Home / Car Battery / How Long Does It Take To Charge A Car Battery? [2023 SOLVED]

How Long Does It Take To Charge A Car Battery? [2023 SOLVED]


There are several variables to consider. Size of the battery, the car battery charger being used, and do you need the battery fully charged or just enough to be able to start your engine. So, how long does it take to charge a car battery?

Typically, a standard car battery can keep enough to start your engine within an hour. However, full charging can take up to 10 hours. Many drivers will use a jump starter technique to get the engine running and then drive their vehicle to charge the battery.

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

Engines operating at higher RPM’s deliver higher amounts of electrical energy needed to charge a discharged battery. While a battery will charge while the engine is idling, it may take some time to completely charge your car battery.

Driving a car for 30 minutes or more should be sufficient to charge a car battery enough to restart the engine easily. One exception to the above is if your electrical system is under heavy load.

For example, with the headlights on, the electric fan operating, the radio, high powered speakers, and other custom installed items drawing power, your battery may be draining even with the engine idling.

This may be considered an extreme situation by most readers. However, the point is that it requires additional time for the battery to recharge while under heavy electrical load.

Car usage cycle

Experts suggest that a car usage cycle should include driving a car at least once a week to fully recharge the battery and to lubricate the various engine and transmission components.

Even when the car is not running, batteries will slowly discharge. Thirty minutes of operation fully recharges the battery and helps in maintaining your battery at an optimum level.

Initial charge time duration 

The initial charge time it takes to completely charge your car battery after a full discharge can vary a great deal. Driving the car for 30 minutes on the highway is usually sufficient.

A small linear battery charger may take a full day, while a multi-stage battery charger may fully charge the battery in a few hours. The higher the amperage rating of the battery charger, the shorter the time that is needed to charge the battery.

What options do I have if nothing works? 

If the battery is fully discharged, there are several options that can be used to recharge the battery. However, drivers should determine why the battery is discharged. For example, check the following:

  • Look for broken belts
  • Verify that all connections are tight
  • Did someone leave the car lights on
  • Is the battery beyond its anticipated life cycle?

Confirmed that the battery is good and the connections are tight. Use one or all of the options to recharge the battery:

  • Jumpstart the car battery with jumper cables and drive the car for at least 30 minutes
  • Attached a multi-stage or linear car charger to recharge the battery
  • Purchase and install a new battery

How Long Does It Take To Charge A Dead Car Battery?

The length of time it takes if a car battery is dead depends on the amount of amperage delivered to the battery by the battery charger. Higher amperage chargers will charge a battery faster than a low amperage charger.

Dead car batteries can be recharged in less than an hour or as long as a full day, depending on the amperage of the charger. Some batteries fail and cannot be recharged at all.

A car battery that has been discharged may still be recharged if it has not been damaged by age or by overheating from rapid discharging or previous charging cycles. Damaged batteries must be replaced.

How long does it take to Charge a Car Battery with a Trickle Charger?

Use trickle chargers to maintain your battery completely charged over a long period when your car is not being used. All batteries slowly discharge whether they are connected to your vehicle or not. Also, electronics on your car will draw a small amount of electrical power even while not in use.

A fully discharged battery connected to a trickle charger may take a full day to return it to a level where It has sufficient power to start your engine. It may take several days to return it to a fully charged state. Most trickle chargers will shut off once the battery is completely charged.

What car battery charger should I use?

Car battery chargers are manufactured with a variety of capabilities. The type you purchase depends on how you intend to use the battery charger.

Is it for emergencies to recharge a dead battery? Is your car going to be parked for a long time, and you want to avoid fully discharging the battery? What charging rate do you want to use to charge your battery?

Trickle chargers can be connected to maintain a battery at a fully charged state when a car is left unused for long periods. Low amperage battery chargers can be used when you are not in a hurry and can afford a few hours to recharge the battery.

Higher amperage battery chargers are preferred when you need to quickly charge a battery and be on your way with your car. Decide what your needs are to charge my car battery before making a purchase.

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

Mechanic connecting car battery charger cablesThe length of time to charge a car battery with a 12-volt charger depends on the amount of current or amps that the charger is capable of delivering. Higher rated chargers in terms of amperage will charge a car battery faster than lower-rated chargers.

Trickle chargers deliver two amps typically and will take a long time to fully charge a car battery. Higher rated chargers, e.g., 40 amps, will fully charge a car battery in an hour or less. Always match the circuit voltage of the charger with that of the battery.

