How To Change A Car Battery

(Last Updated On: March 15, 2024)

Despite maintaining your vehicle exceptionally well, a time will come when you’ll need to replace the car battery. Understanding the method of altering a car battery can prevent you from being stuck should your battery fail while you’re on the go.

Car batteries do have a fairly long life-span, from 5 to 7 years on average, and as much as 10 years in ideal conditions. If you drive your car regularly, you won’t need to replace your battery very often.

When your battery does need to be replaced, there are a few symptoms that will warn you before it fully dies. Difficulty starting your car and lights that are dim or flashing are often the first signs. Your car will also tell you by activating the battery light.

Once you start noticing these symptoms in your car, you’ll be glad you know how to change a car battery. Read on below to find out more.

Tools Needed To Change A Car Battery

Some of the tools you’ll need to change your battery are common and familiar—the kinds of tools most people have in their homes already. Others are more specialized and will likely require a trip to the auto parts store.

Let’s break down what tools you’ll need:

  • Wrench or socket set. The exact size and style of wrench and socket you need will depend on the design of your engine and battery. Most cars require a 10mm socket wrench. Your vehicle’s manual should give you more details on exactly what’s required.
  • Battery tester. The symptoms of a dying battery can also be caused by problems with the alternator. Test your old battery before buying a new one to make sure it actually needs to be replaced.
  • Wire-bristled brush. The plastic-bristled scouring brushes you have on-hand for dishes likely won’t be hard enough to clean automotive build-up and rust. A wheel brush or lug nut brush from the auto parts store will serve you much better for cleaning up your posts and terminals.
  • Terminal grease (optional). Putting terminal grease on the new battery makes it easier to attach and protects it from corrosion.
  • Terminal puller. These tools look a bit like heavy-duty corkscrews. They’re designed to remove corroded terminals without damaging them. You’ll definitely need one of these if there is heavy corrosion on the battery, though it may not be necessary for a well-maintained battery.
  • Protective gear. Gloves and safety glasses are a smart choice any time you’re working with your car’s engine.

How To Change A Car Battery: Step By step

  1. Open the hood and locate your car’s battery. It’s usually readily visible. If you can’t find it, your vehicle’s manual will point you in the right direction.
  2. Use a battery tester to check the battery’s operation. Even if the battery is the problem, you may only need to charge it. If the battery does need to be replaced, continue with step 3.
  3. Use a wrench to loosen the battery terminal bolt on the negative battery terminal. This will usually be black and marked with a negative sign (-). Remove the car battery cables and terminal, using a terminal puller if it won’t come out easily.
  4. Repeat step 3 on the positive terminal. This will typically be red and marked with a positive sign (+).
  5. Remove the car battery holder or restraint that holds the battery in place. Set all the pieces aside somewhere they won’t be disturbed or lost.
  6. Remove the battery gently, avoiding jostling it as much as possible.
  7. Inspect the terminals at the end of the battery cables. If you see corrosion or build-up, clean them with the wire-bristled brush. This is easier than learning how to replace battery terminals, and will usually do the trick.
  8. Position the new battery, aligning the battery’s positive post with the red positive cable.
  9. Insert the battery. Secure it in place with the restraint system you removed earlier. Try to wiggle it to make sure it’s firmly in place.
  10. Remove the plastic caps on the posts of the new battery. Apply terminal grease to both the ports and terminals.
  11. Connect the positive terminal, using the wrench to tighten it.
  12. Repeat for the negative terminal. Inspect both battery terminals’ clamps to verify they’re secure.

Tips To Change A Car Battery

Changing a battery is a relatively simple and safe repair, even if you have limited experience with car engines. Having said that, there are a few tips you should follow to protect both yourself and your car.

  • Don’t allow anything metal to touch both the negative and positive posts at the same time.
  • Don’t let your tools come into contact with anything metal while it’s touching the positive terminal. This includes the other parts of the car’s frame and engine.
  • Order is important when you’re learning how to reconnect a car battery. The positive terminal should always be the first one connected and the last one disconnected. If you notice the positive terminal is loose, remove the negative terminal before making any adjustments.
  • Preventing corrosion is the best way to extend the life of your battery. You can buy terminal grease with anti-corrosive properties. Anti-corrosion washers can also be bought at the auto-parts store. These go around the battery posts under the terminals and help prevent corrosive build-up from forming.
  • Removing the battery also resets electronic systems. This includes the clock, radio pre-sets, stored OBD2 codes, and any security alarms. Prepare for this beforehand to avoid frustration when you re-start your car.


What affects the lifespan of a battery?

How you drive your car is the biggest factor in your battery’s longevity. Letting the battery sit idle for more than a few days at a time causes it to discharge and reduces its lifespan. Draining or deeply discharging the battery will also make it die quicker.

Can I charge the battery instead of replacing it?

In some cases, yes. Many hand-held battery maintainers can even reverse some of the damage caused by deep discharges.

Consider how many more useful years you’re likely to get from the battery, however. If it’s already 5 years old or older, it’s probably more effective to simply buy a new one. You can also check out the way the batteries work to know more about it.

What should I do with the old battery?

Dead car batteries can be recycled at most auto part stores and mechanic garages. Call ahead first to make sure they offer this service.

Bonus: A guide on checking how many amps is a car battery.

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