Checking electrolyte level — AUDI

Warning
When using battery electrolyte it is absolutely necessary to adhere to the accident prevention procedures.
Suitable protective clothing must be worn.
Only use a battery-powered lamp to illuminate the inside of the battery housing.
Never illuminate the inside of a battery housing with an open flame.
Never work with an open flame or burning cigarette in the vicinity of a battery.
Ensure the legislation for the disposal of batteries and sulphuric acid is observed when disposing of batteries.
It is essential that sealing plugs supplied with the battery be used to ensure that differing battery cover systems are sealed correctly. Only use genuine sealing plugs of same type if lost or damaged.
The plugs must be fitted with an O-ring seal.
Special tools and workshop equipment required

Battery filler bottle VAS 5045
Commercially available hydrometer

Notes:

The correct battery electrolyte level is an important factor in ensuring the long life of the battery.
Batteries with visible min. and max. markings require only a visual check of electrolyte level from the battery exterior.
The electrolyte level must be above the minimum marking but not exceed the max. marking.
The sealing plugs must be unscrewed on batteries if the exterior min. and max. marking are difficult to recognize, or the electrolyte level is not visible due to the opaqueness of the battery housing. It is then possible to check the electrolyte level by performing a visual check of the inner battery.
The electrolyte level must align with the internal electrolyte level marking (horizontal ridge. This equates to the outer max. marking.

On batteries with a condition indicator -arrow-, the electrolyte level can be checked via the colour display => Test sequence, Page
27-6
.

Electrolyte level too low

Note:

If the electrolyte level is too low, the cell plates will dry out and the battery will lose power. The cell plates must be fully covered by the electrolyte (sulphuric acid) in order to prevent corrosion of the plates, plate bridges and cell connectors. Corrosion of these parts will make the battery unreliable and ultimately unusable.

If the electrolyte level is too low, top up with distilled water using battery filler bottle VAS 5045 until the "Max." marking is reached.

Notes:

The neck of filler bottle VAS 5045 is designed to prevent overfilling of the battery cells, which would cause the electrolyte to overflow. When the "Max." level is reached, the flow of distilled water into the battery cell is cut off.
Use distilled water only, this prevents contamination of the battery electrolyte and the therefore associated increased self discharge.

Screw sealing plugs into battery cells
=> Page
27-3
, Batteries with central gas venting

Electrolyte level too high

Note:

If the electrolyte level is too high the leaking electrolyte (sulphuric acid/water mixture) will cause damage outside the battery, i.e. to components in engine compartment.

If the electrolyte level is too high (i.e. above the plastic indicator bar inside the battery or above the "Max." marking on the outside), the excess fluid must be extracted. This is done using a commercially available hydrometer.
Extract the electrolyte using the hydrometer until the electrolyte level reaches the plastic bar or the max. marking.
Screw sealing plugs into battery cells
=> Page
27-3
, Batteries with central gas venting