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How Long Does It Take to Charge a Car Battery while Driving


The last thing you want while driving somewhere in your car dying in the middle of nowhere. In most cases, not having enough charge causes this problem.

In a situation like this, you might wonder how long it takes to charge a car battery, how can you fix your car to keep going, or how to take care of your battery so that situations like this do not occur – all these questions will be answered here.

This detailed article will guide you through everything you need to know about the car battery and charging it—also, As some tips on how to keep your battery healthy.

How Long Does It Take to Charge a Car Battery

How long it takes to charge a car battery depends on two things, the charger and the car battery itself. Higher ampere chargers can provide fast charging, but a low ampere charger is better for the battery’s longevity.

You can use simple math to find out the exact time it takes to charge your car battery.

Charging Time of Battery = Battery mAh÷ Charging Current

However, to find out the charging current…

Charging Current  = Battery Ah x Efficiency Loss

  • The average accepted efficiency loss is 20% per hour.
  • While the newest batteries paired with quality battery chargers will be at a low 10% efficiency loss.
  • And if it is older than o2 years batteries have 20%-30% efficiency loss.
  • If you only know the CCA value of your car’s battery, You can divide the CCA by 7.25 to get Ah.

Below is some charger information about the time it takes to charge a car battery.

Here is a table that shows how much time a car needs to depend on CCA.

How Long Does It Take to Charge a Car Battery

Car battery capacity Car battery voltage Car charger Amp Required Charging TIme
50 Ah 12,01 – 12,10 V 5A 6 hours
50 Ah 12,01 – 12,10 V 12A 5 hours
100 Ah 12,01 – 12,10 V 10A 12 hours
150 Ah 12,01 – 12,10 V 15A 12 hours
200 Ah 12,01 – 12,10 V 20A 12 hours
250 Ah 12,01 – 12,10 V 25A 12 hours
250 Ah 12,01 – 12,10 V 40A 7.5 hour

40 amps Battery Charger

A 40 amps battery is useful if you want fast charging. It is very effective even when the battery is depleted. It only takes a few minutes to charge and start your car.

It comes in handy, especially when you are traveling. Moreover, you can carry it anywhere and want to charge real quick. You simply have to connect with the jumper cables, and you are good to go.

10 amps Battery Charger

10 amps battery can in a few hours. It can charge a small car’s half-discharged battery in about 2-3 hours, considering the small car battery is RC 40-60.

For a medium-sized battery, like RC 60-85, it takes about 3-4 hours to charge a half-discharged battery.

Approximately 4-7 hours is needed if you want to charge a large battery, such as RC 85-110. You need double the time mentioned if the battery is fully drained.

4 amps Battery Charger

A 4 amps battery is not suitable for you if you want fast charging. A deep cycle battery holds 48 amps, and with this charger, it takes almost 12 hours to charge.

However, it is ideal for small batteries. It works for less-used batteries and works like a trickle charger. It will switch off charging when it is complete and will start again if the battery drops.

2 amps Battery Charger

A 2 amps battery charger will take 24 hours to charge a 48amps battery. It can be used for slow charging like a trickle battery. If you own an antique car that you hardly drive, you can charge it with a 2 amps charger. It is best to use to maintain some charge in the battery.

How Long Does It Take to Charge A Car Battery

Types of Charger

Generally, there are three types of chargers for a car battery. A brief discussion of different types of chargers is given below.

Linear Charger

The linear charger is the simplest type of charger and the cheapest as well. You can charge your battery using the wall socket. Using a linear charger might be the simplest way but not the fastest.

This battery operates at low amperage. As a result, it takes quite some time to charge the battery. Generally, it takes about 12 hours to charge a moderate car battery.

The linear battery charges continuously. You need to manually disconnect the charger when charging is complete. If you do not disconnect in time, it can damage your battery. It can also explode if you overcharge it for too long.

Multi-Stage Charger

The multi-stage charger charges in burst instead of a linear stream. This method is better for battery cells. They are less prone to become damaged from a multi-stage charger.

It is also called an intelligent charger because it charges in bursts and has a higher ampere. It can be up to 50 amp. It takes very little time to fully charge a car battery; usually, it takes about an hour.

Trickle Charger

A trickle battery is ideal for you if you plan to keep your battery on charge for a long time. Mechanics use this charger as they keep the battery charging while working on other parts of the car. It is useful, mostly when the battery is detached. It keeps a battery in a stable state, so there will be no problem when you insert it into the car again.

A trickle charger charges the battery with 2 amps. Therefore it almost takes 48 hours to charge an average car. The best thing about the trickle charger is that it automatically stops when the battery is fully charged. So you do not have to worry about damaging the battery.

How Long Does It Take to Charge a Car Battery While Driving

The safest way to charge your car battery is by driving. The time needed to recharge a battery depends on the last time it was recharged.

While driving, the power from engines goes to the battery. There is no possibility of overcharging and damaging the battery. It charges the battery through an alternator until it is fully charged, and after that, power will distribute power to other features.

Charging through driving takes a lot less time to charge. Using an external charger takes more time to charge. You can start your car in 30 minutes. It takes nearly 1 hour to charge your battery while driving fully.

Revolutions per minute (RPM) of your engine determine the duration of your battery charging. You will need a minimum of 1000 RPM to generate enough extra power for your battery. Fast speed generates more RPM.

