If you test your battery and find that it is not performing as it should be then you will need to replace your battery. This is not as big a job as it sounds and it is definitely possible to do it yourself, as long as you are very careful. Faulty batteries can be very dangerous for a number of different reasons. The acid inside them is extremely corrosive and if there are any leaks it can do a lot of damage. Electricity itself is very powerful and if you connect the wrong wires to the wrong connection points then you could end up seriously injuring yourself or seriously damaging your vehicle..
How to replace a car battery
- Firstly, make sure that you have parked on a level surface in a place with enough space for you to obtain full access to the bonnet and the engine. Some cars automatically lock the doors when you start to replace the battery (the electrical system overrides the central locking), so keep the keys outside of the vehicle.
- Put on protective eyewear and thick gloves. Battery acid is highly corrosive and can cause permanent damage if it comes into contact with your eyes or skin.
- Before you disconnect anything, make sure that you have all of the security codes for the electrical components of your car. Radios, Sat Nav’s etc. will probably ask you to put in a code once you have replaced the battery and you will be unable to use any of these features until you have entered the correct number. It is worth checking your car’s manual before you replace the battery so that you know which settings will need to be reset once you put in the new battery.
- Open the bonnet and secure the lid in place.
- Find the battery, it shouldn’t be too difficult to locate. Most of them are next to the engine but in some makes and models of car they are to be found in the boot or under one of the seats.
- If it is difficult to tell the wires which connect the battery apart then you should label them as positive and negative before you disconnect them. Rewiring the car in the wrong order could seriously damage the electrical system.
- Disconnect the negative cable, making sure that the clamp doesn’t make contact with any metal components of the engine.
- Do the same for the positive cable.
- In different cars the batteries are held in place in different ways. Remove any clips or screws securing the battery making sure to keep hold of any pieces you remove in case the new battery doesn’t come with new clips or screws.
- Carefully take the battery out of the vehicle. Be warned, batteries are quite heavy and can be awkwardly positioned so you may need another pair of hands to help you remove it safely.
- Prepare the new battery by removing any packaging and covers. Double check that the battery you are about to put in is the correct model for the car.
- Screw or clip the battery back in to place.
- Reconnect the positive cable first, taking care to ensure that it is securely fastened in place and that the cable is not in the way of anything else. The clamp should be as close to the base of the post on the positive terminal as you can get it.
- Then reconnect the negative cable, taking care to ensure that it is securely fastened in place and that the cable is not in the way of anything else. Again, the clamp should be as close to the base of the post on the negative terminal as possible.
- Double check that there are no loose screws, out-of-place cables or stray bits of packaging.
- You can start the car. If the replacement has been successful, the engine will start and there will not be any warning lights on the dashboard.
- Enter all of the security codes to restart your electrical equipment and you’re good to go!
If the car doesn’t start then there is a good chance that you have done something slightly wrong. Don’t try to correct the problem yourself unless you are 100% sure of what the problem is. You could ruin the whole of your vehicle’s electrical system which would be a much bigger job to sort out.
Points to consider
Make sure that you are parked on a flat surface so that the battery acid remains level. Don’t forget to wear gloves and protective goggles so that the acid doesn’t come into contact with your skin. Whenever you work with a live current you need to be extremely careful not to short circuit any systems and not to electrocute yourself. If at any time you have any doubts whilst replacing your battery, take your vehicle into a workshop and get a professional to finish the job for you, safely and to a high standard.