Electrolyte Level, Checking (Batteries With Charge Indicator)
Electrolyte Level, Checking (Batteries With Charge Indicator)
Special tools, testers and auxiliary items needed
- VAS 5045 Battery filling bottle (or equivalent)
WARNING:
- Refer to Warnings and Safety Measures.
- When checking electrolyte level with sealing caps removed, illuminate the inside of the battery housing/cells with a flashlight.
- Keep open flames and sparks away.
The correct battery electrolyte specific gravity is an important factor in maintaining battery performance and service life.
Insufficient electrolyte levels allow cell plates to dry, resulting in a loss of battery capacity (reduced output). If the cell plates are not completely submerged by electrolyte, (sulfuric acid/water mixture) corrosion will occur on the plates, plate bridges and cell connector. Optimum battery function is not possible under these conditions and battery failure results.
If electrolyte level is too high, electrolyte (sulfuric acid/water mixture) may leak out and damage the surrounding area, i.e.: plenum and engine compartment.
CAUTION: Before beginning repairs on the electrical system
- Switch off all electrical consumers.
- Switch ignition off and remove ignition key.
- Check electrolyte level visually, either via charge indicator (if equipped) or from min./max. markings on battery housing.
Electrolyte level reading from charge indicator -arrow-.
- Green -> electrolyte level OK
- Colorless or yellow -> critically low electrolyte level. Top up with distilled water immediately
CAUTION: Do not use charge indicator to determine excessive electrolyte levels. Always check for excessive electrolyte levels visually.
Electrolyte level reading from min./max. marking on battery housing -arrow-.
- Electrolyte level must be above the minimum marking or just reach the maximum marking.
If no minimum and maximum markings are visible on the battery housing (either not molded-in or not visible due to installation location) or if the battery housing is black, the sealing plugs must be removed. Then determine electrolyte level by viewing inside the battery cells.
- First remove plastic foil from cell caps, being sure not to disturb plastic safety warning label on battery.
- Unscrew cell caps -2-.
- Look into individual battery cells to determine electrolyte level.
- Electrolyte level must align with the internal electrolyte level indicator (lip) -1-. This equates to the external "maximum" marking on the battery case.
NOTE: On batteries with black housings, obtain accurate electrolyte level readings by illuminating inside of cells with a flashlight.
Electrolyte level too low
Electrolyte level too high
No load voltage, checking Testing and Inspection
Load test Testing and Inspection
Electrolyte level too low
- Fill with distilled water using battery filling bottle VAS 5045 (or equivalent) up to the max. marking
NOTE: Design of filler support on filling bottle VAS 5045 prevents overfilling of battery cells and subsequent electrolyte leaks. When max. level is reached the flow of distilled water into battery cells stops.
CAUTION:
- Only use distilled water to top-up batteries. This prevents electrolyte impurities which cause self discharging.
- DO NOT overfill the battery
- Overfilled batteries can boil over.
- Too little electrolyte reduces the service life of the battery.
- Use use of genuine VW battery cell caps ensures the different battery cover systems are sealed correctly. Only use genuine cell caps of the same construction if lost or damaged. All cell caps must be equipped with an O-ring seal.
Electrolyte level too high
Special tools, testers and auxiliary items needed
- Commercially available hydrometer
WARNING:
- Refer to Warnings and Safety Measures.
- If electrolyte level is too high, electrolyte (sulfuric acid/water mixture) may leak out and damage the surrounding area, i.e.: plenum and engine compartment.
- Excess electrolyte MUST be extracted using a hydrometer
- Dispose of electrolyte (sulfuric acid) properly! Waste electrolyte must only be disposed of in appropriate waste disposal sites. Refer to local regulations pertaining to electrolyte disposal.
- Remove cell caps from cells with excess electrolyte.
- Extract excess electrolyte using hydrometer until electrolyte level is lowered to internal level indicator -1- or external maximum marking.
CAUTION: Use use of genuine VW battery cell caps ensures the different battery cover systems are sealed correctly. Only use genuine cell caps of the same construction if lost or damaged. All cell caps must be equipped with an O-ring seal.