How to Charge a Car Battery?- Quickly and Safely

Sooner or later, most drivers encounter the inevitable inconvenience of a dead car battery. You don’t have to be an experienced auto mechanic to know that your car won’t start at all without a running battery. In this situation, you need to call roadside assistance or find a way to take your vehicle to a workshop. Both options are far from ideal.

Alternatively, you have the option of avoiding these choices and charging your car battery yourself. As long as you have the right gear like a portable battery charger, you can perform this task anywhere you need it, even if you’re stuck at the side of the road.

Let’s break down how to charge a car battery.

What Does a Car Battery Do?

Before we charge ahead, you should know what a car battery does. It serves two purposes:

1. It Gives Your Car the Power It Needs to Start.

The battery delivers voltage to the starter by transforming chemical energy into electrical energy.

2. It Keeps Your Car Running.

The car battery delivers a constant voltage current to keep your engine and accessories (like your radio, headlights, and all onboard computers) running.

If your battery is too weak or too old, it cannot do both. You may need to charge your car battery if your engine starts sluggishly or slowly, or if your battery is completely dead.

Beyond starting your car, charging your battery can help you determine whether or not it’s time for a new one. For example, leaving an interior light on overnight will drain your battery, but if the battery is “healthy” it should recharge quickly. However, a battery that needs to be replaced will not hold a charge or will need to be charged multiple times.

What to Do Before Charging a Battery

Now, let’s get into the nitty-gritty. Start with these five steps before you try to charge or jumpstart a car battery.

  • Refer to your manual: Every car is different and your manufacturer might have specific instructions for your make and model.
  • Be safe: Make sure you’re charging the battery in an area where there aren’t any flames, sparks, or smoke. Also, take off any jewelry, as it can be a safety hazard. Additionally, slip-on safety gloves and glasses.
  • Sniff around: Do you smell something that reminds you of rotten eggs? If so, the battery might be leaking dangerous gas and you should not try to charge the battery. Stay away from the car, get it towed, and let a professional take a look.
  • Check the heat: Heat rising from the battery case might mean it’s been working harder than it should. Keep the hood up and let the battery cool before trying to charge it.
  • Look for corrosion: Generally, corrosion looks like a greenish, crusty substance around your battery ports. It’s a product of battery acid fumes coming into contact with the air and it’s pretty common in most lead-acid batteries. However, it can compromise your car’s electrical system and make it harder for the battery to receive the charge. You can remove the corrosion by cleaning it up with a brush and a paste-like mixture of water and baking soda.

How to Charge a Car Battery?

Before you start charging the battery, you’ll need first to prepare it. To do so, start by determining whether you need to remove your battery from your car to perform the charge. Some car batteries must be lifted out of their holding trays, while others can be charged as they are. In most conventional vehicles, you will likely not have to remove the battery to charge it.

In the unique situation where you need to remove your battery to charge it, do so first before you start the charging process.

Once your battery is prepared for charging (if necessary), make sure that all electronics in your car are powered down, including any accessories such as the interior cabin light or the stereo. If any electronics remain powered on during charging, the battery may experience an electrical arc during the process. Again, make sure all power and electronics have been turned off!

1. Remove the Negative/Ground Cable, Then Positive

Having confirmed that all power is off, you can begin to remove the negative or ground cable for your car’s battery. It’s almost always a black cable marked with a “- “symbol. The positive cable will be red and display a “+” symbol.

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Your battery may also have plastic caps over its terminals that must be pried-free for you to remove the cables. If these caps are present, remove them if necessary to access the terminals.

Use a socket wrench to loosen the negative cable, then carefully pull it away from the battery. Ensure that the negative cable is situated far from the positive cable to prevent a charge from transferring between the two sources.

You’ll need to repeat the removal process for the positive cable and terminal. Move the positive cable away from the negative terminal for the same reasons described above.

2. Clean the Battery Terminals

Before you start charging your battery, it’s a good idea to clean your terminals. You can do so using a terminal cleaning brush, which looks similar to a small toothbrush and is used to clear away corrosive debris and dirt from the terminals. You can also use either a commercial battery cleaning solution or make your own by mixing baking soda and water.

Cleaning the terminals neutralizes battery acid and prevents malfunctions from occurring when you charge the battery and reconnect the terminals.

