The electrolyte, which is a mixture of sulfuric acid and distilled water, can lose water at high temperatures or if the voltage regulator is faulty. Water loss can also occur due to self-discharge of the battery (for example, during prolonged downtime) or deep discharge due to a powerful current consumer not being switched off. In this case, you should add distilled water. Tap water, as well as boiled water, contains conductive salts and other minerals that are harmful to the battery.
1. When working with the battery, follow the warnings that are accompanied by the following pictograms: "Caution, acid!", "Wear protective glasses!", "Do not use open flame!", "Caution, detonating gas!". When disposing of the battery, it is necessary to follow the rules for handling batteries and sulfuric acid.
There are marks on the side of the battery to control the electrolyte level.
2. The electrolyte should reach at least the minimum mark (the electrolyte should cover the upper edges of the plates). The electrolysis level must be maintained so that it reaches the maximum mark. Control is greatly facilitated in batteries with a "magic eye" (see picture). The viewing window indicates an unsatisfactory battery condition: low electrolyte level or battery discharge. The indication may be distorted due to air bubbles. Lightly tap the peephole! When the battery is in normal condition, the indication is green. If the indicator is yellow or there is no color, it is necessary to add distilled water, as this means that the critical electrolyte level has been reached. If the indicator is black, the battery needs to be recharged or charged.
If the battery life exceeds five years and there is no color in the magic eye, then the battery needs to be replaced with a new one.
The magic eye (arrow) in the battery informs about the electrolyte level and the state of charge of the battery
3. If the electrolyte level is low, remove the film over the plugs and unscrew the plugs. When adding distilled water, Audi recommends using the VAS 5045 filling device.
Filling device VAS 5045 for adding distilled water (recommended by Audi). The filling nipple prevents the battery from overfilling and electrolyte from spilling.
4. If the battery is charged, fill it with distilled water up to the maximum mark (15 mm above the top edges of the plates).
5. If the battery is very discharged, add enough water so that the electrolyte just covers the plates. When charging, the electrolyte level rises significantly. After charging the battery, add water to the upper mark. If the element plates are not completely covered with electrolyte, the plates and jumpers are subject to corrosion. This causes damage to the battery, it may become unusable.
Densimeter with a pipette for sucking out excess electrolyte from the battery
6. However, the battery should not be overfilled, otherwise the electrolyte will start to leak out through the plugs or the side ventilation hole. This leads to the formation of corrosion and acid crystals on the surface of the battery and the parts located in the engine compartment. For this reason, the excess electrolyte should be sucked out using a densimeter with a pipette.
7. Suck out the electrolyte until the electrolyte level reaches the plastic jumper or the maximum mark. Screw in the plugs.
Contact care
1. Remove oxide crystals on the battery terminals using warm soda water or a special product called Neutralon (manufactured by Varta).
2. Recently, Audi has been requiring that battery terminals not be lubricated.
3. To avoid damage, the pole clamps must be connected manually and without force. The tightening torque for the pole clamps is 6 Nm.