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How Long Does It Take To Charge A Car Battery? Here’s The Answer

How Long Does It Take To Charge A Car Battery? Here’s The Answer

Inside your car, there is one component whose working is crucial for the other components to work efficiently.

And that key component is your car battery. It powers the engine, radio, infotainment system, headlights, taillights, and every other thing fitted inside your car.

However, a battery requires a specific voltage or charge to do all of this. You can assume a car battery is the same as your smartphone.

Just like the phone’s battery drains out after continuous usage, and you have to charge it up. Similarly, your car battery keeps discharging and will require charging.

Now, when you’re driving, the car’s alternator is responsible for charging the battery. However, in situations where the alternator isn’t working to its capacity, you’ll have to consider other charging options too.

But what are the options? How long does it take to charge a car battery? What determines a battery’s charging time? Can a fast charger be worth buying? Read on to find answers to all these queries here.

How Long Does It Take To Charge A Car Battery?

As said above, if the alternator is in bad shape and unable to charge the battery at a decent rate, the battery will lose its charge much faster than it’ll gain.

As a result, you will have to look up other options for charging the same. There are multiple ways to do so, but the most common is using a portable car battery charger.

If you use a typical portable battery charger of standard capacity, your car battery can charge in around 10-24 hours. But remember that the actual time of charging will solely depend upon the various factors discussed below.


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Factors that can affect the time of charging your car battery

Many factors determine how long it will take for your car battery to charge up fully. These are:

Amps in your battery

Here, I’m not talking about the CCA (cold cramping amps) but the number of amps your battery can deliver without charging.

Most car batteries have 48 amps. Yes, your car won’t use an amp/hour principle, but it will make it easier to understand the battery’s charging time.

It is because the battery charger manufacturers make chargers in the same way. Hence, say your charger has a rating of 1-amp, and your battery has zero charges at the moment, i.e., 0 amps.

Now, the 1-amp charger will take 1 hour to charge the battery with 1-amp, i.e., 48-hours to fully charge the battery. It is very slow.

So, you can use a 2-amp charger which will take around 24-hours, and so on. Hence, the more the charger’s amp rating, the less time it takes to charge the battery.

But, the battery condition is very critical here. If the battery is in a poor state, you might need to connect the battery to the charger for even more time.

Is your battery completely dead?

If you are dealing with a dead battery, remember that every battery’s construction isn’t equal. That is, two different batteries with different volts will take different times to charge.

To justify this, a battery with 2 volts left will take longer to complete than the battery having 10 volts.

The volts will not inform you about the amps left in the battery but is the easiest way to do so.

However, don’t just depend upon the headlights to discern whether the battery is low on volts or not, as the headlights may illuminate with the same intensity whether there are fewer or more volts. Instead, use a voltmeter.

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How much voltage is there?

You must know that voltage and amps are directly proportional. Thus, if there is less voltage, the battery may have fewer amps.

And you’ll need to charge the battery. The time required here will depend upon how much voltage/amps are there in the battery.

Type of charger

Above all the factors, the type of car battery charger you intend to use will significantly say the charging time. There are mainly four types of charger most people use, and these are:

40-amps charger:

As I said in the beginning, if the charger has a rating of 1-amp, it’ll take 48-hours to charge a battery having 48-amps in total.

So, you can assume how fast a 40-amps charger can work. However, there are a few risks of using such a heavy charger.

First, if you forget to shut off the charger on time, it’ll transfer excessive charge (amps), which can ruin your battery life. In rare cases, too many amps can result in a battery explosion.

Trickle charger:

A trickle charger is your typical battery charger available in 1-amp or 2-amp.

Again, using the former trickle charger will take as much as 48-hours to charge the battery against half the time of that of the latter, i.e., 2-amp.

Though both will take 24/48 hours to charge the battery fully, car experts feel that slow charging is better than quickly charging it.

