Warning Signs Your Car Battery Is Failing

A battery almost never dies without notice. For days or weeks beforehand the car behaves a little differently, and drivers who know what to look for can arrange a replacement at a time that suits them.

None of the checks below needs a tool. They need you to notice how the car normally starts and to pay attention when that changes.

Listen to the starter

A healthy battery spins the engine briskly and it fires within a second. As the battery weakens, the starter turns more slowly and the sound drags before the engine catches. You will hear it most clearly on the first start of the morning.

A rapid clicking with no cranking at all means the battery can no longer supply enough current to engage the starter properly. At that stage the next attempt may be the last.

Watch the electrics

The battery symbol on the instrument panel should disappear as soon as the engine runs. If it stays lit or flickers while driving, either the battery or the charging system needs attention.

Other hints are subtler. Headlights that fade at a red light and brighten as you pull away, electric windows that climb slowly, and a start-stop system that has quietly stopped switching the engine off are all signs of low battery voltage.

Look under the bonnet

Find the date code on the battery label or check your last invoice. In this climate, anything older than two years deserves a test whether or not it is misbehaving.

Then look at the case and terminals. Bulging sides point to overheating. A white, blue or green crust around the posts is corrosion, which restricts current and should be cleaned off. A smell of rotten eggs means the battery is venting gas and should be replaced without delay.

If the engine will not start

Stop after two or three attempts. Repeated cranking empties what charge remains and can overheat the starter motor. Turn off the lights, fan and radio, and make sure the car is in Park with the handbrake on.

A jump start will usually get you moving, but treat it as a way to reach help and not as a cure. A battery that has gone flat once without an obvious reason, such as lights left on overnight, will do so again.

What to tell the technician

The fastest call-outs are the ones with clear directions. Send the make, model and year of the car, then the building name, the parking level and the bay or pillar number. In a basement, send the message before you go down, because signal is often lost underground.

Mention whether the car has start-stop, and whether the battery is under the bonnet or in the boot if you know. That lets the right type be loaded on the van before it sets off.