Seven signs it is time to replace your car battery

A starter battery lasts three to five years on average. The exact life depends on how the car is driven, on the climate and on the state of the electrical system. Here is what to watch.

1. The starter turns more slowly than it used to

The most honest sign. It shows up best on the first cold start of the morning: the engine does not catch straight away and you can hear the starter labouring.

2. The car will not start after a frosty night

If everything is fine in the warmth of the afternoon but the morning start is hard, the battery has lost part of its cranking current.

3. Headlights dim noticeably at idle

A voltage sag when heavy consumers switch on means the battery no longer holds the load.

4. The car stands for a few days and goes flat

A healthy battery takes a week of standing in its stride. If cranking is weak after two or three days, it is either self-discharge or a parasitic drain in the wiring — both need checking.

5. The case has swollen

Bulging sides are the result of overcharging or of the electrolyte freezing. Such a battery has to be replaced, no options.

6. White or greenish deposit on the terminals

Oxidation itself is cured by cleaning, but if it comes back quickly there is either electrolyte seepage or a poor contact under load.

7. The battery is over four years old

Even if it still starts the car, a battery of that age must be tested before winter. The production date is stamped on the case lid, so the age can be read exactly.

What to do

Testing the battery, the alternator and the parasitic drain is free across the Voltman network and takes a few minutes. If the battery needs replacing, selection, installation and trade-in of the old one are included in the price of the new one.

See also: batteries in winter and how to trade in an old battery.