How to replace your car battery safely yourself

Last updated on November 14, 2023
Knowing how to change a traditional car battery yourself is a helpful skill any car owner can learn. Save money and avoid the headache of getting stranded with a dead battery by changing your petrol or diesel car battery yourself at home.
Gloved installer replacing a battery in a vehicle
When you’re equipped with the right tools and knowledge, it’s quite a straightforward process. In this guide, we’ll walk you through the step by step process to safely change your petrol or diesel car battery, without needing to find a mechanic to handle it for you.
To make sure you’re prepared, we’ve listed some important things that you’ll need to know to change your battery safely and successfully yourself.

Before you start to remove your car battery, you’ll need to put some essential safety measures in place.

  • Familiarise yourself with the process for changing your battery by reading this guide and checking your car’s manual
  • Perform your battery replacement during daylight hours for good visibility
  • Make sure that your car is parked on level ground, the engine is switched off, and the handbrake is on

Make sure you have the following tools ready before changing your battery:

  • Adjustable wrench for removing the battery terminals
  • Cleaning cloths or rags to wipe away any dirt or corrosion
  • Adjustable pliers for loosening clamps
  • Gloves to protect your hands
  • Appropriate eye protection
  • A towel to protect your car from acid in the case of a potential leak
  • Your replacement battery

To find the specific battery you need, you can refer to two sources:

  • Your car’s owner manual: this will include details of the battery type, size and specifications.
  • A battery manufacturer’s reference guide: many battery manufacturers offer online tools and guides to help you find the correct battery for your car.

The time it takes to replace your car battery yourself will vary depending on your experience level and the specific circumstances. The process usually takes from 30 minutes to an hour.

If you’re new to changing car batteries, leave yourself more time for any unexpected delays, such as:

  • Difficulty locating your battery within your car
  • Corrosion or rust that requires a more thorough clean
  • Time to learn how to replace your battery
  • Additional car maintenance needs you might notice while changing your battery

To remove the old battery from your car safely, follow these key steps:

  1. Find the battery’s location in your vehicle. It may be located near the engine, in the trunk, or even by a wheel. You can also check your vehicle owner’s manual to find your battery.
  2. Wearing safety gloves, eye protection and using a wrench, disconnect the cables from the battery terminals. Start with the negative terminal first: it will be labelled with a minus sign or NEG. You’ll need to loosen the bolt using the wrench, then once loose, gently twist the cable connector back and forth as you lift it up and remove it from the battery terminal. Then remove the positive terminal.
  3. Remove the screws or fasteners holding the battery in place and put them somewhere safe where they won’t roll under the car.
  4. Remove the battery. To do this, use both hands to carefully lift the battery out, keeping it upright at all times. Place it on a stable surface.
  5. Check the tray the battery was resting on for signs of damage, such as rust or corrosion. You can use your cleaning cloths or rags to wipe the area clean.

CAUTION: Be careful not to let any metal objects touch both battery posts at the same time.

To safely install your new car battery, follow these steps:

  1. Examine the terminals attached to the ends of your battery cables. If they show any signs of dirt or corrosion, you can clean them using either a terminal-cleaning tool, or a wire brush. The cleaner they are, the better connection your battery will have.
  2. Position the battery on the tray. Make sure it’s facing the same direction as the previous battery or that the positive and negative terminals are on the correct side, and that it’s firmly seated within the tray.
  3. Replace the battery screws and fasteners. Tighten with an adjustable wrench or socket set to secure your new battery firmly in place.
  4. Reconnect your battery cables in the reverse order to how you removed them, by attaching the positive first and then the negative.
  5. Close the hood and start your car. Most new car batteries will come charged and ready to go. See ‘Testing’ further on in this guide.

Note: Changing your battery may clear your vehicle’s memory or security codes. This might require you to re-enter any codes to resume access to your car’s systems, for example your stereo system.

Car batteries are corrosive, so they must be properly disposed of and can’t be thrown away in ordinary rubbish bins. Responsible disposal is an important step to avoid battery leaks, and to protect the environment.

You must tape up the battery terminals to prevent accidental contact or acid leaks. You can then recycle the old battery at many local or community recycling centres, which ensures they are appropriately processed to avoid harm to the environment.

You can perform a quick test to make sure you’ve successfully replaced your battery.

Turn on your car and check that the electrical systems such as the air conditioning and lights are working correctly. If everything is working as expected, you’ve changed your battery successfully.

If you suspect a dead battery, it’s worth remembering that the underlying problem may be something else, such as a faulty alternator or starter motor.

By regularly checking and maintaining your car’s battery, you can prolong its lifespan and have a clearer picture of whether there are possible issues with your battery. As with all car maintenance, this can help to avoid unexpected issues or breakdowns.

Before you purchase car insurance, take some time to compare car insurance policies and understand which events are included – and not included and which cover is right for your needs. Our car insurance products don’t provide cover for flat batteries. Learn more about our Car Insurance or contact us.

This article has been prepared by Allianz Australia Insurance Limited ABN 15 000 122 850 AFSL234708 ("Allianz"). In some cases, information has been provided to us by third parties and while that information is believed to be accurate and reliable, its accuracy is not guaranteed in any way.

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