When cleaning your battery’s terminals, always make sure you wear face and eye protection for safety.

3. Connect the Charger to The Battery.

With the steps mentioned above now complete, you are ready to hook up your battery charger.

Before beginning any of the processes noted below, please note that your charger may have specific instructions for its operation. You should follow these if they contradict our guidelines below.

Here is how you need to connect your battery charger.

  • First and foremost, ensure that the charger is powered off before beginning use.
  • Next, hook the positive cable on the charging unit up to the corresponding positive terminal on your battery.
  • Repeat the process by hooking up the negative cable to the negative terminal on your battery afterward. Do not reverse these steps – the positive cable must be connected first.
  • With both cables connected in the correct order, turn your charger on. Begin by setting it to the lowest rate by default, especially if you are using the charger for the first time
  • If your charger has a timer, set it for the appropriate charge time. This timer will charge your battery for a set time. If you don’t know how much time you need to charge your car’s battery, consult your owner’s manual or an online search.

4. Prepare the Charger.

On the charger, you’ll need to adjust the volts and amps. Going with lower amps will result in a longer charging period, but it may also lead to a more reliable charge. If speed is what you’re looking for, though, flip the switch or turn the dial too high. Just be sure to follow the directions that come with the charger and any guidance offered in your owner’s manual.

5. Turn on The Charger.

If your charger needs to be plugged into a power supply, make sure it is. If not, flip it on and let it do its thing. Depending on the type of charger you have, it may stop automatically once the battery’s full or it may power off after a set period.

6. Disconnect the Charger.

After your charger has run for its desired duration and the charging process is complete, you can remove the charger’s connecting cables from your car battery. In some instances, the charger may have a meter or indicator telling you when it is safe to do so.

To safely remove the charger, make sure to power if off before touching any of the other controls on the unit. Only after the charger has been shut off is it safe to remove the cables. Once powered down, remove the positive cable first, followed by the negative.

After removing the cables, don’t forget to replace the cables on the terminals for your car battery. Again, make sure you reconnect the positive cable before replacing the negative and be sure to use your wrenches to screw on any nuts or bolts as needed. If you removed the car charger entirely, you will need to set it back into its tray and replace the hold-down clamp.

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Once reconnected, you are finished. That’s all there is to it!

How long does it take to charge a car battery?

If the battery voltage is below 11.85 and your charger is putting out a 5-amp charge rate, it will take about 12 hours to fully charge a battery with 400 to 500 cold-cranking amps. The same battery will take about 6 hours to fully charge if the charge rate is 10 amps.

The lower the open-circuit voltage in the battery and the more cold-cranking amps, the longer it will take to charge the battery.

If a cell is bad, the battery won’t hold a charge. In this case, bring your battery or your vehicle with your battery to a local Meineke Car Care Center and we will change your vehicle’s battery.

Figuring Out the Real Problem

Remember, unless you know the reason your battery died (say, because you left the headlights on overnight) even though your vehicle starts and runs after you recharge the battery, something in your electrical system may be causing the problem. Expect your battery to run down again (and be happy if it doesn’t).

If your battery soon weakens or gives out, consider removing it and hauling it down to an auto-parts store. Many will test the battery for you, and you can pick up a new one while you’re there. Alternatively, jump-start your vehicle and get it down to a repair shop. You either have a bad battery or an electrical-system issue; you’ll need the help of a technician to solve the problem.


What is the proper way to charge a car battery?

Hooking up the Battery Charger

  • Make sure the charger is off.
  • Hook-up the positive cable on the charger to the positive terminal on the battery.
  • Hook up the negative cable on the charger to the negative terminal on the battery.
  • Set the charger to the slowest charge rate.
  • Turn on the charger and set the timer.

How long does it take to charge a car battery?

Charging a regular car battery with a typical charge amp of around 4-8 amperes will take about 10-24 hours to charge it fully. To boost your battery enough to be able to start the engine, it would take around 2-4 hours. The best way to maintain a long life for your car battery is by recharging it slowly.

Can you fully charge a car battery with jumper cables?

Jumper cables can supply power via a functional battery from another car. Keep a set in your vehicle. Connecting your car’s battery to another car’s battery with jumper cables is a common way to recharge a battery. Park the vehicles so their batteries are as close as possible.

