Battery Inspection

GENERAL INFORMATION

Electrolyte Level Inspection

Distilled water may be required to perform this work.

For standard batteries, once the electrolyte has been filled, under normal conditions it is sufficient for the entire service life of the battery. However, at high outside temperatures and after charging the battery, as well as during maintenance, the electrolyte level must be checked.

PROCEDURE

1. The battery is located in the engine compartment. Open the battery cover by releasing the clips and press the cover down.

2. Check the electrolyte level from the outside through the transparent battery case. If the electrolyte level in any cell has dropped below the MIN mark, remove the cap.

CAUTION

If the electrolyte level cannot be determined, remove the cap and look into the battery. Do not use an open flame. Risk of explosion!

3. The center caps are covered by the fuse box. To remove the box, squeeze the tabs and swing the cover open.

4. Disconnect the negative (–) battery cable with the ignition switched off.

CAUTION

As a result, data is erased from electronic memory modules, such as the radio code. Without the code, the radio can only be activated by the manufacturer or at an AUDI authorized service station. Therefore, read the notes in the subsection Removing and Installing the Battery.

5. As a result, information is erased from the electronic memory modules, such as the radio code. Without the code, the radio can only be activated by the manufacturer or at an AUDI service station. Therefore, refer to the notes in the subsection Removal and Installation of Battery.

6. Fill each cell separately with distilled water up to the MAX mark.

7. Install and tighten the plug.

8. Install the main fuse block and secure it with nut -2-.

9. Finally, charge the battery. Refer to the subsection Battery Condition Check, Care and Charging.

10. If a battery fault is suspected, measure the open-circuit voltage. Refer to the following subsection.

11. Connect the negative cable (–) to the battery.

CAUTION

Activate the power window safety automatic function, enter the radio code, and set the clock. Refer to the section Automatic Transmission and Models with All-Wheel Drive.

12. Secure the battery cover with the clamps. Checking Battery Terminal and Holder Attachment

CAUTION

If the battery is loosely secured or the terminals are not connected, this may result in premature battery failure due to vibration, cable fire, or malfunction of electrical equipment. Since data in electronic memory modules, such as the radio, is erased when the battery is disconnected, read the subsection Removing and Installing the Battery and the subsection Entering the Radio Code.

PROCEDURE

1. Move the battery terminals in opposite directions and check that they are secure. Tighten if necessary.

2. If the battery is loose, tighten the mounting bolt to 20 N·m. Checking Open-Circuit Voltage

The battery condition is checked by measuring voltage with a voltmeter connected between the battery terminals.

PROCEDURE

1. Disconnect the battery. Refer to the subsection Removal and Installation of Battery.

2. The battery must be disconnected for 2 hours before testing.

3. Connect the voltmeter to the battery terminals and measure the voltage.

4. Evaluate the voltage:

12.5 V or more – battery is in good condition. 12.4 V or less – battery is in poor condition; it must be charged or replaced with a new one.

5. Connect the negative cable (–).

CAUTION

Activate the power window automatic function, set the clock, and enter the radio code. Refer to the subsection Removing and Installing the Battery and the subsection Entering the Radio Code.

Checking Battery Under Load

PROCEDURE

1. Connect a voltmeter to the battery terminals.

2. Start the engine and check the voltage.

3. When starting the engine with a fully charged battery, voltage must not drop below 10 V (electrolyte temperature approx. +20°C).

4. If the voltage drops sharply and the electrolyte density differs between cells, the battery is damaged and must be replaced. Checking Electrolyte Density

Electrolyte density, together with voltage, gives an accurate indication of the battery state of charge. A hydrometer is used to check electrolyte density. When testing the battery, electrolyte temperature must be at least +10°C.

PROCEDURE

1. Switch off the ignition.

2. Remove all plugs from the battery. If there is a cover, remove it first with a screwdriver.

3. Insert the hydrometer into one of the cells and draw in enough electrolyte to float the float. The higher the specific gravity (density) of the electrolyte, the higher the float rises. The scale shows electrolyte density in specific gravity units (g/ml) or in degrees Baumé (°Bé).

4. Electrolyte density must be at least 1.24 g/ml – refer to Specifications. If density is low, the battery must be charged.

5. Check each cell in turn. All cells must have the same density (maximum difference 0.04 g/ml). If the difference is greater, the battery is faulty. Battery Charging

CAUTION

Before charging the battery, read the safety notes in the subsection Removing and Installing the Battery.

PROCEDURE

1. Do not disconnect the battery with the engine running.

2. Never short-circuit the battery, i.e. do not connect the positive (+) and negative (–) terminals. This causes the battery to overheat and may crack.

