Battery charge warning light: Everything you need to know

You may not give much thought to your car’s battery whilst you’re out on the road.

However, when the battery charge dashboard warning light appears, it’s important to know what action to take. Ignoring this all-important warning light could cause severe damage to your car’s electrical system.

In this guide, we’ll explain the meaning of the battery charge warning light - and its common triggers. We’ll also guide you through the checks and actions to perform when this light appears, then share some troubleshooting tips.

Finally, we’ll run through the preventative steps you can take to avoid car battery issues.

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What does the battery charge warning light mean?

When the battery charge warning light appears, this means that your battery is no longer being charged by the alternator, and is now only running on its existing charge. Therefore, if left unchecked, your battery will run completely flat, bringing your car to a standstill.

What does a battery charge warning light look like?

The battery charge warning light resembles a large battery with two terminals, one marked with the ‘positive’ symbol (+) - and the other with the ‘negative’ (-).

What causes the battery charge warning light to come on?

Acid corrosion on the battery terminals.
Electrolyte leakage.
Loose or corroded battery cables.
Faulty wiring.
An overloaded electrical system.
The battery may be worn, damaged, or drained. Its cells or plates may also be damaged.
The alternator might not be charging the battery properly.

In simple terms, this light indicates that your car isn’t getting enough current from the battery to run smoothly.

Other signs of battery issues

The battery charge warning light is not the only indicator of battery issues. Car batteries typically last between 3 and 5 years, but can last up to 10 in optimal conditions. When your battery needs replacing, you may notice one or more of the following signs:

Unpleasant odours: If you notice an odd smell coming from the battery, this could mean it is damaged, or there is a leak present.
Jump-starts: If your engine struggles to start and you regularly need to jump-start your car, this is a clear sign that the battery is unable to hold a charge.
Electrical malfunctions: If you notice electrical components such as the windows, lights, and radio malfunctioning, this is symptomatic of a failing battery.
Dim headlights: If your headlights are dimmer than they should be, this may indicate that your battery is deteriorating.

How to troubleshoot your car battery issues

If you have a little mechanical knowledge, you may be able to resolve a minor car battery issue yourself.

Important: Make sure you wear protective gloves whilst inspecting and repairing your battery.

Check for corrosion

During the warmer months, car battery terminals can experience corrosion. Put on a pair of protective gloves. To inspect for corrosion, carefully remove the covers from the terminals on top of your battery. If you see a white or greenish substance, on, or around the terminal, this is indicative of corrosion.
Clean your battery and remove corrosion

Corrosion can stop the battery conducting current to your vehicle’s electrical systems. Luckily, removing corrosion and cleaning your battery is relatively simple. You’ll just need a battery cleaning product (or a homemade solution mixed from water and baking soda).

Make sure the terminal covers are removed. Then, disconnect the battery cable, starting with the negative (black) cable, followed by the positive (red) cable. Using the solution, scrub the battery posts and cable ends until the corrosion has been removed. Next, reconnect your battery by connecting the red cable, followed by the black cable.
Tighten the cable clamps

If you didn’t see evidence of corrosion, the issue may lie with the cable clamps, which connect the battery to your car. Over time, these clamps can become loose, which may cause the battery warning light to appear.

Inspect the cable clamps and make sure they are securely fixed onto the battery terminals. If they are loose, you may be able to tighten them with a standard or socket wrench. However, you should consult your owner’s manual to confirm the manufacturer’s recommended tool and method.
Check your battery charge warning light

If you’ve cleaned your battery, removed any corrosion, and tightened your cable clamps, this should hopefully resolve your battery charge warning light. Start the engine to check whether the light remains.

Next steps if your battery light remains on

If the light persists, you may be dealing with a more complex issue. In this case, we recommend taking your car to a garage for inspection and repairs.

The mechanic will test the battery and its charge level to determine whether it needs to be replaced. The average cost of car battery replacement in the UK is £130, with prices typically ranging from £100-£300.

Battery replacement costs for vehicles with a stop/start system tend to be higher (usually by around 20%).

What should I do if my battery charge warning light comes on when I’m driving?

If the battery charge warning light appears when you’re driving, pull over when it is safe to do so, and investigate the issue:

Stop in a safe location and put on a pair of protective gloves before you investigate the battery.
Check the battery for corrosion and make sure all connections are secure.
Try restarting the engine and see whether the light persists.
If you’re still seeing the warning light, carefully drive to the nearest garage, if you’re able to do so.
If you’re unable to start your car, or it is unsafe to drive, call your breakdown recovery provider to tow your car to the nearest garage.

Steps to prevent battery issues

Keep up with your car’s servicing and maintenance schedule.
Inspect your battery on a regular basis.
Keep the terminals clean and make sure all connections are secure.
Consider using a battery maintainer or a trickle charger. These devices supply a small amount of electricity to your battery when it is unused for an extended period. They may also automatically shut off your battery once it is fully charged to prevent overcharging.

Frequently Asked Questions

If the light has appeared due to a failing alternator, you may only be able to drive for 20 minutes to an hour before power loss brings your car to a halt. However, if the battery is fully charged (and otherwise in good condition), you may be able to drive up to 200 miles on battery power alone.

If you don’t know the exact cause of the warning light, you should visit a garage at the earliest opportunity to avoid getting stranded.

The best way to determine whether you’re dealing with a dead battery or a faulty alternator is to attempt a jump start.

If the car starts, but the engine cuts out quickly afterwards, this may be due to the alternator failing to charge the battery. However, if the car continues running after the jump start, but can’t start again on its own power, a dead battery is the likely culprit.

When the battery charge warning light appears, your car may continue to run on its remaining battery power. However, this will soon deplete, leaving you with a dead battery - and a car that’s unable to start. So, it’s important to visit a mechanic as soon as possible.

Yes, if the battery charge warning light persists during your MOT, your car will automatically fail.

This light indicates an issue with the electrical system, which can compromise your safety - and that of other road users.

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