Battery Inspection, Maintenance and Charging

GENERAL INFORMATION

Tools and materials required for battery maintenance 1 Face shield/safety goggles – when removing corrosion with a brush, crystallized acid particles can easily get into the eyes 2 Baking soda – an aqueous baking soda solution can be used to neutralize corrosion 3 Acid-free petroleum jelly – a layer applied to the battery terminals helps prevent corrosion 4 Terminal/cable clamp cleaning tool – this tool with a wire brush removes all corrosion from battery terminals and cable clamps 5 Impregnated felt washers – installing these washers on each battery terminal directly under the cable clamps helps prevent corrosion 6 Puller – cable clamps can sometimes be very difficult to remove from the battery terminals, even after the nuts/bolts are fully loosened. This tool allows the clamps to be pulled straight up without damage 7 Terminal/cable clamp cleaning tool – another type of cleaning tool, a slightly modified version of item 4 with the same function 8 Rubber gloves – another means of protection when working with the battery; remember that the battery contains acid!

Battery fuse box 1 “–” terminal 2 Nut 3 Positive cable mounting bolt, do not loosen 4 Fuses

Inspection and Maintenance

CAUTION

Observe certain safety precautions when working with the battery. The battery cells always contain highly flammable hydrogen gas, so never bring a lit cigarette or other open flame near the battery. The battery electrolyte is a solution of sulfuric acid, which causes serious injury if it contacts the eyes or exposed skin. The acid also damages clothing and paint. When disconnecting the battery, always disconnect the negative cable first and connect it last!

PROCEDURE

1. Battery maintenance is a very important procedure that helps prevent breakdowns on the road due to battery discharge. Several tools are required to perform the maintenance procedure.

2. Before starting any maintenance procedure, always first switch off the engine and turn off all electrical consumers, then disconnect the negative cable from the battery.

CAUTION

If your vehicle radio is equipped with an anti-theft system, make sure you have the correct code before disconnecting the battery.

3. AUDI vehicles are usually equipped with batteries that require little maintenance. The cell caps can be removed and distilled water added. Recent models may be equipped with fully sealed maintenance-free batteries.

4. The center fuses are covered by the main fuse box. To remove the main fuse box, disconnect the battery ground cable (-).

CAUTION

This erases the data stored in electronic memory modules, such as the radio code. Read the instructions in the section Entering the Radio Code.

5. Unscrew hex nut -2- and release the bracket of the main fuse box from the battery housing.

6. Remove the caps and check the electrolyte level in each battery cell. It must be above the plates. Each cell usually has a level indicator. If the electrolyte level is below normal, add distilled water only, then close the cell caps.

CAUTION

Overfilling the cells may cause electrolyte to spill out during rapid charging, causing corrosion and damage to components near the battery.

7. If the positive terminal and battery cable clamp of your vehicle are fitted with a rubber protector, make sure it is not torn or damaged. It must fully cover the terminal.

8. Periodically inspect the battery exterior for damage such as cracks in the housing.

9. Check that the battery cable clamps are tight enough to ensure good electrical contact. Inspect each cable along its entire length for cracks and worn insulation.

Battery terminal corrosion usually appears as a light, loose powder

Disconnecting the cable from the battery terminal with a wrench – sometimes, when corrosion has damaged the nut, special pliers are required for this procedure (always disconnect the ground cable first and connect it last!)

Regardless of the type of cleaning tool used, the result must always be a clean, shiny terminal surface

When cleaning cable ends, remove all traces of corrosion (the inside of the cable end is tapered to match the battery terminal shape, so do not remove too much material)

10. If corrosion is found (usually a loose white deposit), disconnect the cables from the terminals, clean them with a special brush, and reconnect them. Corrosion can be minimized by installing specially treated washers, available from auto parts stores, or by applying a layer of acid-free petroleum jelly or suitable grease to the terminals and cable clamps after connecting them.

11. Make sure the battery tray is in satisfactory condition and the clamp bolt is securely tightened. If the battery has been removed from the tray, make sure no parts or other foreign objects are left on it during installation. When clamping the hold-down clamp, do not overtighten its bolt.

12. Corrosion deposits on the tray, battery case and surrounding surfaces can be removed with a solution of baking soda in water. Apply the mixture with a small brush, let it stand, and then rinse off with plenty of clean water.

13. Corroded metal surfaces of the vehicle should be coated with zinc-based primer and then painted. Charging

CAUTION

The manufacturer recommends removing the battery from the vehicle for charging, because gas released during this process can damage painted surfaces or the vehicle interior, depending on the battery location. Rapid charging with the battery cables connected may damage the vehicle's electrical system.

14. Remove all cell caps from the battery (if equipped) and cover the openings with clean rags to prevent electrolyte splashing. Disconnect the negative battery cable and connect the charger leads to the battery terminals (positive to positive, negative to negative), then plug the charger into the mains. If the charger has a switch, make sure it is set to the "12 volt" position.

CAUTION

If your vehicle radio is equipped with an anti-theft system, make sure you have the correct code before disconnecting the battery.

15. If you use a charger with a current above two amperes, check the battery regularly during charging to make sure it is not overheating. When using a slow charger, you may leave the battery to charge overnight after regular checks during the first two hours. When charging maintenance-free batteries, certain precautions may be required (for example, using a very low-amperage charger). Such a battery may have a warning label; if there is none, consult an AUDI dealership or an automotive electrician.

16. If the battery cells have removable caps, check the electrolyte specific gravity with a hydrometer every hour during the final few hours of the charging cycle. Inexpensive hydrometers are sold in auto parts stores; follow the instructions supplied with them. The battery can be considered charged if the specific gravity readings do not change over two hours and the electrolyte in the cells bubbles freely. The specific gravity in individual cells should be nearly the same. If it is not, one or more cells have failed and the battery should be replaced.

17. Some maintenance-free batteries have a built-in hydrometer with a window on top, serving as a color indicator of the battery state of charge. Normally, a bright-colored window means the battery is fully charged, while a dark color indicates that additional charging is required. For more precise information, refer to the battery manufacturer's instructions.

18. If the battery is sealed and has no built-in hydrometer, you can check the state of charge using a digital voltmeter connected to the battery terminals. A fully charged battery will show 12.6 volts or more.