Important safety warnings for handling a car batteryImportant safety warnings for handling a car 
battery  - Battery - Checking and topping up fluids - General maintenance - Audi S5 Owner's Manual - Audi S5

All work on batteries requires specialist knowledge.

The vehicle battery is located under the floor panel in the luggage compartment.


Always be aware of the danger of injury and chemical burns as well as the risk of accident or fire when working on the battery and the electrical system.
Wear safety glasses. Do not allow acid or lead particles to come into contact with eyes, skin or clothing.
Battery acid is extremely corrosive. Wear protective gloves and safety glasses. Do not tilt the battery - acid can leak out of the vapour vent. If electrolyte should splash into the eyes rinse at once for several minutes using clear water. Then seek medical care immediately. Neutralize any acid splashes on the skin or clothing with soap solution, and rinse off with plenty of water. If acid is swallowed by mistake, consult a doctor immediately.
Keep open flames, sparks, uncovered lights and lit cigarettes away from battery. Avoid sparks (including those from static charges) when handling cables and electrical equipment. Never cross the battery poles. The resulting high-energy sparks can cause injury.
A highly explosive mixture of gases is given off when the battery is under charge. Only charge battery in a well ventilated area.
Keep children away from the battery and battery acid.
Switch off all electrical equipment before starting any work on the vehicle electrical system. Remove the ignition key. The minus cable of the battery must be disconnected. When changing a light bulb, it is sufficient to only turn off the light.
Before disconnecting the battery, turn off the anti-theft system! Otherwise, the alarm will sound.
When disconnecting the battery from the vehicle's electrical system, first disconnect the minus cable and then the plus cable.
Before reconnecting the battery, turn off all electrical equipment.
First connect the plus cable, then the minus cable. The battery cables must not be connected to the wrong battery poles - serious risk of cable fire.
Never charge a frozen or thawed out battery - risk of explosion and chemical burns! A battery must be replaced once it has been frozen. When it is discharged the battery can freeze at temperatures around 0C.
Make sure that the vapour hose is always attached to the battery.
Never use a damaged battery - risk of explosion! Replace a damaged battery immediately.

Never disconnect the car's battery with the engine running or with the ignition turned on, otherwise the electrical system or electrical components will be damaged.
Do not expose the battery to direct sunlight over a long period of time, as the intense ultraviolet radiation can affect the battery housing.
If the car is left standing for long periods, protect the battery from extreme cold temperature so that it does not freeze up and become damaged.