How Long Does It Take To Charge A Car Battery – An Expert Guide


Whenever your car battery runs out, you need a sufficient charge to rejuvenate it. Fortunately, we have outlined the options available when your car battery needs to be charged.

We also focused on different types of chargers, the charging time, depending on the ampere and voltage, and some other useful information that will determine the time it would take to charge the car battery. “How long does it take to charge a car battery?” It is a question often asked by many car owners.

The time to fully charge a 12-volt car battery will depend on the amperage of the charger used. Compared with low-amp chargers, high-amp chargers require less time to charge your car battery.

On the other hand, if you want to keep the car battery at a fully charged level, it is better to use a low-amp charger than a high-amp charger. To know exactly how long does it take to charge a car battery, let’s take a closer look at the following information?

What are the Determining Factors?

If you want to know how to charge a car battery, the most crucial detail is arguably the real reason for the need to charge the battery. Why does your battery need to be charged in the first place? There are many reasons, and it may be that the battery cannot provide enough power for the car.

The earliest reason may be that the battery is getting old in the car. The second reason is that certain parts are damaged because corrosion and cold weather is causing wear and tear of the various engine parts. If the battery is damaged but still working, it can be charged. However, if the charging method does not work, you may have to consider replacing it. If you decide to buy new car batteries, you can sell the old battery for more cash too.

Different Types of Car Battery Chargers 

Depending on the type of charger used to charge the battery, the full charge schedule can vary greatly. It can take an hour to a day to charge a car battery-it all depends on the battery type in your vehicle and the charging method you choose as well.

car battery charge time calculator

Linear Charger

The simplest way to charge a car battery with a charger is through the use ofa linear battery charger. It allows you to power the battery through a wall outlet in a simple way. However, the simplest method is not the fastest method. Since there are few settings and power sources required, the charger has a low operating current and may take a long time to charge the battery.

The cheapest version of this method is a Repco brand battery charger, which is only 2.7 amps. Repco needs up to 12 hours to charge the 12-volt lead-acid batteries in most cars. The linear battery option will continue to charge the battery, and there is no controller to stop the charging process when the battery power reaches its peak. If you ignore the battery level and the time to replace the battery, the life of the battery may be damaged. In some cases, it may cause the battery to explode or malfunction.

how long does it take to charge a car battery at autozone

Multi-Level Battery Charger

Multi-level battery chargers are more expensive than linear options, with prices ranging from US$90 to US$110. Compared with the linear battery charger, the multi-stage version can charge the battery in bursts instead of continuously. This is better for the battery cell and can prevent long-term damage caused by the linear option during continuous charging. Multi-level chargers are also called smart chargers, which may be due to the burst charging method and higher amperage. You can purchase up to 50 amps of multi-stage chargers, which allows you to charge the car battery in less than an hour.

how long to recharge car battery after jump

Trickle Chargers

The trickle current charger is the last charger you can choose, which can work in the current range of 0.8 amperes to 4 amperes. They operate at low power output levels and do not charge the battery when it goes dead. However, if you connect it to the battery when you are not using the vehicle, they are useful to prevent battery problems. 

Enhanced flooded batteries, also known as EFBs, are ideal for fast charging and running at low voltages for use when the vehicle is not running or the battery is not entirely depleted. Though the stream charger can keep the battery in normal working condition, it may affect the time required to charge the car battery.

What is the required duration to charge a 12-volt car battery?

The time required to charge a 12-volt car battery depends on the amperage you use to charge the battery.

Duration using 40 amps 

Forty amps can quickly charge your car battery, even within a few minutes after the start-up process. Make sure you don’t overcharge the battery, as this will damage the battery and affect its service life and efficiency during long-term use.

Duration using 12 amps

Before using a 12-amp charger, make sure you are not charging from a circuit with multiple outlets and devices. Before choosing this version, please figure out the circuit breaker and wiring on the socket. The best case for a 12-amp charger is that when using a 12-amp load, you can get a charging range of 5 miles per hour.

Duration using ten amps

A 10 amp charger can charge a half-discharged small car battery in about 2-3 hours. Small car batteries are classified as RC 40-60. The charger can charge a 50% discharged medium battery RC 60-85 in about 3 to 4 hours, or a large RC 85-190 battery in about 4-7 hours. If the battery is completely discharged, double these times to see how long it takes to charge.

Duration using four amps

Car batteries usually hold 48 amps, so it takes about 12 hours to charge with this voltage fully. This may be the right choice for setting the car battery for a long time to maintain a certain charge level.

