Alternator not charging — signs and possible causes
The alternator charges the battery and powers the car's electrics while driving. If it stops charging, the car runs on battery reserve for a while until it runs out — often at the worst moment.
Possible causes
- Worn or loose alternator belt
- Faulty voltage regulator
- Worn alternator brushes
- Damaged wire or corroded connection in the charging circuit
What you can safely check yourself
- Whether the battery warning light is on while driving
- Whether headlights and interior lights get dimmer
- Whether you hear a squeal from the engine bay (belt)
When to call a mechanic
If the battery light is on, switch off non-essential electrics and avoid long drives. If it comes on together with a temperature warning, stop somewhere safe — the belt may also drive the water pump.
How MobilaisServiss can help
We measure the charging voltage with the engine running, check the belt, regulator and connections, and agree the repair or replacement.
This is a general guide, not a diagnosis. The exact cause can only be confirmed after inspecting the car.