot a variety of automobiles. Always test 12 hours after turning off your car. Below are the steps you can follow to determine the battery volt.

Step 1-

Do not forget to turn your automobile off. In order to check the battery voltage, you’ll need a voltmeter;

Step 2-

Then remove the positive terminal cap and clean it if necessary. Then connect the voltmeter’s positive lead to the battery’s positive lead. The negative voltmeter lead should be connected just like the positive lead to the negative battery terminal. Your voltmeter is now ready to go.

Step 3-

Now observe the results. A fully charged battery reads 12.6-12.8 volts on a voltmeter. Your battery is healthy if your voltmeter registers 12.4-12.8 volts.

Step 4-

Any voltage exceeding 12.9 volts indicates that your battery has an excessive amount of voltage. If this is the case, use the high beams to remove any extra voltage surface charge.

Step 5-

If the voltmeter shows less than 12.4, charge the battery. You can “trickle charge” your battery if your voltmeter reads less than 12.2. The Suuwer Battery Trickle Charger is an excellent option you can choose. This implies charging your battery at a slower rate, avoiding the risk of overcharging it, causing excessive heat and off-gassing. If the needle doesn’t move at all, your battery is dead. It is possible to recharge a completely depleted battery by following a few simple steps.

Is 12.4 V Enough to Start a Car?

A lead-acid starter battery, like Weize 12V, with a voltage of 12.4 volts, isn’t awful, but it’s also not excellent. Once the battery has been charged, the voltage will drop back to the “charged and rested” 12.6 volts, although it can rise to as high as 13.3 volts for a short period.

What Voltage Should a Car Battery Show?

A fully charged automobile battery should be 12.6 volts. While driving, this voltage should be between 13.7 and 14.7 volts. A car battery should be replaced below at that voltage. Your car’s electrical system can be tested by starting it and turning on the headlights if you do not have a multimeter to determine the battery voltage.


1. How Many Volts Should a Fine 12-volt Battery Have?

Automotive batteries should be measured at 12.6 volts or above when fully charged, and they should read between 13.7 and 14.7 volts when the engine is running.

2. How Much Should the Voltage in a Car Battery Drop Overnight?

The voltage decreases to 12.7 within a few minutes and more overnight, indicating that the chemical reactions have slowed and stopped.

3. Do 12.2 Volts Start a Car?

A fully charged car battery should be 12.6v or higher when the engine is off. When the automobile is started at 12.2v, the battery is 50% drained. As soon as you turn the key in your car, the starter motor receives electricity from the battery.

4. What Voltage Does a 12-volt Battery Die at?

Fully charged and ready-to-go 12-volt batteries have a voltage range of 12.8 to 12.9 volts, while flat dead batteries have 12.0 volts. Therefore 12.4 volts on a resting battery suggest around 50% charged.

5. Is It Possible to Start an Automobile With Only 11.9 Volts of Electricity?

Despite displaying 12 volts, a flat battery will not start an automobile, and the battery is entirely drained at 11.9 volts. If the voltage is less than 12.2 volts, the battery is discharged, and the static voltage of a healthy battery should be 12.6 volts.

Final Verdict

The battery is your car’s lifeline, and you can’t move without a battery. So check your battery charge level or voltage often to ensure it lasts a few months. After reading this piece of writing, I hope there should be no more confusion regarding whether or not a 12.4-volt is OK for a car battery. 

Cars that are infrequently driven may require more frequent battery checks to ensure that the voltage does not fall below 12.5 volts, which is the point at which battery deterioration begins to occur more rapidly. It is wise to recharge the battery if the voltage drops below 12.5 volts.

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About This Writer

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Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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