If you want to charge your battery while driving, you should drive on a highway or other long, open road where you can go at least 55 miles per hour. You can charge it at city speed too, but that might take a bit longer.

Charging a Dead Car Battery

Rarely you might face a situation where your car will not start. No matter what you do, it will not work. The battery is dead and you need to revive the dead battery.

You can use a charger to charge your battery. If you are in a hurry, you can use a 40 amps charger, or if you want stable charging, you can use a 2 amps charger. It takes about 4 to 24 hours for a car battery to get fully charged.

To determine how long it will take to fully charge your battery, you need to look at your battery’s ampere and your charger. If you have a 48 amp battery and a 4 amp charger, it will take almost 12 hours to fully charge your dead battery.

When your battery is dead, and you start charging, you can start the car after about 1 hour. If the charger does not work in any way, the only option you are left with is using a jump start.

A GEL/AGM battery will be charged faster than other wet batteries. You need to be cautious about fast charging with a higher amp. They can charge faster, but they can destroy your battery if you forget to disconnect it.

Jump-Starting a Car

If your car dies and you need a quick fix, you should consider jump-starting your car. Modern jump starters can start your car instantly. However, it is a short-term fix in case of an emergency.

Your car can die for two reasons, either the battery is dead or other damages affected the battery. After jump-starting you, the car can usually run for 10-15 minutes. However, you need to be careful about jump-starting your car, and doing it frequently can severely harm your vehicle.

Risks of Jump-Starting

Keep in mind that jump-starting your car can put stress on your alternator. The alternator is trying both to power the car and recharge the battery. This puts a lot of stress on the alternator. Therefore, your alternator can damage your already damaged battery.

Jump-starting can cause severe damage to your car. It might give you a solution in an emergency, but the impact on your car is not good in the long run. The cost of repairing your car after the damage can be a lot more than replacing a battery.

When you know for sure that your car battery is dead, jump-starting will not cause any problem. It cannot damage your battery anymore. So you can jump-start your car and take it to the mechanics. It would be best if you replaced the battery then.

However, you should not keep the damaged battery for long. Waiting can cost a lot for the repair. If you have a warranty for your car battery, then your cost can be covered.

Tips for Jump-Starting

Switch other electricity-consuming features in your car before jump-starting, like heated seats, rear heated screen, lights, wipers, etc. After jump-starting, leave it connected to the car and keep the engine running.

Before jump-starting, you need to connect the battery to the jumper of the donor car. Keep the donor car engine at approximately 3000 rpm for five to ten minutes. This way, your flat battery gets boosted and also does not stress the alternator.

You should drive your car at highway speed with all or most electric features turned off. Try to avoid jump starting at night as you will need to turn on the lights.

After 30 minutes of driving, your vehicle should be charged. If you face the same issue again, there is a possibility that your car has some different problems.


Charging Car Battery at Home

You don’t always have to charge your car in the mechanics’ workshop. It is not that difficult. All you need is one of the chargers mentioned above. It depends on your choice and your car’s battery what battery charger should be best for you.

If you want a faster charger, then you can go for a higher ampere charger and vice versa. However, lower ampere or trickle charger comes with the auto-stop feature. You need to manually disconnect the charger when charging is complete. Otherwise, you can destroy the battery of your car.

While charging at home, make sure you are connecting the charger accurately. Connect the receiver side to the power outlet and connect the battery to the output side. Do not forget to connect the plus to the plus sign and the minus sign to the minus.

If Nothing Works

If nothing works and your battery keeps draining, you should take your car to a mechanic. You must solve the problem of your battery draining.

Even if you insert a new battery, the same problem can occur. Therefore, you must solve this problem. There can be a problem in the electrical connection, which can cause the problem, not your battery.

If the problem is in your battery, then you can replace your car battery. Most mechanics nowadays have tools to identify how much battery life is remaining. From that, you can understand the condition of your battery and the step you should take next.

Tips for Keeping Your Battery Healthy

Charging the battery is the key to having a healthy battery. You should not let your battery sit for a long time without using or charging. It can harm your battery. There are a few things you can maintain to have your battery in good or working condition.

Do not keep your car in extreme weather. The temperature can damage your car’s battery life. Best to keep your car in your garage. Do not leave your car is too hot or too cold weather.

Before leaving the car, double-check if you turned off ac, radio, or other devices that can drain your battery charge very fast.

You should keep your battery terminals clean. Make sure it does not get rusty. Rust can hamper electricity flow to the engine resulting in a problem with your battery. It does not take much to keep the terminals clean. You need to do that every six to eight months.

  • Tightly put your battery in place. Otherwise, it can vibrate with damages internally.
  • Check the voltage every time you put oil in your car.
  • Do not leave your car’s devices running if it is idle.
  • Every part is interconnected. Make sure everything else is also working with the battery. Other damaged parts can take a toll on your battery.
  • Short rides hamper battery life. If possible, limit shot rides.


A car battery is a low maintenance thing, and you hardly notice any problem with it. If you drive your car regularly, there is a high possibility that you will not face any problem with your battery.

Regular driving is sufficient to keep your car battery charged. If you let your car sit for long, there could be some battery-related problems in that case.

However, you should check your car battery and clean it every once in a while. It does not take much effort to do so. Now that you have a good idea about charging car batteries and how long does it take to charge a car battery.

Hopefully, there will be no problem regarding this issue. It is best to prevent the problem before it occurs.