3. Do not use an open flame near the battery. Electrolyte is poisonous. Keep it away from eyes, skin and clothing. If contact occurs, flush thoroughly with water.

4. On batteries with a central gas vent, do not remove the plugs (cross-head slot) during charging.

5. Before charging a frozen battery, allow it to thaw. A fully charged battery freezes at about -65°C, a half-charged battery at about -30°C and a discharged battery at about -12°C. After thawing, check the battery for cracks. Replace if necessary.

6. When charging the battery with a standard charger or fast charger, remove the battery. At minimum, disconnect the negative (–) and positive (+) cables.

When using a portable charger (low current), charging can be carried out without removing the battery. The connecting cable to the vehicle electrical system does not need to be disconnected. Battery manufacturer's data must of course be taken into account. Charging

PROCEDURE

1. Disconnect the battery.

2. Check the electrolyte level. If necessary, top up with distilled water. Refer to the relevant section.

3. Charge the battery only in a well-ventilated area or outdoors. When charging the battery without removing it from the vehicle, open the hood.

4. Check that the gas vent hose is not pinched and the gas vent nozzle is not clogged.

5. If the fast charger allows current adjustment, set the charging current to 10 % of battery capacity, i.e. for 50 Ah capacity set the current to about 5 A. Charging time can be taken as 10 hours.

6. With the charger switched off, connect the positive (+) cable of the charger to the positive (+) battery terminal. Connect the negative (–) charger cable to the negative (–) battery terminal.

7. Plug the charger into a mains socket. If necessary, switch on the charger.

8. If the battery is charged with direct current, check the battery temperature by placing your hand on it. Electrolyte temperature during charging must not exceed +55°C. Otherwise, interrupt charging or reduce the charging current.

9. After charging, switch off the charger (if possible) and unplug it from the mains.

10. Disconnect the charger cable from the battery.

11. Check the battery charge. Refer to the subsection Battery Condition Check, Care and Charging.

12. Install the battery. Refer to the relevant section. Notes for Batteries with Plugs

PROCEDURE

1. Before charging, remove the battery vent caps, or use a thin screwdriver to lift the cover slightly and leave the vent openings partially closed. This prevents electrolyte from spraying out due to gas formation.

2. Continue charging until all cells are gassing freely and the voltage and electrolyte specific gravity do not change over three consecutive measurements taken three hours apart.

3. After charging is complete, allow the battery to vent for 20 minutes. Then install the vent caps. Charging a Deeply Discharged and Sulfated Battery

A battery that has not been used for a long time (for example, during extended vehicle storage) will discharge and become sulfated over time. If the open-circuit voltage of the battery is below 11.6 V, the battery is considered deeply discharged. Check the resting voltage. In a deeply discharged battery, the electrolyte consists almost entirely of water.

CAUTION

At sub-zero temperatures such a battery may freeze and the case may crack. A deeply discharged battery sulfates, i.e. large, poorly soluble lead sulfate crystals form on the electrode surfaces. The electrolyte then loses its clarity and takes on a faint white color. If a deeply discharged battery is charged immediately after discharge, sulfation occurs again. Otherwise the battery plates continue to harden, and the possibility of charging the battery for an extended time remains limited. A deeply discharged and sulfated battery must be charged with a reduced current of about 5 % of capacity, i.e. for a 60 Ah battery the charging current must be 3 A. The charging voltage must not exceed 14.4 V. Never charge a deeply discharged battery with a rapid charger.

Boost Charging/Jump Starting

PROCEDURE

1. Use a boost charger only to start the vehicle. The charging current must be 20% or more of the battery capacity. This damages the battery, as it is exposed to high currents. Do not charge a battery that has been unused for a long time or is deeply discharged with a boost charger, as this causes sulfation. Battery Storage

2. If the vehicle has not been used for more than two months, remove the battery and charge it. The optimum battery storage temperature is from 0 to +27°C. At these temperatures, battery self-discharge is minimal. Charge the battery at least once every two months, otherwise it will become unserviceable.

A battery that has not been used for a long time (for example, a vehicle that has not been driven) will discharge and may also become sulfated. If such a battery is charged with a boost charger, it either does not accept the charging current or becomes "fully" charged far too quickly due to sulfation. In fact, the battery is damaged.

Before determining that the battery is damaged, check the following:

3. Electrolyte specific gravity. If the difference in specific gravity between individual cells does not exceed 0.04 g/ml, charge the battery with a normal battery charger.

4. After charging, test the battery under load. If the battery performance is below the values given in the Specifications, the battery is damaged.

5. If the electrolyte specific gravity in one or two adjacent cells differs noticeably (for example, 1.16 g/ml in five cells and 1.08 g/ml in the sixth), the battery has an internal short circuit and must be replaced.