How to Avoid Car Battery Failure This Winter

As we head into winter and the temperature begins to drop, your car battery faces its biggest challenge of the year - the cold. Cold weather slows down the chemical reactions inside your car battery which reduce its ability to hold charge. If it’s already getting old, it could fail when you need it most. A flat battery is a common cause of breakdown but with the correct care and the right breakdown cover, you'll be able to keep driving through the winter.

Why Car Batteries Fail in Winter

When the cold temperatures slow down the chemical reactions inside your car battery, it struggles to hold and deliver charge effectively. In addition to an increased use of other electrical components like headlights, heaters, and windscreen wipers during the darker months, your car battery is under a lot more strain. A battery that is working well in summer might actually be weak or ageing and the cold weather will quickly expose any underlying problems.

Other Common Causes of Car Battery Failure

Age

Most car batteries last between three to five years. After this, their ability to hold charge naturally declines. If you can’t remember the last time your battery was replaced it’s probably past its prime.

Corrosion

Build-up around the terminals can prevent the battery from conducting electricity efficiently.

Overcharging or Heat Damage

Prolonged exposure to high temperatures can cause the battery case to swell, leading to leaks and long-term damage.

Parasitic Drains

Leaving lights, radios, or chargers plugged in can drain your battery even when the car is off.

Warning Signs Your Car Battery Might Be Failing

If your electrical components like your lights, windows, radio or air conditioning seem to operate sub optimally and seem sluggish this could suggest your battery is struggling.

Hearing a clicking sound as you turn the key in the ignition is a sign you battery is struggling as there is not enough power to start the engine.

If you lift the bonnet up and see a swollen battery case this could suggest your battery has gotten too heat and this heat has built up. It’s also a sign that your battery has struggled with overcharging. Swollen battery cases can lead to leaks that damages surrounding components.

Equally, a blue or white powdery residue on terminals is the sign of a corroding battery. The corrosion from leaking acid can interfere with other electrical connections and can also hinder the battery’s ability to conduct electricity effectively.

How to Check the Health of Your Car Battery

If you think you have come across some warning signs that your car battery is failing you should then check the health of your car battery. You can do this a few ways.

1. Use the Built-In Indicator

Modern car batteries include a simple built-in indicator that is displayed on the dashboard. Typically, a green light means that the battery is healthy, red suggests it needs charging, and a blank or dark indicator means the battery is flat and needs replacing.

2. Visual Inspection

Lift the bonnet and look at your battery. If the casing looks swollen or cracked, don’t attempt to start the engine as the battery needs replacing.

Check that the battery terminals are firmly attached and free from grime.

If you notice a white or blue powdery residue around the terminals, this is corrosion and this can reduce electrical contact.

How to Clean Battery Corrosion Safely

As battery corrosion can affect performance and even cause electrical faults, cleaning it is important. To do this:

1. Wear protective gloves and safety glasses.
2. Disconnect the negative (black) terminal first, and then the positive (red).
3. Mix baking soda with warm water to make a gentle cleaning solution.
4. Use a wire brush or cloth to scrub away the corrosion. Don’t pour the solution directly onto the battery.
5. Dry thoroughly and reconnect it – positive terminal first.

3. Testing with a Voltmeter

After doing a quick visual inspection, a voltage check is also not a bad idea for getting an understanding of your battery's health. To do this, you first need to turn off the ignition, lights and any accessories.

Then connect the red (positive) lead of the voltmeter to the positive terminal and the black (negative) lead to the negative terminal.

A healthy battery should show 12.4V-12.7V. Anything lower than 12.3V means it’s partially discharged and will soon need to be charged.

If your battery is showing low voltage, it is worth charging it before the cold weather sets in.

How to Charge Your Car Battery Safely

To keep your battery topped up, use a smart charger or a trickle charger as they adjust the charge automatically and prevent overcharging. To charge a car battery:

1. Disconnect the negative (black) terminal first and then the positive (red).
2. Attach the charger’s red lead to the positive terminal and the black led to the negative.
3. Set the charger to the correct mode and voltage.
4. Plug it in and switch it on. A full charge takes between 10 to 24 hours.

If you aren’t confident of charging the battery yourself, taking your car for a 30-minute drive can also recharge it. Running your battery at a low voltage for long periods shorten its lifespan.

How to Prevent Car Battery Problems

Make sure you check your battery regularly, especially before winter. If you do spot signs of corrosion clean the terminals. If you notice swelling, get your battery checked out by a mechanic.

Turn off all the lights, heaters and other similar electrical accessories before you switch off your car.

If you don’t drive your car often or only use it for very short journeys consider either using a trickle charger or a battery maintainer, or you can occasionally drive longer journeys to allow your alternator time to recharge the car battery fully.

Replace your battery when you need to – don’t wait for it to fail. If it is over three years old, it’s worth having it tested on an annual basis.

What to Do if Your Battery is Dead

If your car won’t start and you suspect the battery is flat then you should check for obvious issues like loose connections or corrosion.

Alternatively, you can try jump-starting your car with jump leads and another vehicle.

How to Jump Start A Car

If your car won’t start and you suspect the battery is flat, you might be able to get it going by jumpstarting it. To do this you will need jump leads and a car that is working normally. Follow these steps carefully:

1. Make sure the car is close enough for the leads to reach but they are not touching.
2. Turn everything off such as the ignition, lights and accessories in both vehicles.
3. Connect the red jump lead to the positive terminal of the flat battery and then to the positive terminal of the charged battery.
4. Attach the black jump lead to the negative terminal of the charged battery and then to an unpainted metal surface on the engine block of the car with the flat battery. Do not attach it directly to the negative terminal of the car with the flat battery.
5. Start the working vehicle and leave it running for a few minutes.
6. Try to start the car with the flat battery.
7. Once it's running, remove the leads in reverse order and keep the engine running for at least 30 minutes to recharged the battery.

If your vehicle still won’t start, it could indicate a deeper fault. Jump starting your car is only a temporary fix and you should have your battery checked by a qualified mechanic as soon as possible.

Breakdown Cover

Even with regular maintenance, a sudden battery failure can catch you off guard. If you find yourself stuck and unable to get going, Eversure Breakdown Cover is here to help. In that stressful moment, all you need to do is call your breakdown provider with your policy details and location ready and we’ll take care of the rest.

Final Thoughts

As your car battery is at the centre of your whole vehicle's electrical system, a little bit of maintenance goes a long way. In understanding how cold weather affects it and how to take steps to care for it, you'll be able to avoid car battery failures.