Smart chargers:

Today, you also have the option to purchase smart battery chargers. As their name suggests, these chargers can sense how much battery is charged and adjust the charging speed, i.e., their output accordingly.

So, you don’t have to worry about over or undercharging your battery.

Furthermore, smart chargers are available in both 40-amps and trickle chargers. A smart charger can also be available as a fast, smart charger.

Multi-stage charger:

A multi-stage charger charges the battery in multiple stages instead of charging it in a single go. This way, even frequent charging doesn’t affect the battery’s performance and life.

A few factors determine how long it will take to charge the car battery fully.

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How Long Does It Take To Charge A Car Battery With A 12-Volt Charger?

A standard car battery usually holds 48-amps, which indicates its charging time. Besides, the voltage of the charger is equally important to consider here.

For example, a 12-volt charger will take approximately 12-hours to charge a battery fully. For just starting the car, charging a few hours, say 3-4 hours is enough.

How Long Does It Take To Jump Start A Car Battery?

Jump starting a battery or, in other terms, boosting a car battery is a standard process of instilling life in a fully discharged or dead battery by connecting it to another power source or car.

It’s a time-consuming process and not ideal if you don’t know about the same.

Still, it would help if you remembered that about 5-10 minutes are enough to jump-start a car battery. To fully charge, it will take 30-45 minutes.

Are Fast Chargers Worth It?

If you know what a fast charger means for a gadget, you can assume the fast charger for car batteries the same way.

But here’s a catch. There are two types of fast battery chargers: the usual fast charger and the smart, fast charger.

If you are using the former one, you will have to watch the charger to avoid overcharging the battery.

While in the second one, the smart charger will sense the battery charge and adjust its output accordingly. Hence, fast chargers are worth it only if they are smart chargers.

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How long to charge a car battery at 40 amps?

A 40-amps car battery charger will take just 2-hours to charge a battery fully. However, it’s not an excellent way to resort to it.

The 40-amps charger can ruin the battery life by overcharging it and, thus, use such a high-capacity charger in short bursts.

How Long To Charge A Car Battery At four amps?

Since a battery typically holds 48-hours, a four-amp battery will take around 12-hours to charge a car battery.

However, this period will fluctuate depending on factors like the type of charger, battery condition, and much more.

How Long To Charge A Car Battery At 2 Amps?

If you are using a 2-amps charger, you would need to spend at least 24-hours to charge a car battery having 48-amps.

How Long Does It Take To Charge A Car Battery With A Trickle Charger?

A trickle charger is the most commonly used car battery charger that’s economical and portable.

It’s available in 2 ratings: 1-amp and 2-amps. While the former will take 48-hours, the latter will take a full day to charge a car battery completely.

How Long Does It Take To Charge A Car Battery While Driving?

The battery keeps charging while you’re driving. But it depends upon the following factors.

The usage cycle

There are chances of you leaving the car sitting for long periods. It is a common reason why batteries lose their charge and become dead. If this is the case, it will take more time to charge the battery.

In such situations, you can jump-start the car’s battery or go for a short trip, or idling is also a possibility here.

But remember that none of the above methods will charge the battery to its total capacity. You’ll either have to use an external charger or drive for a decent time to do so.

Your driving speeds

Driving on high-speed lanes will take only half an hour to charge the car battery against more time it will take if you’re driving slowly in bumper-to-bumper traffic.

How much charge is present in the battery?

If there are zero charges in the battery for any reason, it will take more time to charge the battery. On the other hand, if there is still some charge, the overall charging time will decrease.

Hence, these factors govern how long it will take to charge the battery while driving.


This article talked about how long it takes to charge the battery, what factors come into play here, etc. These factors include the battery’s condition, i.e., whether it’s new/old, dead or not, the type of charger, battery voltage, etc.

You have multiple chargers available for charging purposes like fast chargers, 40-amp chargers, smart chargers, multi-stage chargers, etc. Using a smart or multi-stage charger is the best option due to its advantages. So, I hope to have cleared all your doubts regarding charging a car battery.