Battery handling warnings
The battery is located in the engine compartment, in the water box.

CAUTION!
- Work on the battery and electrical system carries risks of injury, burns, accidents and fire.
- Before working on the electrical system, switch off all electrical consumers and remove the ignition key. Disconnect the negative battery cable. To replace a bulb, switch off the lights.
Warning!
- Never disconnect the battery from the vehicle while the ignition is switched on or the engine is running. The electrical equipment or electronic components would be damaged.
- Do not expose the battery directly to daylight for prolonged periods, in order to protect the battery case from UV rays.
Charging the battery
A charged battery is essential for good engine starting performance.
- Read the warnings in the chapter "Battery handling warnings", and
- Switch off the ignition and all power consumers.
- Only for "rapid charging": disconnect both connecting cables (first the "negative" cable, then the "positive" cable).
- Connect the charger clamps to the battery terminals according to the charger manufacturer's instructions (red = "positive terminal", black or brown = "negative terminal").
- After this, plug the charger power cable into the mains socket and switch on the charger.
- At the end of the charging process: switch off the charger and unplug the power cable from the mains socket.
- Then remove the charger clamps from the battery.
- If necessary, reconnect the battery cables (first the "positive" cable, then the "negative" cable).
Normally it is not necessary to disconnect the connecting cables from the vehicle electrical system when charging the battery with a low current (e.g. with a small charger).
Before charging with a high current, i.e. for "rapid charging", however, you must disconnect both
battery connection cables. Always follow the charger manufacturer's instructions,
Rapid charging of a battery is dangerous => see Chapter
"Warnings for handling batteries". This procedure requires a special charger and specialist knowledge. We therefore recommend having your battery rapid-charged only by a specialist workshop.
A discharged battery can freeze at 0 °C. Before charging, a frozen battery must be thawed. => A- However, we recommend not reusing a thawed battery if possible, as the battery case may be cracked by ice and electrolyte may leak out.
Do not open the battery caps while charging.
CAUTION!
Never charge a frozen battery - risk of explosion!
Test yourself
A quick Audi A4 quiz: every answer comes with an explanation and a link to the manual page.