How to disconnect a car battery

Author Name – Jack Underwood

   

If you need to disconnect your car battery, whether it be to fit a replacement or clean the battery, this article will show you how to disconnect the battery safely.

disconnecting a car battery

At National, you can purchase new NAPA car batteries online and these can be fitted at your local National Tyres and Autocare branch.

We would always recommend that if you need to disconnect a car battery, that this is done by our specialists at any of our National branches. However, if for any reason this is not possible, below we outline the steps to ensure that you can disconnect your car battery in a safe and effective manner.

  1. Locate the car battery: In many vehicles, the car battery is located underneath the car bonnet. It is important to wear gloves and also safety goggles if possible to ensure that you stay protect yourself.
  2. Turn off the engine: Make sure that you have turned off the car engine and have removed the key from the ignition.
  3. Locate the battery terminals: There are two terminals that you need to identify. You will see a negative terminal and a positive terminal. The negative terminal has a minus sign, while the positive terminal has a plus sign. Usually, these can be identified by looking at the colours of the plastic caps- the negative terminal is usually black while the positive terminal is usually red.
  4. Loosen the nut on the negative terminal: Using either a socket wrench or an adjustable wrench, you need to loosen the nut on the negative battery terminal. To loosen the nut of the negative battery terminal, you need to turn this anti-clockwise. You need to remove the negative terminal first as if not, this can cause an issue to the vehicle's electrical system and is also unsafe.
  5. Disconnect the negative cable: Now that you have located the negative terminal and loosened the nut, the next step is to remove the negative connector from the negative terminal.
  6. Remove the positive cable: Now that you have removed the negative cable from the negative terminal, the next step is to do the exact same with the positive terminal, loosen the nut and remove the positive connector. Make sure that the positive terminal does not touch any metal part of the car. There will still be an electrical charge in the system that could damage the circuits.
  7. Disconnect and remove the car battery: Now the battery terminals have been disconnected, remove the car battery from the battery holding by unscrewing the brackets. After removing the battery, clean the battery tray and cables with a toothbrush that has been soaked in baking soda and hot water.

How to clean battery corrosion

Mix together 3 tablespoons of baking soda with 2 tablespoons of hot water. Apply the solution to the corrosion using an old toothbrush and leave for 10-15 minutes. Then proceed to wipe off the solution.

How to clean battery terminals

If battery terminals become corroded, this can damage the car battery. With either a toothbrush or a wire brush, mix together baking soda and water and remove any corrosion from the battery terminals.

Which battery terminal to disconnect first

You need to disconnect the negative terminal first when disconnecting a car battery. The reason for this is for safety reasons. If you were to remove the positive terminal first, this could cause electrical issues.

How to disconnect a car battery charger

If have used a car battery charger to charge your battery, you need to disconnect the negative cable first and then the positive cable. To find out how to use a car battery charger, you may find the below article useful.

Related: How to use a car battery charger

Car battery online deals

If you are looking for a replacement battery for your vehicle, fully fitted then these can be purchased via our website. We stock a wide range of car batteries which can be fitted at your local National Tyres and Autocare branch. We also stock leisure batteries which can be purchased and collected from your local branch. Our branch staff will be unable to fit the leisure battery.

Related: Battery replacement

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