Car Care: Why do batteries fail in winter?

AA Motoring
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Photo / Supplied

Photo / Supplied

No one likes getting up on a cold, frosty morning. And neither does your car.

Starting your car in the cold may cause it to suffer from hard starting and excessive cranking, which has a huge impact on the motor and electrical system — particularly on the battery.

The inner workings of an automotive battery
Lead acid batteries have been around for eons and they’re the most common car batteries because they're inexpensive and dependable.

These batteries have a plastic case that houses a series of lead plates immersed in a pool of electrolyte — a mix of water and sulphuric acid.

The lead acid battery doesn't produce a charge. It receives and stores an initial charge through a chemical reaction between the cell’s lead plates and the electrolyte.

If a battery is deprived of charge, the positive and negative lead plates are slowly coated with lead sulphate crystals. This process is known as sulphating. 

When this happens, the capacity of the battery drops and it can also lose charge.

If batteries are left too long without a fresh charge, they can discharge beyond recovery.

Why do batteries fail more in winter?
Extreme hot and cold conditions can increase the rate of discharge.

Colder temperatures play havoc on lead acid battery electrolyte, causing it to freeze or thicken, which slows the chemical reaction.

A fully charged battery will be less affected by the cold weather because the electrolyte concentration is higher.

A cold engine with thicker oil can also put extra strain on the battery, needing more power to start .

Keep your battery in top shape with these five tips

●Garage your car
Keeping your vehicle in storage when it’s not being used will protect it from the cold. Starting it will be a lot easier, putting less strain on the battery.

●Ensure the battery is fixed securely
Vibration can cause damage to a battery’s case and plates. Ensure all terminals are cleaned regularly during every major service.

●Keep your battery clean
A clean battery has a longer life. Cleaning your battery cables and terminals regularly will prevent corrosion build-up. If you already have corrosion on your battery, it can easily be removed with water, baking soda and a wire brush. Make sure you disconnect your terminals before getting started. Once the terminals are clean, be sure to wipe with a cloth and cool water. Leaving any baking soda on your battery increases the possibility of more corrosion.

●Listen for early warning sounds
One of the most common signs of a weak battery is a slow cranking when you start the car. If this happens, contact a battery specialist. If the car battery is too weak to provide sufficient voltage to the starter, you'll hear a distinctive clicking sound and the engine won't crank over. The clicking could indicate that the battery is not fully charged and provides a starting point for further diagnostics.

●Check the age of your battery
Older car batteries are more likely to have problems in winter and they’re less likely to recover after going flat. If your battery is more than three years old, it may need replacing.

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