Is my car battery dead? Nine signs

1. The starter turns, but the engine does not start

A starter that cranks slowly or turns a few times and stops points to a flat battery. If it cranks at normal speed, the problem may be spark or fuel.

2. Nothing happens when you turn the key

No lights, no sound. Could also be the ignition switch, a fusible link or the starter.

3. The radio and headlights will not switch on

Dim or dead lights with a car that will not start usually mean a dead battery, but could be a corroded connection or a blown main fuse.

4. No door chime or dome light

A weak battery gives a dim dome light. A completely dead one gives none, though a faulty fuse or door switch can do the same.

5. Weak electrics while running

The alternator recharges the battery as you drive and powers the electrics. Weak power is most noticeable in cold weather when heaters and lights work harder.

6. A jump start every morning, fine later

It may be a parasitic drain: something left running overnight draining the battery.

7. A poor response to temperature

Cold slows the starter, and a battery with higher cold cranking amps may be needed. High heat can speed up corrosion inside the battery.

8. A warning light on the dashboard

A battery or check engine light can mean a loose terminal, damaged cables or a problem with the charging system.

9. Could it be the alternator?

If the battery light stays on while you drive, the alternator or its belt may be failing. A faulty alternator can overheat and damage the battery.

Jump-starting can be risky, and in the worst case a battery can explode, so take care, and if in doubt ask a trained mechanic.

Every time a battery goes flat it takes some irreversible damage, so a battery that has been repeatedly jump-started or recharged from flat will need replacing. Even a healthy battery has a limited number of charge cycles, and most need replacing every three to five years.

If the voltage drops below about 10.5 volts, the plates become coated in lead sulfate, which can form crystals that a charger cannot remove. At that point the battery has to be replaced.

Find the cause before you replace or recharge: a faulty charging system can leave you stranded again. If your alternator is being repaired, ask whether the battery needs replacing too. We fit batteries where you are, and can test them on the spot. See our services, or call us.