Electrolyte Level, Checking

Electrolyte Level, Checking

Special tools, testers and auxiliary items







- Battery filler bottle VAG 5045 (or equivalent)







- Commercially available hydrometer

CAUTION:
- To ensure effective sealing of the various battery cover systems, it is important to use the correct type of battery sealing plugs. If plugs are lost or damaged, always install new plugs of the same type as originally installed.
- Each plug must be installed with an O-ring seal.

NOTE:
- The correct battery electrolyte level is an important factor in ensuring the long life of the battery.
- If the battery has visible "Min." and "Max." markings, the electrolyte level can be checked by a simple visual inspection from the outside.
- The electrolyte level must be above the "Mm"marking and must only reach up to the "Max." marking.
- If the external "Min." and "Max." markings are not clearly visible, or if the electrolyte level is not visible through the battery housing, unscrew the sealing plugs to check the electrolyte level. The level will then be visible inside the battery.
- The electrolyte must be level with the plastic indicator web inside the battery. This corresponds to the "Max." marking on the outside.

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 (sulfuric 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.

NOTE:
- 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 electrolyte impurities, which result in increased self-discharge.
- Screw sealing plugs into battery cells, Batteries with central gas venting.

Electrolyte level too high

NOTE: If the electrolyte level is too high, the leaking electrolyte (sulfuric 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 web 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 electrolyte using the hydrometer until the remaining fluid is level with the plastic indicator web or the "Max." marking.
- Screw sealing plugs into battery cells, Batteries with central gas venting.

Batteries with central gas venting

WARNING:
- Only install batteries of the latest type with central gas venting.
- Always use genuine battery plugs. The plugs must be installed with an O-ring seal.

There are two different types of batteries with central gas venting:

- Batteries WITH hose and hose connection for central gas venting
- Batteries WITHOUT hose and hose connection for central gas venting