Battery light on while driving: what it means

Critical warning

The charging system, usually the alternator, is no longer keeping the battery charged. Cut your electrical use and drive only as far as you need to reach a safe place or a repair shop.

Can you keep driving?

A short distance, using as little electrical power as possible. Drive straight to a safe place or a repair shop, and do not switch the engine off until you arrive.

Car battery and an alternator standing side by side on a workshop bench

What the warning actually means

The symbol looks like a battery. It does not mean the battery is bad. It means the battery is not being charged while the engine runs, so the car is running on stored power, and stored power runs out.

Common causes

  • A failing alternator
  • A broken or slipping drive belt
  • A poor connection or corroded battery terminals
Battery and alternator sitting side by side in an engine bay
A failing alternator or a slipping drive belt are the usual reasons the charging stops.

What to do now

  1. Switch off what you do not need: radio, air conditioning, heated seats.
  2. Drive straight to a safe place or a repair shop.
  3. Do not switch the engine off until you arrive. It may not restart.
View over the steering wheel of a car being driven on a road at night
Every light and fan now runs on stored power, so switch off what you do not need.

What people often get wrong

That the battery itself is the problem. The light says the battery is not being charged, and that is usually the alternator or the belt. A new battery fixes nothing if the charging is missing.

When the car must go to a workshop

The car should be seen the same day. How long the engine keeps running varies from a few minutes to considerably longer, depending on the battery and the electrical load.

Read next

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.

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