DIY

How to Replace a Car Battery

Reading Time: 5 minutes

Most car batteries need to be replaced every four to five years. In hot climates, the service life of a wet cell lead-acid battery may only last for two to three years.

There are several factors that can cause premature battery failure. For example, not driving your vehicle long enough to fully charge your battery may cause it to remain chronically undercharged, shortening its natural service life. Also, mishandling and severe vibrations can loosen or short out an internal cell plate, which can cause sudden battery failure.

It’s usually easy to determine when your battery is nearing the end of its service life. A failing car battery will not be able to hold a charge, and it won’t be able to provide enough power to start your engine. Once this happens, it’s best to replace your car battery right away.

To learn how to replace your car battery on your own, check out our guide below.

car battery replacement
Most car batteries last for four to five years.

Car Battery Replacement: How-To

If your battery needs replacing, and you’d prefer to do it yourself, below is a step-by-step guide to help you through the process.

Replacing your car battery can be divided into three major steps: preparing what you need, removing your old battery, and installing a new one.

Note: The following are general guidelines for educational and entertainment purposes only. Consult a repair database or repair manual for specific repair instructions and recommended safety procedures.

Tools Needed to Replace a Car Battery

You’ll need a wrench to loosen and tighten the battery clamp bolts and nuts, as well as a ratchet, extension, and a socket for the battery hold-down. You’ll also need latex or nitrile moisture proof gloves to protect you from leaked battery acid.

Finally, don’t forget your safety glasses.

Some car manufacturers recommend the use of memory savers to prevent issues after installation. Your radio presets and other operator preferences may be cleared out once you install a new battery. You may even be required to re-enter a security code to get your stereo working again.

Not all car manufacturers will require a memory saver. It is important to be aware of your car manufacturers specifications before proceeding with replacing your car battery.

replacing car battery
Some car manufacturers recommend the use of memory savers to prevent issues after installation of the new battery.

Car Battery Replacement Instructions

Now that you’ve got all the materials you need, it’s time to get started on replacing your car battery. Here is a step-by-step guide on how to do this procedure safely:

Car Battery Removal:

  1. Put on your safety glasses and protective gloves.

  2. Locate the positive (+) battery terminal and take note of it. This will help you install your new battery correctly.

  3. Loosen the screws on the cable clamps to disconnect the battery terminals.

  4. Remove the negative (-) cable before the positive cable.

  5. After disconnecting the battery terminal cables, you may now unfasten the battery hold-down strap. If your battery uses a base clamp instead of a metal hold-down strap, loosen the bolt holding the clamp against the base of your car battery.

  6. Lift the battery out of its tray or compartment. Usually, the battery will have a strap on top to make removal easier. If it doesn’t come with one, you may use a battery carrying tool to hold the battery and lift it out.

  7. Make sure to keep your battery in an upright position to prevent spilling battery acid out of the caps or vents. Of course, if you’re using an absorbent glass mat (AGM) battery, you won’t have this problem as it doesn’t hold liquid.

  8. Once you’re done removing the car battery, make sure to inspect the battery tray underneath. If it is damaged or corroded, replace it right away. This will also be a great time to clean, inspect, and check other battery components. For example, if you notice loose or corroded cables, have them replaced too.

Warning: Battery acid can cause painful burns. If you accidentally touched leaked acid, wash your hands immediately with water and neutralize the acid with baking soda.

checking car battery capacity
You can check the capacity of your new battery using a digital voltmeter.

Car Battery Installation:

Now that you’ve successfully removed your old battery, it’s time to install the new one.

  1. But wait⁠—before installing your new battery, make sure to test its charge level with a digital voltmeter. If you don’t know how to test a car battery, you may refer to online repair manuals and guides.

    Ideally, a fully charged battery will yield a voltage reading of about 12.6 to 12.7 volts. If you get a lower voltage reading, you’ll need to charge the battery before you can install it. Although car batteries usually come precharged, they may slowly lose their charge, especially if they remain unused or shelved for a prolonged period of time.

  2. Place your battery on the tray. You may now install the base clamp or strap.

    Make sure to safely secure the battery by tightening the clamp or strap, as excessive vibration can damage your car battery.

  3. Clean the battery posts with a battery post cleaning tool. Clean the inside surfaces of the clamps attached to your battery cables as well.

    A clean surface will help ensure efficient electric contact.

  4. Install the positive cable, then the negative cable.

  5. Tighten the clamps—but be careful not to over-tighten as you may end up damaging them.

  6. To prevent corrosion, apply a thin coating of battery terminal grease on the clamps and posts. You may opt to install anti-corrosion washers on each post as well to help prevent corrosion before installing your battery cables.

  7. Make sure to double-check all connections, straps, and clamps. Your car battery should be safely installed at this point.

    You may start your vehicle to make sure that everything is working as it should.

If your vehicle doesn’t start or crank, try cleaning and tightening the battery cables. Check for other loose cables including the one connected to the chassis ground and the power center.

Then, try starting your vehicle again. If it still won’t start, chances are your vehicle may have another underlying issue, such as a starter circuit problem. Have your vehicle inspected by a professional mechanic to get a proper diagnosis.

Helpful Tips on How to Replace a Car Battery

If you’re a visual learner, here’s a helpful video that should give you an idea of how the car battery replacement process should go:

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CarParts.com

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In the Garage with CarParts.com is an online blog dedicated to bringing DIYers and devoted car enthusiasts up to date with topical automotive news and lifestyle content. Our writers live and breathe automotive, taking the guess work out of car repairs with how-to content that helps owners get back on the road and keep driving.

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