Table of contents: Standard battery - test ↓ Maintenance Free Battery - Test ↓
Standard battery - test
1. If the annual mileage of the vehicle is low, check the specific gravity of the electrolyte every three months to determine the condition of the battery. Measure the specific gravity of the electrolyte with a hydrometer and compare the results with the following table. Please note that the specific gravity of the electrolyte is given for a temperature of 15°C. For every 10°C below 15°C, subtract 0.007, and for every 10°C above 15°C, add 0.007. For data on the state of charge of the battery and the specific gravity of the electrolyte in it, see the Specifications.
2. If the battery condition is not exactly known, check the density of the electrolyte in each cell. The difference is 0.040 (or more) between any cells indicates loss of electrolyte or wear of the internal plates.
3. If the difference in electrolyte density in different cells is 0.040 (or more), the battery must be replaced. If this difference is below 0.040, but the battery is discharged, it should be charged as described later in this Chapter.
Maintenance Free Battery - Test
4. In cases where a sealed maintenance-free battery is installed, refilling and checking the density of the electrolyte in each cell is not possible. The battery condition can only be checked using an appropriate indicator or voltmeter.
5. The Delco maintenance-free battery has a built-in charge level indicator. The indicator is located on the top of the battery case and the battery charge level can be determined by its color. If the indicator is green, the battery is fully charged. As the battery discharges, the indicator will become darker and eventually black, indicating that the battery needs to be charged as described later in this Chapter. If the indicator turns light/yellow, the battery electrolyte level is too low and the battery should be replaced. Do not attempt to charge the battery or jump start the engine at this time.
6. To test the battery with a voltmeter, connect the voltmeter to the battery terminals. The results of this measurement will be accurate only if the battery has not been charged in the previous six hours. If this condition has been violated, turn on the headlights and leave them on for 30 seconds. After turning off the headlights, wait 4-5 minutes and take the measurement. All other electrical circuits must be turned off. Make sure that all doors are properly closed.
7. If the measured voltage is less than 12.2 volts, the battery is completely discharged, while a voltage of 12.2-12.4 volts indicates that it is partially discharged.
8. If the battery needs to be charged, remove it from the vehicle (Chapter 3) and perform charging as described later in this Chapter.
Standard Batteries - Charging
Note: The following information is provided as a general guide. Always refer to the manufacturer's recommendations before charging the battery.
9. The battery is charged with a current of 3.5-4 A. Continue charging the battery with this current until an increase in the density of the electrolyte is observed. After four hours from the last increase in density, battery charging can be stopped.
10. Alternatively, charging the battery with a trickle charger at 1.5A can be done safely overnight.
11. Charging too quickly, allowing the battery to be fully recharged within 1-2 hours, is not recommended as it may cause serious damage to the battery plates due to overheating.
12. When charging the battery, ensure that the electrolyte temperature never exceeds 37.8°C.
Maintenance free battery - charging
Note: The following information is provided as a general guide. Always refer to the manufacturer's recommendations before charging the battery.
13. Fully charging this type of battery takes significantly longer (up to three days with significant discharge).
14. A charger that produces constant voltage is required for charging. After connection, the device should be set to a voltage of 13.9-14.9 volts at a current below 25 A. With this charging method, the battery will be ready for use in three hours, producing a voltage of 12.5 volts. This charging period is realistic if the battery is only partially discharged; a full charge requires significantly more time.
15. If the battery is charged from a completely discharged state (voltage below 12.2 volts), have the charging carried out by an Audi/VAG dealer as this process requires constant specialist supervision.