How to change a Car Battery in 7 simple steps


Car Batteries aren’t designed to last forever and will need replacing at some point, in the UK unreliable batteries account for one of the biggest call outs for roadside assistance. 

There are a multitude of factors that affect a cars battery life and on average they last between three and five years when properly maintained. The most common causes of a flat battery are irregular use of a vehicle or only making short journeys. The vehicle isn’t given chance to charge enough which causes sulphation - a hardening of the lead plates that sit within the battery, affecting its capability to hold a charge. 

Battery performance can also be affected by temperature as they work on a chemical reaction basis; a battery operates at maximum efficiency at a temperature of 26.7℃ or 80℉. 

Leaving any electrical systems running without the engine running may also cause a battery drain which will result in a flat battery. Always ensure your lights, radio etc are turned off when your vehicle is not in use. 

It’s advisable to seek professional advice if you have not changed a battery before, however, if you are wanting to change it yourself, here’s how: 


Step 1

Locate the battery:

Ensure your vehicle is parked on a flat level surface, the engine is off and handbrake is engaged, then open the bonnet. If you are unsure where to find the battery, refer to the owner’s manual. 


Step 2

Protective equipment:

Battery acid is highly harmful and corrosive, ensure you are protected with gloves and appropriate eyewear before attempting to remove it in case of any leaks.


Step 3 

Radio / Sat Nav Codes:

It may be worth checking that you have the vehicles electrical PIN codes to hand and the car keys in reach. Changing a battery can send the head unit into safe mode which will require a code to restart. It may also activate the central locking system or set off an alarm. 


Step 4

Identify the terminals:

The battery will have a positive and negative terminal. The positive battery terminal will be marked with a ‘+’ and will usually have red wires. The negative battery terminal will be marked with a ‘-’ and usually has black wires. It is important not to let the two terminals come into contact as this may cause a spark.


Step 5

Removing the battery:

Always remove the negative terminal first. Failure to do so could damage your car’s electrical system. Next, using the socket or spanner loosen the positive terminal, then the clamps or screws securing the battery in its housing (typically found low down on the side of the battery). Carefully lift the battery out vertically (please note car batteries are heavy!) avoid tilting as this may cause an acid spillage. 


Step 6

Installing the new battery:

Ensuring the negative and positive terminals are in the same position as the existing battery, lift the new battery into its housing. Double check this before tightening the clamps or screws that hold the battery in place. Remove the plastic protective covers from the new battery posts and then securely reconnect the positive (+) terminal followed by the negative (-) terminal.


Step 7

Ready, Set, Go! 

Having followed the steps above, you should now be able to start the ignition and be ready to drive away on a full charge. Just ensure that you keep the battery in a secure upright position and dispose of it appropriately at either a recycling centre or tip.