How Long Does It Take to Charge a Car Battery?

In times when the vehicle is stationary for a long time, the battery can be discharged and even seriously damaged. To avoid this, there are car battery chargers. You only need a plug and your battery will be recovering charge as if it were a cell phone.

The problem with these devices is that there are many models and not all of them are suitable for every situation.

If your vehicle battery is dead, you need to know how long it will take to fully charge. A dead vehicle battery typically takes 4 to 11 hours to charge with a 10 amp charger.

If you use a 2 amp charger, it can take 2 to 4 days to fully charge the battery. It is not necessary to fully charge the car battery for it to work. You can charge it enough to make it work.

Car Battery Drained – The causes

A battery is discharged by supplying electrical energy to the car’s engine and electrical consumers and is recharged through the running alternator.

Short circuit in the electrical system

When a short circuit occurs, a large amount of current is drawn from the battery in a short period of time and converted to heat.

Leaving vehicle lights on

Car lights consume a lot of power and should be turned off while the vehicle is parked.

Auxiliary heating

If the auxiliary heating is not turned off, the battery will be completely drained. This can also occur if the battery is too small.

Alternator failure

If the alternator does not charge the battery while driving, the control units and other electrical equipment will be powered only from the battery until the battery is completely drained.

Alternator regulator failure

If the alternator regulator fails, a total drain will occur as a result of insufficient battery charging or overcharging.

Failure of a control unit

If the control units are not switched off when the engine is shut down, the battery will be completely discharged.

Installation of electrical equipment

Additional electrical equipment, such as the seat heating system, often draws power from the cigarette lighter connection, causing the battery to discharge quickly.

Using the wrong battery

To avoid reducing the service life of a defective battery, it should always be replaced with another of the same type.

Short journeys

On short journeys, the amount of electricity used exceeds the capacity of the alternator. It is, therefore, better not to use superfluous equipment (seat heater, radio, etc.).

Radio, television, and DVD

Radios, GPS systems, and other entertainment devices consume a lot of energy and drain the battery completely if they are not properly recharged.

How Long Does It Take to Charge a Car Battery

How Long Does It Take to Charge a Car Battery?

It takes 4 to 11 hours to fully charge the car battery with a 10 amp charger. If you use a 2 amp charger, it will take 2 to 4 days to charge the battery.

Please note that if any charging method fails, the battery may be damaged and will need to be replaced.

2 Amp Charger

A 2 amp charger is appropriate if you want to connect the car to the charger for a long period of time. With a 2 amp charger, it can take 24 hours to 2 days to fully charge the car battery.

4 Amp Charger

It will take about 12 hours to fully charge the vehicle battery if it is charged with a 4 amp charger. Consequently, if you need a fast charger, a 4 amp charger is not an option. This charger, on the other hand, is ideal for smaller batteries.

6 Amp Charger

The correct answer is 9 hours. Based on a 54 amp capacity battery at a 100% discharge rate.

8 Amp Charger

In 3 to 4 hours, an 8-amp charger can charge a battery that is 50% discharged. If the battery is fully discharged, multiply these times by two; if it is not fully charged, multiply these times by two.

10 Amp Charger

If you use a battery charger, it will take 4 to 11 hours to fully charge the battery with a 10 amp charger.

15 Amp Charger

A 15 amp charger can charge a small car battery that is 50% discharged in about 2 hours, a medium-size battery in about 2.5 hours, and a large vehicle battery in about 2.5 hours.

20 Amp Charger

A semi-discharged small car battery can be charged in 1.5 hours, a medium-size battery in 2 hours, and a large vehicle battery in 2 hours using a 20 amp charger.

The number of times will double if the battery is fully discharged. It is not a good idea to use such a large charger.

30 Amp Charger

A 30 amp charger can charge a 50% discharged small vehicle battery in about 1 hour.

40 Amp Charger

At 40 amps, the charging time of a car battery should not exceed 2 hours. Fast charging car batteries is dangerous and should be avoided at all costs.

