How Long Does It Take To Charge A Car Battery?

Most internal combustion engine (gas-powered) cars run on a 12-volt battery system. The battery holds a charge for a few days to a few weeks.

It keeps a charge so it can give the motor enough power to start. Then the motor turns the alternator, which in turn charges the battery. But what happens if the battery drains and you can’t start your car?

How Long Does It Take To Charge A Car Battery?

1 hour – 24 hours. It requires a minimum of 1 hour to get the car running and 24 hours to completely charge it.

How long it takes to charge a car’s battery is not a question with only one simple answer. Oh no, sir. There are many types of car battery chargers out there. Many have varying amperage ratings i.e. how fast they can charge.


The higher the amperage, the faster the battery can charge. Likewise, it takes longer to charge if the value of the amps rating of the charger is small, say 2-4 amps. The size of your car battery will play a factor in affecting the time it takes to charge.

On larger vehicles, it may take double or triple the amount. If you have a Geo metro, you could be up and running before your latte is finished! So which should you choose? Is there one single best charger that blows all others away?

Well, the answer is… it depends. What do you need it for? What type of vehicle do you have? Do you want it ready in minutes or hours?

These factors vary from vehicle to vehicle and person to person. If you are in a hurry you may be looking for a 40A charger. If you don’t mind spending the night you can use a 2A charger. There are pros and cons to both. And we will discuss both below.

There are three basic car battery chargers:

  • 2 amp
  • 4-6 amps
  • 10 or more (a lot more) amps

How Long Does It Take To Charge A Car Battery With 2 Amp Charger

The 2A charger is the slowest charger. It is good for reviving an old battery, or one that has not been used in a while and needs a little help coming back to life.

These can also be used for battery maintenance. This slow and steady charge will do little damage to the battery. People often use these chargers for overnight top-offs. Use them when you are not ready to replace your battery yet and you want to maximize its life.

best 2 amp car battery charger

Maybe you have an electric lawnmower and the battery needs a little boost. A couple of hours with a 2 amp car charger and it should be ready to cut grass.

This is the slowest and safest type of charging. If you need something similar but you aren’t as patient you could opt for a 4 amp battery charger.

A normal 12-volt battery will need about 12-24 hours to charge from completely dead.

Charging The Battery Of Your Car With A Four Amp Charger

The 4A charger is more powerful than the 2A but it still is more of a trickle charger or maintainer than a “get up and go” type. This one will get you going in a few hours rather than needing all night like a 2A.

Damage is minimal with this charger as well as charging is a more natural chemical reaction.

Think of this type of battery charger that will charge your motorcycle before that ride this Sunday morning. Or you have to charge your battery at work so you can drive home later in the day with no issues.

A normal 12-volt battery will need about 12 hours to charge from 0% to 100%.

Charging The Battery Of Your Car With A 40 Amp Charger

Then you have higher amperage types. They range from ~15 amps and up. Some auto shops even have 200 amp starting capabilities. They will charge your battery in minutes or hour(s).

Some even have the function to jump-start a car if that is all the battery needs. This type of consistent charging can limit the life of your battery. Do it only when you need it or you are in a rush.

You can charge a battery in about an hour with a 40 amp charger.

If you get a 40 amp charger make sure it is a smart charger. Some older chargers do not have an auto shut off feature that can If the charger keeps charging the battery when it is charged you may end up damaging or even ruin a Spending a little more for a smart charger with “auto shut off” can save you hundreds of dollars over the course of its life

Is Fast-Charging Suitable For Your Car’s Battery: A Comparison Between Fast And Slow Charging

Now that you are aware of all the types of car battery chargers, it is important to discuss which ones to use under what circumstances and also the pros and cons of both and how it may affect the life of the battery of the car or the vehicle.

If the electrical system is in good condition it may only take a few minutes for a newer car to get enough juice to turn over. If you can get your car to turn on, then the alternator can charge the car itself and the battery charger is not needed.

driving your car is charging your car. That is how the car works. You store enough energy in your battery to turn on your car with the twist of a key or the push of a button.

Then your alternator keeps the battery charged enough to continue operation. It is a great and very effective closed cycle that works almost 100% of the time.

So if you can hear your car trying to start, doing that “chugga chugga” motion, and then clicks instead, the battery needs a little boost. You can throw any charger on it. It should not take the complete charging time to turn over.

Sometimes, it can only take 15 minutes. Then you can turn it over and drive off. But make sure you drive your car for a long enough time where your alternator can charge your battery. If not when you go to turn it on again, the battery won’t have enough juice to turn on.

Weather can affect the charging time. A cold battery is more sluggish. If you can see your breath it may be best to double any charging time. Residents of the colder states often have battery heaters for starting their cars in extreme climates

Short on time? Use a fast charger.electric portable car battery jump starter

If you are in a hurry a 40A charger is what you want. Going one step further there are portable battery starters. They are about half the size of a car battery and can easily be stored in your trunk.

These things can jump-start your car a few times before needing to be recharged. They are perfect for jumping a car when you are alone or in an isolated area you want to get the hell out of quickly. They can also help others out in a pinch.

If you have more flexibility a 40A charger is great. It will charge your car quickly if you are alone and close to a power outlet. You can also monitor the charge so it won’t overcharge. 40A chargers also slow the charge as the battery nears full so you can try starting your car when the charge drops.

This is absolutely not a long-term solution, though. Continually charging your battery with a 40A charger will shorten the life of your battery. They should be used for used monthly or yearly. They are great for convenience. But if they kill a battery with repeated use the inconvenience of replacing a battery after a year instead of 3-10 years offsets this initial convenience.

Each type of charger has its advantages and they each come with their own disadvantages. Unfortunately, there is no one perfect solution. The tradeoffs are time, battery degradation, and convenience. You must choose what you desire most and what you can put up with.

Ideally, a new battery won’t have these issues. But life comes with obstacles. Forgetting to turn off your headlights, or blasting the A/C with the car off can lead to a dead battery. Having a backup can be a really good idea for you or for a neighbor.


Does Revving The Engine Charge The Battery?

Yes. By reviving the engine, the alternator increases its power output, sending more juice to the battery quicker. Some cars have an electronically set start-up procedure where the engine has a higher rev setting and slowly lowers as the engine warms up. This is used for more than charging but it is one reason.

How Long To Run Car After Jumping Battery?

When you get your car to start, let it run for a few minutes to furth the battery. Driving the car will increase RPMs and that will charge the battery quicker.

Battery jumper connecting order

Remove the jumper cable clamps in the reverse order:

  1. Black (negative) clamp from dead battery car
  2. Black (negative) clamp from the good battery
  3. Red (positive) clamp from the good battery (Don’t touch any bare metal from the car or you may get shocked!)
  4. Red (positive) clamp from the dead battery car.

Again, before you turn off your car again, be sure to drive the car for about 30 minutes to allow the battery to charge enough to start. Otherwise, there may be another jumpstart you need.

How Long Does A Car Have To Jump?

If it won’t jump the first time let both cars sit with the cable connected for 5-10 minutes. Then try again. It still won’t start? Try revving the engine of the car with the GOOD battery. This will maximize the power going to the dead battery. If you can’t start your car after 4-5 times you may risk damaging your car battery if you continue.

So, how long does it take to charge a car battery? The answer is clear! It depends! But it depends on you. We each have unique demands and they will influence which charger we need.

A charger should be a backup and replacing your battery will lessen or eliminate the need for a car battery. But backups are handy and they can help other people as well. It is usually better to have one and not need it rather than need a battery charger and not have one.

Thanks for reading and stay dirty.

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