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How Long Does It Take To Charge A Car Battery?

There are different types of car batteries, ranging from small to large sizes. Depending on storage capacity or amp rating, this will determine how long it needs to charge your car batteries thoroughly. If you have an exhausted battery, how long might it take to fully recharge? We've researched this for you. 

A regularly sized vehicle's battery needs to be charged at 400 amps and at least 1,000 amps for a larger-sized car. Generally, a normal size battery that uses a 2 amp charger would take up to 24 hours to recharge, while using a 4 amp charger would take 12 hours. If you are using a 10 amp charger, it would only take 4 to 5 hours. But this doesn’t apply to larger size batteries, only to average-sized ones.

So, to sum it up, it will take 24 hours to charge a normal size battery using a 2 amp charger, but it still depends on how big your car battery is or the charger being used. It can also be determined in the car voltage to know if your car batteries are fully charged. Keep on reading to know the full details on how to fully charge a car battery.

Alligator clips clamped on the batteries, How Long Does It Take To Charge A Car Battery?

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Different Ways You Can Charge Your Car Battery

As mentioned above, there are many factors to consider depending on what variation it is, or how big your car battery is.

Charging A Normal Size Battery/Normal Size Vehicle

A small vehicle that consists of small batteries has around 40 amps per hour. If you decide to use a 2 amp charger, it would take up to 24 to 48 hours to fully charge the batteries.

It is also determined by the charger’s output. The higher the output, the faster a flat battery is recharged. For example, a 4 amp charger would take 12 to 24 hours to fully charge the battery. It is far less than the 2 amp charger, which takes 24 to 48 hours to fully charge.

Using a 10 amp charger would only take 3 to 6 hours to recharge, but experts advise that it is reasonable to only use a 2 amp to 8 amp charger for safety purposes. 

Charging A Medium-sized Car Battery/Medium-size Vehicle 

Screwing in car main power line to the battery

In mid-sized batteries that are around 50 amp per hour, the charging time using a 2 amp charger is up to 31 hours, 5 to 6 hours at 6 amps, and 3 to 4 hours at 8 amps

A car battery's general size or normal size comes with a 48 amps battery. It means that in a 1 ampere, the charging time takes up to 1 hour to be charged. This is how you can calculate the charging time.   

Charging A Large-sized Car Battery/Large Sized Vehicle

In larger sizes, car batteries that have 75 amps per hour can be charged up to 50 hours at two amps and 10 hours at 10 amps.

Charging A Car Battery Using A Trickle Charger

A trickle charger uses a small amount of electric current, it is typically 1.5 or 2 amperes.

The purpose of using a trickle charger in your car battery is to leave it charging in your car for an extended time without damaging your car batteries. Trickle chargers have a self-discharge component that uses electricity to refill the batteries. It takes up to 48 hours to fully charge your car battery.

 There are also advantages to using a trickle charger:

  •   Prevents battery failure.
  •   Money saver, since it doesn’t run out of energy easily.
  •   It helps to extend the battery’s life.
  •   Improves the car battery’s health on a long-term basis and also reduces the risk of overcharging.

Does idling the car charge the battery?

Definitely yes! Car batteries will charge slowly, even at idle. An alternator supplies the battery's main power source. It transforms the automated energy of the car’s engine into electrical energy and transmits it to the battery to be charged.

How do I know if my car battery is fully charged?

Car mechanic clipping a car battery

Several procedures can be applied, depending on your liking. 

  • Using an ammeter: A tool or instrument used to measure electric current in amperes. It is to check the battery’s rotational charge and to confirm if your battery’s storage is sufficient.
  • Using a car battery voltage: The engine starting point is at 10 volts (v); this is equivalent to 0% charged. To know the battery's charge percentage, its reading begins at 10v (0 or empty), and corresponds to the highest 15v (fully charged or topped up).

For example: 12.6+v = 100% or normal (fully charged). See below for attitional voltage rates to indicate battery charge percentage: 

  •    12.5v = 90%
  •    12.4v = 80%
  •    12.3v = 70% Weakness
  •   12.2v = 60%
  •    12.1v = 50% Slow cranking
  •    11.9v = 40% No cranking
  •    11.8v = 30%
  •    11.6v = 20%
  •    11.3v = 10%
  •    10.5v = 0% Dead

How often should I start my car to keep the battery charged?

Charging car battery using alligator clips

If you’re not using your vehicle frequently, start up your engine at least every 2-3 weeks. Because if it’s idle for some time, the battery itself runs down, so to avoid this circumstance, leave the engine running for at least 10-15 minutes so that the electric power generator refills its fluids. It will give you the assurance that the car itself is running and working just perfectly fine.

How long can a car battery last without driving?

In general, car batteries that are in good condition typically last for at least two weeks. Even if it’s idle, it is not required to be recharged right away.

How do I charge my car battery at home?

It is necessary to have the right tools for this course of action. This is to avoid being electrocuted, as this would result if your car battery still has juice in it. The right tools will be of help, especially since in different circumstances some batteries are inaccessible, and some are under the vehicle's fender.

Steps In Charging Car Battery At Home

Preparing to charge the battery:

  • Double-check if the charger is off. Make sure that you are using the right gear.
  • Determine what kind of battery you have. Inspect where the battery was manufactured to learn its battery voltage. 
  • Get the appropriate car charger for your vehicle. Generally, most car chargers work with all types of batteries. But there are exceptions like gel cell batteries.
  • Detach the battery from your car. This step is important to ensure the battery’s health is still in good condition so you can decide if it needs a cleaning or maintenance. Check the user manual if you are unfamiliar with the battery's location. Disconnect the negative terminal first, then the positive when removing a battery.
  • Lastly is to clean your battery terminals, even a small scale of dirt would affect the charging cables to function decently. Be careful with the terminals if you see white powder in them this indicates that it has dried sulfuric acid in it.

The easiest way to charge a car battery at home step by step:

  •   For safety purposes, make sure that the charger is turned off when connecting.
  •   Hook up the positive red cable on the charger to the positive terminal on the battery.
  •   Hook up the negative black cable on the charger to the negative terminal on the battery.
  •   Set the charger to the slowest charging rate.
  •   Turn on the charger and set the timer.

Conclusion

Alligator clips clamped on the batteries

So how long does it take to charge the car battery? The answer is, in general, it would take at least 24 to 48 hours to fully charge a car battery with a 2 amp charger.

For even more great information on keeping your car battery in top condition, check out our related posts: 

How Long To Charge A Car Battery With Jumper Cables?

What Happens When Car Battery Dies?