How To Disconnect A Car Battery

If you need to remove your battery to fit a replacement, or check for corrosion, we’ve put together this handy 5-step guide so you can do it simply and safely.

1) Find Your Car Battery

Finding the location of your battery is the first step. Whilst most batteries can be found by opening the bonnet and looking in the engine bay, many modern vehicles have the battery located in the boot under the boot liner. Some vehicles may even have the battery located under the rear seat. If you’re unsure of your battery’s location check your owner’s manual.

When disconnecting the battery, you will often need to reset your dash, radio and seat position, amongst other settings. Therefore, keep handy any codes you may have just in case you need them.

2) Protect Yourself

To ensure your safety, make sure you’ve turned off your ignition and remove the key (if you have one that connects into the ignition lock). Make sure the key remains removed when you reconnect the battery. Wear safety goggles and gloves to protect your eyes and hands when inspecting and handling your battery.

3) Find the Positive and Negative Terminals

The positive terminal is marked with a ‘+’ symbol and often has a black cap. The negative terminal is marked with a ‘-’ symbol and often has a red cap. These caps will need to be removed to give you access to the battery cables and clamps that you will have to remove to disconnect the battery.

4) Find the Correct Spanner or Socket

The next step is to find the spanner, socket wrench or adjustable wrench you need to remove the nut on the negative and positive terminals. In some cases, you will be able to get away with an adjustable wrench. Remember, always start with the negative terminal when disconnecting and removing your car battery.

5) Disconnect the Negative and Then Positive Terminals

Use the spanner, socket wrench or adjustable wrench to loosen the negative terminal. This should only take a couple of left turns. Once loosened remove the negative connector and ensure it is pushed aside so that it cannot contact the battery whilst you remove the positive terminal. Repeat the same process with the positive terminal to loosen and remove the positive connector. We recommend wrapping the connectors in a rag or towel to prevent them from contacting the battery.

Once you have disconnected the terminals you can continue with the work you need to do. If you need to replace your battery you need to remove the battery hold down clamp. Not every car will have one of these, but most tend to. To remove the clamp, you’ll likely need a socket wrench as it can be found low down on the battery tray with limited access.

Whether you’re replacing a battery or simply performing maintenance you will need to inspect the battery tray and cables for corrosion. Use a toothbrush coated in diluted baking soda to remove any corrosion and leave to dry before placing in your new or existing battery.

If you are replacing your battery, ensure that you dispose of it at a local recycling centre. Alternatively, some car battery suppliers (us included) will recycle your battery free of charge as part of your service agreement.

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