As the weather’s getting colder, how do you know if car batteries are giving up the ghost?

car batteries

Car batteries lead a hard life. And you’re right to be worried. Winter is when batteries are at their most vulnerable.

Battery trouble is the number one reason breakdown companies and garages are called out to cars. Around a fifth of the country’s cars need a new battery every year. How do you tell if your car is one of them? Read on.

How do you know if your car battery is about to die?

When the ignition is turned on, a red battery-shaped light should come on in your car’s instrument panel. This is the car checking that the battery is in working order. If all’s well, the warning light will go out moments after the engine starts.

Sometimes you can tell that the battery is coming to the end of its life because the light stays on for longer than usual. Sometimes the battery can’t supply enough current to turn the engine over as vigorously as it should. On other occasions, particularly after a cold winter’s night, it won’t give the starter motor enough oomph to turn the engine over at all.

What if the battery light comes on while you’re driving?

car batteries

The battery is constantly being charged by a component called the alternator which is powered by the engine. If the alternator stops doing its job, or the battery can’t hold its charge, the light will come on.

You’ll be able keep driving as long as the battery can survive without being charged. Get a garage to check out where the fault lies. If you simply replace the battery and there’s a charging system fault, the new battery will run down almost as quickly as the old one.

How to keep your battery fit

Not giving a battery much charge after starting the engine, is like asking a runner to do another race without have a rest or any food. And if a battery is kept at less than 80% of its charge, the acid in the cells starts to gather at the bottom.

This process is called acid stratification and it prevents the battery holding its charge. To stop this and keep the battery in tip top shape, try to drive for at least 20 minutes once a week to top it up.

When you start your car…

By necessity, car batteries need to be hard wearing. They should live between five and seven years. You can have an impact on that by giving your battery some TLC. Before you’ve got the engine running, don’t turn the headlights on or whack the ventilation fan up to max.

That way the battery will be able to concentrate all its energy on cranking the engine. This is especially important in the winter. Engine oil is thicker in cold weather and it requires more energy from the battery to turn an engine sufficiently for it to fire up.

How to check your battery?

It’s very difficult to know how much life your battery has left in it without specialist equipment. That’s where your garage comes in. Many will check batteries for free.

car batteries

What about charging batteries?

If you don’t use your car a great deal, one way to prevent the battery degrading is to use a charger. Modern smart chargers constantly monitor the battery’s state of charge and provide sufficient power to keep it in tip-top shape. However, some car makers recommend that you don’t charge their batteries and that you use a professional to fit a new one.