What weakens a battery?

Losing battery power is normal, but there may be other reasons.

The automatic discharge of a battery that is not loaded with any load is called self-discharge. Various factors contribute to this phenomenon, such as contamination of the battery and electrolyte surface or damage to the so-called tile separation. The daily loss of electric charge in a classic lead-acid battery can reach up to 1,5% of its capacity. Manufacturers of new generation batteries limit the degree of self-discharge, incl. by reducing the amount of antimony in lead plates or replacing it with calcium. However, an inactive battery loses its stored electrical charge over time and therefore requires periodic recharging.

The same applies to the battery left in the car for a longer parking. However, in this case, in addition to the phenomenon of self-discharge, large power losses can also be caused by the included receiver. Discharging a battery with a so-called leakage current can also be caused by a malfunction of an electronic device, such as an alarm system.

The battery can also be undercharged while driving due to, for example, a faulty voltage regulator or failure of the generator itself. The risk of insufficient car battery charging also occurs when driving for short distances, especially when driving at low speeds and frequent stops (for example, due to traffic lights or traffic jams). This risk is increased if other receivers such as windshield wipers, fans, heated rear window or radio are used at this time in addition to the mandatory lights.