Duration using two amps

It takes 1-2 days to charge a battery using a two amps charger fully. This is usually because a 2 amp battery provides 1 amp per hour. This type of amp power is generally used when performing a trickle charge or keeping the battery at a certain level. If you want to extend the connection time between the car battery and the charger. Or you don’t usually drive the car regularly, using a 2 amp battery charger may be the right solution.

How Long Does it Take to Charge a Car Battery at 40 amps?

If you want to charge car batteries quickly and efficiently, a 40-amp charger is the right choice. Even if your battery is completely exhausted, your car will be able to start within a few minutes after connecting it to a 40-amp charger. It is also a handy item you should carry when travelling because it can quickly charge a depleted battery and help you get started promptly to charge a car battery with jumper cables.

Note: You should be aware that connecting the charger for a long time may damage the battery. If the charger you are using is a smart charger, when your battery is fully charged from 40 amperes, it will automatically reduce the amperage immediately and wholly shut down. Therefore, these smart chargers are the best choice for purchase.

How Long Does It Take To Charge A Car Battery

How Long Does it Take to Charge a Car Battery at Four amps?

Generally, a deep cycle battery can usually hold 48 amps. So if it is charged at 1 amp, it will take 48 hours. Similarly, if you charge a car battery with a charger at 4 amps, the total time to fully charge the battery would be approximately 12 hours. Therefore, if you need a fast charger, a 4 amp charger is not the right choice for you. However, this charger is very suitable for smaller batteries.

If you want to maintain your car battery or keep it on low amperage for a long time, using a smart 4-amp charger is ideal. The charger will charge less-used batteries like a trickle charger, and then automatically turn off when fully charged. It would then turn on again when the battery power drops below a fixed level.

how many miles to charge a car battery

How Long Does it Take to Charge a Car Battery at 2 amps?

Using a 2 amp charger will take you quite a long time to charge the car battery to an acceptable level. The average time to charge a 48-amp battery is 24 hours at most. Therefore, this type of charging is usually used as a-stream charging or to maintain the battery in a possible state of charge, rather than trying to fast charge to strengthen the battery and make it start your vehicle.

When you plan to keep the battery connected to the charger for some time, using 2 amps is an adequate amperage. It also works great for a battery that is rarely used, just like an antique car that will be driven occasionally. The smart 2 amp charger can also help maintain the charge in the battery, so you can always be set to drive smoothly.

how long to charge car battery while driving

How Long Does it Take to Charge the Car Battery with Trickle Flow Charging?

If you want to park your car in the garage for a long time, a trickle charger is an excellent choice to charge a battery. These chargers usually run at approximately 2 amps, and it may take at least 24 hours for the 48 amp battery to reach an acceptable level, depending on the condition of the battery. The main function of the trickle flow charger is to keep the car battery-powered, and as well keep its power from running out. The trickle charger takes a long time to charge the battery fully, and will automatically turn off when it is fully charged.

When repairing or maintaining other parts of the car, the mechanics in many workshops often use trickle flow chargers to maintain the battery, especially if the battery has to be disassembled for a long time. Therefore, the battery will have enough power to be ready to work when it is installed.

charging of a battery

How Long Does it Take to Charge the Car Battery While Driving: Fact Investigation? 

Charging a car battery is a task that cannot be ignored. This is why it is vital to charge the car battery when needed. A person can charge the car battery by driving, though this is dependent on two factors:

Car Life Cycle

The first factor that may cause a car’s battery to run out is the car’s life cycle. If the vehicle is not used for a long time, the battery is quickly exhausted. It is generally known that when you accidentally leave the AC power or car lights on all night, car batteries will run out. In this case, the best way to charge the battery is “idling”. If the alternator is not malfunctioning, the idling process will partially charge the battery. Alternatively, you can start it briefly to charge the battery.

It should be remembered that these methods will not charge the battery. You must use a multi-level battery charger to ensure that the battery is appropriately charged to the best capacity. 

charging of a battery

The Initial Charge Time Duration

The time required to charge the car battery depends on the time of the last charge. The time needed to charge the car battery by driving varies from vehicle to vehicle. Generally speaking, you must maintain an RPM (revolutions per minute) above 1000 for a specific time. The less charge in the battery, the more time it takes to charge.

Statistics indicate that when you are driving on a high-speed lane, it takes up to half an hour to charge the battery. On the other hand, when driving on a busy traffic lane in a city, the charging time may be extended by an hour or more. Remember not to use lights, radios, stereo systems, heaters, or any other electrical equipment while driving a car with the intention of battery recharge.

Read More: How to Hook Up Satellite TV in RV?

Some Frequently Asked Questions 

Can a Completely Dead Battery be Recharged?

