Why does my car battery keep dying when it’s cold?

Monday 25th November 2024

We have all been there - you turn the key in the ignition on a cold morning, only to find the car refuses to start. You soon realise that the car battery is flat. But why do car batteries seem to lose charge quicker when the temperature drops?

Formula One Autocentres’ guide explains why your vehicle’s battery dies in cold weather and what you can do to prevent it from happening.

Why is my car battery dying?

There are many reasons why your car battery dies – including lack of use, accidentally leaving your headlights on (which inevitably drains the battery) or a fault with the battery. However, there is a strong correlation with cold weather and the effects it has on your car battery.

EV batteries and conventional car batteries: Compared

Conventional car batteries and EV batteries have many differences, from how long they take to charge to how much they cost to replace.

Here, we look at what makes these batteries distinct from one another:

• Typically, car batteries on diesel and petrol vehicles need replacing every three to five years.
• Battery-powered vehicles (EVs) have batteries that last seven years or more.
• A conventional battery works alongside the alternator to operate your car’s electronics.
• An EV’s battery stores energy that’s used to generate power for the electric motors.

So, why do car batteries die in cold weather?

Frozen battery solution

All car batteries hold their charge by using a liquid electrolyte solution. However, the solution can freeze. A discharged battery is more likely to freeze as it has a higher water content, limiting your car’s ability to transfer full power to the battery.

Systems draining your car battery’s power

How you use your car can also impact battery life in cold weather.

As winter approaches, the weather gets colder and the days get shorter, with dark early mornings and the sun setting in the late afternoon. Drivers will need to use more battery power more frequently at this time of year, to power electrical systems such as headlights and windscreen wipers.

The colder temperatures mean you need to crank your car’s heating up to full power, this will also drain the car’s battery.

Lack of use

With the colder weather, snow and ice can discourage drivers from using their vehicles. Factors that may stop drivers from using their cars include:

• Living in a rural or remote village.
• Living in an area that is particularly susceptible to poor weather conditions. Being a nervous driver who does not feel comfortable driving on icy roads.

Over time, car batteries gradually lose charge when they are not being used regularly, causing them to fail. Are you unsure what has caused your car's battery to fail? Spot the common signs of a faulty battery with our guide.

What can I do to protect my car battery in cold weather?

When it comes to protecting your car’s battery in cold weather, there are a few things you can do to prevent it from dying:

• Parking your car in a garage or investing in a battery warmer.
• Switching off your radio, heaters, lights and wipers before turning the engine off.
• Drive your car more regularly or for longer distances.
• Avoid only using your vehicle for frequent short journeys, if possible.

What to do when your car battery dies

If your battery is drained, it is possible that you can manually charge the battery yourself with a car battery charger.
Follow the instructions on the charger carefully and turn off all electric systems on your vehicle so that nothing is slowing down the charging process. Plug the charger into the mains, and your car battery will get back to a full charge. Having a car battery charger on hand ensures you are prepared for any battery-related emergencies you may encounter.

In many cases, your vehicle’s battery may have completely run out. You can kickstart a battery into life by jump-starting the battery by using jump leads and another car’s engine to do this, or a power pack.

If neither of our solutions has worked, you likely have a more serious problem with your car battery. Book a free battery check at your local Formula One Autocentres branch, and our battery technician can diagnose the issue. If you are unsure about what battery you need for your vehicle, contact our team today.