How Long Does it Take to Charge a Car Battery at 40 amps?

A 40-amp charger can fast charge your battery. The charger may take one hour to charge your battery, and often providing sufficient charge to start your car in a few minutes, avoiding the need to ask someone to help you jump start your engine.

The amperage rating of the battery determines the time needed to charge the battery. These fast chargers can damage your battery if left connected for an extended period.

Smart chargers detect a completely charged battery, lowering the amperage down to trickle charging levels or even shutting off completely.

How Long Does it Take to Charge a Car Battery at 12 amps?

Car batteries are manufactured to deliver a variety of amp-hour capabilities. For example, a 48 amp-hour deep cycle battery will take approximately 4 hours to reach a fully charged state.

Again, consumers should consider purchasing a smart charger that reduces the current delivered once the battery is fully charged to avoid long term damage to the battery.

How Long Does it Take to Charge a Car Battery at 10 amps?

A battery charger capable of delivering ten amps will take almost 5 hours to charge a 48-amp deep cell battery.

There are different types of batteries on the market, and each of these may take less or more time to charge fully. Always purchase a smart charger that reduces the current delivered to the battery once the car battery is charged in full.

Charging a Battery at four amps vs. Charging Battery at Two amps

At 4-amps, a battery charger can take up to 12 hours to fully charge our 48-amp deep cycle battery. Deep cycle batteries deliver energy for longer periods but have less instant energy. Starting batteries provide higher bursts of energy suitable for engine cranking. Many midsize cars use dual-purpose batteries, which are optimized for both situations.

A 2-amp charger can take up to a full day or 24 hours to fully recharge a battery depending on the type of battery being charged. These low amp chargers are often combined with smart technology and used as trickle chargers to maintain a battery at full charge. A trickle charger delivering 2-amps can recharge a battery as well as keep it at a completely charged state.

Can a completely dead battery be recharged?

We all know the feeling that cranking produces when you try to start your car. That’s is why we encourage our readers to make sure they get a portable car jump starter for those situations. Most of the time, it is a problem with a faulty battery that can cause this.

The alternator is not designed to charge a dead battery, but another amp charger can recharge it as long as the battery is not defective. Even with a low amp charger, you can expect to recharge a faulty battery within 24 hours if the time that is was connected.

Different types of chargers

Smart charging technologyThere is a large variety of battery chargers. However, they fall into three main categories: Linear chargers, multi-stage chargers, and trickle chargers.

Trickle chargers are often used to prevent a battery from fully discharging over a long period, although trickle chargers cannot support batteries under load. Linear battery chargers are among the least expensive due to their small size and straightforward design.

A multi-stage charger can safely charge a car battery that has been fully discharged and maintain it completely charged, similar to a trickle charger. Most can sense the condition of the battery and apply a voltage and current appropriately to prevent damage to the battery.

Linear charger

Linear auto battery chargers use a pass transistor to change the AC voltage to DC voltage and current used to recharge your car battery. Linear battery chargers tend to minimize both size and complexity. Either a MOSFET or a bipolar transistor is typically used in these types of car battery chargers.

Multi-stage charger

Multi-stage chargers detect the condition of the battery and then deliver the appropriate voltage and current to charge the battery. The first stage is the bulk stage and delivers as much current as possible.

Once the battery is charged to 85%, it switches to the absorption stage to complete the full charge. The absorption stage is the final stage, where the battery charge is maintained.

Trickle chargers

Trickle chargers maintain the battery at a completely charged level. The trickle charger can meet a rate equal to the self-discharge rate of a fully charged battery.

However, it cannot keep a car battery completely charged if it is under load. Trickle chargers are typically used when your car is not used for an extended period.


Basically, the car battery charger that you choose will then determine how long it would take to charge a car battery. The precise number of how long does it take will most likely be a wide range of time.

We always recommend replacing a dead battery if it is giving you problems to start your car. So, how long does it really take to charge a car battery with a low amp charger? A car battery can take up to 24 hours to charge in full sometimes.

Make sure you have enough time in your hands if you decide to charge your car battery instead of replacing it. Only if the body shop has a 40 amp charger you can expect to receive the car battery within an hour of charging.

Now you know that the charging time can be very long. Just expect to wait between 1 hour and 24 hours of charging time as the standard range. The amp charger will determine how long your wait time is.

Last Updated on: January 11, 2023

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