‹
×
Immediate help

Recognizing a faulty car battery: The signs

Das Bild zeigt einen Ausschnitt einer defekten Autobatterie

Even from the outside, you can tell a lot about the condition of a battery. Whether it is still worth recharging the battery or making other rescue attempts. Or whether it is already dangerous and it is better to stay away with the charger.

You can find out how to recognize a faulty battery in this article.
You can also watch the corresponding video here:

Das Bild zeigt die runde, grüne Grafik des Abschnitt 1.

When should a visual inspection of the car battery be carried out?

  • Before charging, carry out a quick check to see whether it is still worth charging or whether it may be dangerous.
  • When used in particularly harsh environments or when exposed to strong vibrations, for example in construction vehicles or agricultural machinery.
  • Otherwise, two to three times a year is generally not a mistake.
  • Always when replacing a battery.

With built-in car batteries, you can often only see the top. Nevertheless, it is always worth taking a look at the box when replacing a battery, as easily recognizable problems provide information on the causes of failure and therefore precautionary measures.

Das Bild zeigt die runde, grüne Grafik des Abschnitt 2.

What should you look out for when visually inspecting a car battery?

Shake the clamps and check that they are tight.
Das Bild zeigt eine Autobatterie an deren Pol mithilfe eines Schraubenschlüssels eine Klemme befestigt wird.

Is there white powder at the terminals? This indicates strong gassing of the battery, sulphate has settled here and electrolyte has been lost.
Das Bild zeigt einen vergrößerten sulfatierten Batteriepol

Has the terminal grown? Is it sitting crooked on the battery? Is it slightly dented at the bottom of the box? Are the terminals still firmly anchored on the battery tray? Loose terminals transmit voltage poorly. The box may already be damaged.
Das Bild zeigt die vergrößerte Darstellung eines verfomten Batteriepols.

Are the labels wavy? The battery was probably exposed to quite high temperatures during operation or charging.
Das Bild zeigt die vergrößerte Darstellung eines abgelösten Batteriettikets.

The box is also deformed by extreme temperatures.
Das Bild zeigt einen verformten Batteriekasten.

Does the box have a crack? A stress crack can be caused by external influences.
Das Bild zeigt einen beschädigten Batteriekasten.

Only for low-maintenance batteries: Remove some acid with the acid siphon. Healthy acid is clear. There is always something wrong with discoloration.
Das Bild zeigt einen Säureprüfer.

Reddish-brown acid indicates sulfation due to deep discharge.
Das Bild zeigt die vergrößerte Darstellung von rötlich verfärbten Stopfen einer Batterie.

Black acid indicates excessively high temperatures. Burnt active mass has been deposited here.
Das Bild zeigt die vergrößerte Darstellung von schwarz verfärbten Stopfen einer Batterie.

Das Bild zeigt die runde, grüne Grafik des Abschnitt 3.

Can the car battery still be saved and how can damage be prevented?

If there are already deposits on the poles or problems with the fit of the poles or the box itself, the only solution is to replace them.

To prevent this, you should regularly:  

  • Tighten the terminals.
  • Tighten the terminals if this is possible on the battery.
  • Recharge the battery properly to avoid deep discharging, overloading the battery and sulphation.
  • Special chargers with boost charging can "revive" sulphated batteries. It is best to contact a workshop for this.
  • Protect the battery from extreme temperatures during charging and operation to avoid gassing, boiling over and thus electrolyte loss.
  • Check the battery box and installation space for stones etc. before installation to prevent damage.
  • And, of course, carry out regular maintenance, i.e. top up with distilled water if this is possible with your battery.

Checking from time to time whether the battery is still there and what it looks like is not a mistake.
Sometimes you can still save it, sometimes it's better to leave it alone. And think carefully about what the battery has to withstand and which one is best suited for the job. 
to the purchase advice for car batteries