How to Fit a New Car Battery

Person with glove on fixing car battery

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Flat batteries are the most common cause of car breakdowns - accounting for 19% of RAC’s 2.4million call-outs in 2012 – and motorists are more likely to suffer this type of breakdown in winter when the combination of cold temperatures and increased workloads really puts batteries to the test. However, unlike mechanical breakdowns, which require specialist attention, car batteries are often relatively straightforward to replace, so you won’t need to dig out details of your breakdown cover, But you first need to confirm it’s the battery that’s the problem, so here’s what to look out for…

Signs of a flat battery

If, when you turn the ignition, the engine cranks slowly before gradually coming to a stop and the dashboard lights dim but don’t go out, then your battery could be on its way out, or will at least be partially discharged. This is usually the result of leaving a light on accidentally - even the interior light can be enough to deaden a battery if left on for long enough. If this happens, make sure all electrics are off and wait for about 20 minutes before trying the engine again as a battery that is still in good condition may recover enough to start the engine; if not, then it’s time to replace it.

The tell-tale sign of a completely flat battery is that the engine won’t crank at all but you should be able to hear an irregular clicking sound coming from under the bonnet. If the dashboard lights go out as well then it’s time for a new battery. There are several reasons why the battery could be flat, but it’s most commonly because the car has been left to stand, particularly in the cold, or there is a drain on the current – either way, it’s time to replace it. But before you go and splash out on a new one – they don’t come cheap – make sure you first check the clamps and connections are secure and free from corrosion. If they are, and the car still won’t start then it’s replacement time. Here’s how to go about it…

How to fit a car battery

Make sure you are parked on a flat, level surface – if not, don’t attempt to replace the battery – engage the handbrake and keep the keys about your person in case your car activates the central locking when the battery is removed. You should also make sure that you have all of the PIN codes and settings for your car’s electrical systems, such as the radio or satellite navigation system, as these may need to be reset. Next you need to locate the battery, which is easier said than done in many modern engines, it’s usually under the bonnet, but could be in the boot or even under one of the seats. If you’re unsure, check the handbook.

Once you’ve found it you should put on some protective goggles and gloves – this may sound overly cautious but car battery acid is highly corrosive and can leak from cells – and then remove any plastic covers from the battery or connections. Identify the negative and positive connections (negative will most likely be black and marked ‘-’ while positive is usually red and signed ‘+’) before disconnecting and moving the negative terminal away from the battery post.

Always remove the negative terminal first as failure to do so could damage your car’s electrical system. Then do the same with the positive terminal and loosen any clamps or screws holding the battery in place before carefully removing the battery itself, keeping it upright at all times to minimise the risk of an acid spillage. Take care while doing this, and get help if necessary, as car batteries are usually quite heavy and often sited in awkward positions. Watch the strain on your back.

Fit the new battery in its place, making sure it’s in the right way and the negative and positive posts are on the correct sides, before tightening any clamps or screws to hold the battery in place. Remove any covers from the new battery posts and then securely reconnect the positive (+) terminal followed by the negative (-) terminal. All being well, you should now be ready to drive away – and remember to properly dispose of the old battery at your local recycling point, which you can find, here.

How to avoid a flat battery

Prevention is always better than cure, so here are some ways to help avoid a flat battery… Car batteries generally have a life of between three and five years, so if your battery is over five years old, then you should look at replacing it, even if it’s showing no signs of slowing down – you could save yourself suffering a breakdown. When you park up, make sure no electrics are left on – anything from the car radio to an interior light can be enough to drain the battery.

If your motoring predominantly consists of short journeys, or you regularly leave the car standing for a few days at a time, this can shorten its life by as much as half. To help avoid this you can invest in a smart battery charger which will help to keep it in optimum condition. But even the best laid plans often go astray, so make sure you have adequate breakdown cover, including home recovery, just in case your battery falls flat at your front door.

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