Basic Car Maintenance: How to change your car battery yourself
Friday, 25 August 2023
Even if they’re well taken care of, car batteries don’t last forever. The typical lifespan of a car battery is between three and five years before it needs replacing. If you notice your headlights dimming or your car has run out of energy, the likelihood is that it needs a new battery. Fortunately, this is something which you can tackle at home with a few tools and without too much difficulty.
Why do car batteries go flat?
Car batteries can go flat for several reasons, including:
- Undercharging, caused by lack of use or when the car is only being used for short journeys which don’t give the battery time to recharge fully.
- Leaving headlights or interior lights on for extended periods.
- Corroded or loose battery connections can prevent the battery from charging properly while you drive.
- Extremely hot or cold temperatures which can exacerbate underlying problems with your battery.
How will I know my car battery needs replacing?
If your car won’t start at all, the battery is completely dead and needs replacing. If you want to check the condition of your battery before it fails, an easy test is to start your car in the dark with the headlights switched on. If the headlights are overly dim, place your vehicle in park and rev the engine. If the battery is failing, the headlights will get brighter as you press the accelerator and you need to replace it.
Is it easy to replace your battery?
Unless your car battery fails while you’re away from home, changing your car battery is something many people can do themselves. Normally, the hardest part of changing a car battery is lifting it out of the vehicle once it has been disconnected due to the weight, so it can help to have someone else on standby.
What should you do before changing your car battery?
- Ensure you’re parked on a flat, level surface with the hand brake on and the keys out of the ignition.
- Make sure you’ve got goggles, gloves and protective clothes on to protect against the corrosive acid contained in the battery.
- Take note of all your pin codes for your radios, sat navs and other electronic equipment as some cars will reset when the battery is disconnected.
What tools do I need to replace my car battery?
- Socket set
- Replacement battery
- Battery tester (optional)
How to replace your car battery:
- Open the bonnet and (if your car has one) use the stay to keep it held up.
- Locate the battery. It will nearly always be found beneath the bonnet, but on some cars, it will be in the boot. The best way to check is to refer to your owner’s handbook.
- Remove any of the plastic trims or covers from the battery.
- Label the battery cables so that you don’t get them mixed up.
- It’s important to disconnect the negative connection before the positive – not doing so may cause damage to your vehicle’s electrical system.
- Loosen and then disconnect the negative cable clamp (which should be marked ‘-‘ [minus]) and move the clamp away from the battery post.
- Disconnect the positive cable clamp in the same way.
- Remove any screws, bars or clamps that continue to hold the battery in place, and then disconnect any vents that are attached. You can then carefully lift the battery from the vehicle.
- Fit the new battery by sliding it into place, ensuring that the negative and positive posts are on the correct sides.
- Re-connect any screws, clamps or bars, and re-attach any vent pipes.
- Remove any covers from the new battery terminals.
- Reconnect and secure the positive cable clamp (keep it as far down the battery post as possible).
- Do the same for the negative cable clamp. Again, keep it as far down the battery post as possible.
- You should now be ready to start the vehicle.
- Remember, if you’re at all unsure about replacing car parts, consult an expert.
Where can I recycle my car battery?
By law, car batteries must not be disposed of with household waste. Most garages, recycling centres or scrap metal facilities will have collection points where you can dispose of old car batteries.
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