By Erik Watkins

How Long Does It Take To Charge A Car Battery? (4-20 Amps)

Last updated: May 11, 2023
How Long Does It Take To Charge A Car Battery

We will provide the right answers to these questions in this article. Knowing the exact time you need to charge your car battery can prolong its useful life. Don’t worry if your battery is depleted during your trip or business.

How Long Does It Take To Charge A Car Battery?

The time for charging a dead car battery will depend on the charger’s power demand and the type of battery. You can spend about 2-4 hours making a full charge for a 20 Amp car battery.  But the required time can be up to 12 – 24 hours if your battery is 4 Amp, the most popular type of automotive battery.  

It can take about 10 hours to recover a 52 Ah battery from dead state to be fully charged to allow you to start your vehicle in under an hour. 

Consider your automobile battery charger to determine how much amps it produces. High amps will charge your vehicle’s battery faster. Low amperage is more effective for long-term battery charging maintenance.

You also check the type and size of your vehicle’s battery. A medium-sized vehicle often uses a battery with a capacity of 40-80Ah. GEL or AGM batteries have a faster charging time than common wet types.

What Is A Good Speed To Charge A Car Battery?

What Is A Good Speed To Charge A Car Battery

The speed suitable for charging your automobile battery should meet what you need. Charging the battery fast can harm it such as shortening its lifespan. If you make a long charge at low amps, it is useful to increase the battery’s life. 

A common car battery charger outputs 4-15 amps. It takes 24 hours to fully charge such a dead battery for good charging maintenance. Inspect your automobile charging system regardless of charging speed settings to use them properly with your demands.

It is the safest and fastest to charge your battery at a speed of 8-15 amps without ruining it. If you charge it faster than 15 amps, you risk damaging it and shortening its lifespan.

How Long To Recharge Car Battery At 40 Amps?

The 40 amps charger is an effective and quick choice if you want to give your vehicle a complete charge. Despite your completely dead battery, you only connect to the 40 amps charger and wait for a few minutes for your car to restart. 

When you travel or go far away from your home, this unit is beneficial to recover your drained battery quickly. After your battery gets a full charge, you can jump start it with jumper wires

You should choose the smart charger that can automatically switch into a trickle by reducing the battery by 40 amps to protect your battery from damage.

How Long Does It Take To Charge A Car Battery At 4 Amps?

Because a deep cycle battery has a capacity of 48 amps, it takes 48 hours to charge it at 1 amp. If you want to charge your automobile battery at 4 amps, you need up to 12 hours to complete the charging process. A 4 amps charger is not a decent choice to make a fast charge. Instead, it is suitable for smaller types of batteries. 

Consider a smart 4 amps charger in case you need to keep your car battery on low amperage or maintain it for a longer time. This charger acts as a trickle charger to recover the less-used batteries and turns off when fully charged to protect your battery.

See more: How Many Volts Does A Car Battery Need To Start?

How Long Does It Take To Charge A Car Battery At 2 Amps?

With a 2 amps charger, charging your automobile battery to an adequate level will take 24 hours. This time is proper to give a 48 amps battery a complete charge. Thus, this type of charge plays a role as a trickle charger to keep your battery at a sustaining level rather than trying to get a fast charge to restart it.

2 amps are ideal for applying to antique vehicles when you want to leave your battery attached to the charger for a long time for driving a while. The smart 2 amps charger is the best choice for maintaining a consistent charge in the battery and keeping your car in a ready state for driving. 

How Long To Charge A Car Battery While Driving? 

While driving, you should charge your battery within 30 minutes and about 1 hour on city streets. Driving your car around for at least 30 minutes after starting to obtain a perfect charge. 

If you don’t drive, you can use a battery charge to save time. It is convenient and beneficial to charge your dead battery for a fast recovery. 

How Can You Know A Car Battery Needs A Replacement?

The lifespan of a vehicle battery is from three to five years. When it is about to die, you should check its signs for a timely replacement. 

Because aged vehicle batteries are difficult to retain a charge and fail to start your vehicle, it also tells you about replacement. Another indicator is that you have to jump start your vehicle regularly.

Which Type Of Car Battery Charger Is Best To Charge?

You must choose which kind of battery charger you require: a maintenance charger or a quick charger? Modern chargers are simple to set up with battery charging checking, which regulates the amps. However, before purchasing one, test how many amps it charges with.

Inexpensive chargers claim to deliver more amps than they can provide. It is preferable to use a high-quality charger with lower amps. It will extend the lifespan of your car battery and reduce the danger to your automobile.

How Many Volts Does A Vehicle Battery Need To Be Fully Charged?

A 12-volt battery with 6 cells comprising 2.1 volts of electricity is necessary for your vehicle battery to get a complete charge. A car battery can be fully charged at 12.4 to 12.6 volts when turning off the engine.

When the voltage of your battery lowers, it significantly impacts its overall performance. A voltage of 12.1 volts indicates your battery charge finished only 50%. The battery is depleted if it lowers to 11.6 volts.


Hopefully, you can know the answer, and you will solve this trouble the next time. Don’t turn on your vehicle’s electrical units when not in use. Besides, to avoid battery drain, keep your vehicle on the move from time to time.

Automotive Mechanic at PowerAll

With 7 years experience in management positions leading automotive mechanics at PowerAll, Erik Watkins wishes to share useful knowledge and information about automotive mechanical equipment.


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