Do I need to disconnect car battery before charging?

If they look dirty or corroded, you’ll need to clean them before charging your battery. Disconnect your car battery. Although charging a car battery while still connected or in situ is possible, it’s always a good idea to disconnect the battery before charging after a quick clean.

Can a car battery go dead from sitting?

Under normal driving conditions, your vehicle’s alternator charges your battery while you drive. But if your car sits unused for an extended time, it could hurt your battery. And if your battery is 3 or more years old, it could prove deadly for the battery.

How do you charge a completely dead battery?

Can I start my car while battery is charging?

Yes, you can start your car when hooked to a Tender. Care must be taken to make sure that the cable is clear of all moving parts under the car’s hood. Keep in mind that the tender will not jump-start a car and if the battery is too drained it will not charge it.

How long to charge a car battery?

Charging a regular car battery with a typical charge amp of around 4-8 amperes will take about 10-24 hours to charge it fully. To boost your battery enough to be able to start the engine, it would take around 2-4 hours.

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How long does a car have to run to charge a dead battery?

Remember: After you’ve done a jump-start, you’ll need to keep the vehicle’s engine running for around 30 minutes to allow the alternator time to charge the battery sufficiently.

Can a completely dead battery be recharged?

It is possible to recharge a dead battery, and depending upon the situation you are in, a dead battery is generally an easy fix, whether you are stuck in your garage and can handle it yourself or you are in the middle of nowhere and need professional, quick, and efficient service in the blink of an eye.

Will idling a car charge the battery?

Does the Battery Charge if You Let the Car Idle? The simple answer to this question is yes, your car’s battery will start to charge as long as your engine is running.

Can you leave a car battery charger on too long?

Even though there is no risk of overcharging with the use of a high-quality charger, the battery should not remain connected to the charger for more than 24 hours. A full charge is usually achieved by charging overnight.

How do you know when a car battery is fully charged?

To check the voltage you’ll need a voltmeter, which can be purchased cheaply from most major automotive parts stores. Check the voltage of your battery using the voltmeter to help determine your next course of action. 12.6V volts or above – Your battery is healthy and fully charged.

How often should you start your car?

Ideally, you want to start up your car at least once a week and drive it around for a good 20 minutes to help recharge the battery and get the fluids running.

What drains a car battery while it is off?

What may drain a car battery when it’s off are things such as interior lights, door lights, or even bad relays. While your engine runs, the alternator recharges the battery which is why you typically don’t have to worry about the battery dying while you’re blasting the radio on your drive to work!

How do you know when your car battery is low?

7 Signs Your Car Battery is Dying:

  • The Check Engine Light is On.
  • The Engine is Slow to Start.
  • The Lights Are Dim or You are Experiencing Electrical Issues.
  • The Battery Connectors Are Corroded.
  • You can smell something rotten.
  • Your battery case is misshapen.
  • Your battery is old.

Can a battery be too dead to jump?

No, the battery cannot be too dead that it cannot be jump-started. First of all, this is a chemical element. So, naturally, it can’t just “stop working” without a single symptom. There is not a chemical reaction that could immediately interrupt itself under these conditions.

Why does my car battery died after sitting for a few days?

A car battery that dies after sitting for a few days will either need replacing due to age or be suffering from a parasitic drain. A badly wired radio, a faulty relay, or a phone charger left plugged in could all be drawing power from the battery while the car is sitting.

How long can a car sit without being driven?

If you have not prepped your vehicle for a long time of not driving it you should not let it sit for more than one month, and even then, you should try to start it up and drive it for 15-30 minutes a few times within the month.

How long does it take to charge a completely dead battery with jumper cables?

It’s very important to drive around for at least 15 minutes to fully charge your battery again. The process for using a battery charger to boost a dead battery is essentially the same, you’re just swapping a functioning battery for a charger.

How long does it take for a car battery to charge with jumper cables?

Charging a dead car battery takes between four and 24 hours for a full charge and is related to the number of Amperes used in the charge and the number of Amperes in the car’s battery. It takes 10 hours to fully charge a 52Ah battery from dead to fully loaded but the car probably could be started within an hour.

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