Yes. It takes 4 to 24 hours to fully charge a completely dead car battery, depending on how many amperes the car battery needs to be charged and the size of the battery.

The most common rate for car battery chargers is about 4 amps. To fully charge a 52Ah battery, it takes about 10 hours from dead to full charge, but you may be able to start the car within 1 hour.

What Drains a Car Battery While it is Off?

When the car battery quickly discharges after you turn off the engine, it is usually caused by one of the following three reasons: Your battery may have reached the end of its life (usually 4 or 5 years); a parasitic drain is depleting the battery; or problems in the electrical system are affecting battery power.

Most battery problems can be diagnosed at home through visual inspection, digital multimeters or cheap hydrometers.

Does the Revving Engine Charge the Battery Faster?

If you reeve the engine faster, the battery will charge more quickly. Why? Because the faster the crankshaft rotates, the quicker it rotates the belt that runs the alternator.

The faster the alternator spins, the more electricity it generates, which can run all the electrical equipment in the car and charge the battery. It is also a great way to charge a car battery without a charger.

How Often Should I run My Car to Keep the Battery Charged?

Unless this is a high-end car equipped with a lot of power-consuming equipment and computers, the car should be able to park for at least a month without draining the battery.

Moreover, the battery will slowly lose its charge when it is idle, and starting the car will consume more power.

This is one of the reasons why you have to drive a few miles at intervals, so the battery has a chance to charge. If the car is parked for a month or more, the battery may lose too much power, so it needs a quick start-or charge it before the engine starts. Therefore, it is sufficient to start the engine at least twice a month. This step is also a great way to charge a car battery at home

Why Does My Car Battery Keep Dying Overnight?

The slow battery consumption, when everything is off, is called parasitic power loss. This happens when something (such as glove box lights, amplifiers, or any electronic components) should not get energy from the battery. Since the alternator does not generate electricity. The difficult part will be pulling out power from the battery. And draining it slowly overnight until your vehicle cannot start.

How Long Will the Car Battery Last Without an Alternator?

It all depends on the capacity of the car battery. If the battery is not fully charged, the vehicle may work for 5 to 30 minutes. If the battery is fully charged, the operating time will increase.

How do you Keep a Car Battery Charged When Not in Use?

The battery is a vital part of the vehicle. From starting the car to running all its accessories, the battery provides the power your vehicle needs to keep moving. Under normal driving conditions, your vehicle’s alternator will charge the battery while you are driving. However, if your car is not used for a long time, it may damage the battery. Moreover, if your battery has been used for three years or more, it may be fatal.

How long a car needs to sit before the battery is dead depends on the car. But any vehicle owner can take some steps to keep the battery healthy. Do review these tips to maximize your battery performance and keep it charged when not in use:

  • Start the vehicle and drive it for one day every few months. Not only will you charge the battery and evaporate the water vapor that has formed. But you will also exercise some of the moving parts in the car that should move occasionally. If the brake caliper and transmission solenoid valve are left for a long time, they may stick or rust. The belt will also dry out and crack.
  • The second suggestion is to buy a trickle charger. For less than $30, you can get a battery charger that can “trickle” a small amount of power to the battery as needed. The advantage of the trickle flow charger over traditional chargers is that it will never let the battery run out. So as long as you are willing to use it, you can start the car. The trickle flow charger does not require monitoring. You only need to connect it, plug it, and use the battery at any time.

Can you Leave a Car Battery Charger on Overnight?

If you use a high-quality charger, there would be no risk of overcharging. But the connection time between the battery and the charger should not exceed 24 hours. A full charge is usually obtained overnight, and some chargers as well enable at least partial reconditioning of the battery too.

What Causes a Car Battery to go Dead Suddenly?

There are many reasons for a car battery to go dead suddenly. This includes lack of battery maintenance (for example, not keeping the terminals clean); malfunctioning of the diode bridge or voltage regulator in the alternator; failure to charge the battery by the alternator when the car is running; or freezing of the battery when the temperature is too low.

Can you Fix a Dead Car Battery?

The most common way to fix a dead car battery is to jump-start it. To do this, all you need is a set of jumper cables and another car with a functional battery. Remember, if the car’s battery ruptures and leaks acid, never try to jump-start the car.

Final Words

In conclusion, despite its importance, you may not spend much time thinking about your car batteries. That is until the battery is dead.

Once the battery is dead, you can start your car by jump-starting it. But you’ll need more than that to fill it up again. Trust us, knowing how long it takes to charge a car battery is essential. And this has been thoroughly emphasized above. Learn more about battery charger here.

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