50 Amp Charger

A partially depleted battery can be charged in 45 minutes with a 50 amp charger. For vehicle batteries, do not use such a large charger.

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

The alternator is responsible for charging your car’s battery. The battery will charge faster if you keep the engine revolutions high.

If you are traveling on the highway, you should be able to charge your vehicle’s battery in 30 minutes. If you are driving in the city, it may take an hour or more.

How Long Does It Take for a Car Battery to Charge with a Trickle Charger

How Long Does It Take for a Car Battery to Charge with a Trickle Charger?

Trickle charging is a common method used by owners and drivers of motorcycles, off-road vehicles, and recreational vehicles (RV).

The operating current of the slow charger is approximately 2 amps, so it takes 24 to 48 hours to charge a 12-volt automotive battery.

How Long Does It Take to Charge a Dead Car Battery

Charging a dead vehicle battery takes at least 4 hours and can take up to 24 hours, depending on the power of the charger and the size of the battery.

The good news is that it is not necessary to fully charge the battery before you can start the vehicle. In an emergency, charge it for about 1 hour with a regular charger to get adequate power.

What to Keep in Mind When Buying a Car Battery Charger

There are many features that distinguish one charger from another. Below, we will go over each of them, with the understanding that this is where you can compare battery chargers on the market.

Output power of the charger

You should choose a charger with the same power output as your battery. You should look for the number that corresponds to the Amperes per Hour (Ah), which will appear on your battery. The charger you buy should have the same amount of Ah.

Battery type

You should know the type of battery your vehicle uses, as there are many different types, such as lithium batteries, calcium-alloy batteries, wet cell batteries, lead-acid batteries, gel batteries, AGM batteries, and many more. To purchase a suitable charger, you must first determine the condition of your car battery.


There are 6 V and 12 V chargers. The latter are the most common in the latest versions and also the best, as they charge the battery in less time.

Capacity to serve as starter

Batteries that rely on high amperage are often used to jump-start the battery when it is nearing the end of its useful life. When we buy one with these characteristics, we are acquiring a “two-in-one”: battery and jump starter.


Although it does not greatly influence its main function, having a battery charger that we can store or carry anywhere will be much more convenient. Older versions are very robust and large, while modern versions are usually much smaller.

Consider all these factors before buying the most suitable charger for your situation.

How To Connect A Car Battery Charger

Connect the positive (+) cable from the charger to the positive terminal of the battery, which is usually red. Connect the negative (-) cable, which is usually black, to the negative terminal. Connect the charger to the power outlet (if necessary) and turn it on. The indicator light (ammeter) will illuminate to show that the battery is charging properly.

How to Use a Car Battery Charger

Although the numerous applications and features of many battery chargers today may make their operation more complex, the basic procedure for setting up a vehicle battery charger is generally the same:

  1. Remove the negative battery cable from the negative terminal first, followed by the positive battery cable from the positive terminal.
  2. Check that your charger is not plugged into an electrical outlet and that the power switch (if present) is turned off.
  3. Connect the charging cable to the positive terminal.
  4. Connect the negative cable of the charger to the corresponding connector.
  5. Turn on the charger and choose the appropriate setting (if applicable).
  6. During the charging process, regularly check the charger to verify that there are no problems.
  7. While the charger is in operation, do not touch or move any of the charging cables.
  8. Before removing the charging cables from the battery charger, switch off and disconnect the charger.
  9. First, disconnect the negative charging cable.
  10. Remove the positive charging cable.
  11. Reconnect the positive battery cable.
  12. Connect the negative battery cable once again.

Final Thoughts – How to Charge a Car Battery

A 10-amp charger takes between 4 and 11 hours to charge a depleted vehicle battery. The trickle charger is the most recommended of the three chargers, as it prevents overcharging the vehicle’s battery. If you use a 2 amp charger, it will take 2 to 4 days to fully charge your vehicle’s battery.


Hi, I'm the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that's why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.