Battery Charger :VAS5900 SUPPORT MODE

WARNING: This page is about a different car, the 2023 Audi SQ8, 2023 Audi RS Q8, and 2023 Audi Q8. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Battery Charger:VAS5900

Fig 1: Battery Charger VAS5900
Courtesy of AUDI

General Information

The support mode provides the vehicle electrical system with voltage when the Battery -A- is removed or disconnected.

For more information. Refer to the Battery Charger:VAS5900 Operating Instructions.

The support mode is used for the following situations:

Vehicle electrical system support mode with the Battery -A- not installed
Maintaining the voltage when the battery is being replaced
Systems test without the Battery -A-

WARNING:

Risk of injury. Follow all warning messages and safety precautions. Refer to WARNINGS AND SAFETY PRECAUTIONS .

WARNING:

Do not check or charge a Battery -A- when the visual indicator has >>no color or is bright yellow<<. Jump starting must not be used!

There is a risk of explosion during testing, charging or jump starting.

These Batteries -A- must be replaced.

Procedure

CAUTION:

The polarity protection of the charger clamps is not active in the operation mode "charging severely discharged batteries/Support mode". Connect the charger clamps to the battery terminals correctly according to polarity!
It can result in sparks due to short circuit.
This constitutes an explosion risk.
Do not touch START / STOP button when battery cables are incorrectly connected! The Battery Charger:VAS5900 can become damaged.

-- Remove the Battery -A-. Refer to BATTERY, REMOVING AND INSTALLING .

-- Connect the Battery Charger:VAS5900 to the power supply. The last selected mode is shown on the display. Refer to Battery Charger .

CAUTION:

Whenever the Battery -A- is removed, be careful to prevent contact between the connected charge clamp on the positive terminal and the body ground. Likewise prevent contact between the battery terminals.

-- Connect the red charge terminal (+) to the positive terminal of the Battery -A-.

NOTE:

On vehicles with a Start/Stop function and an installed Battery Monitoring Control Module -J367-, the black charge terminal (-) must be connected to the body ground. The Start/Stop system will malfunction when it is connected to the Battery -A- negative terminal.

-- Connect the black charge terminal (-) to the negative terminal of the Battery -A- /negative connector.

-- Press the START/STOP button for about 5 seconds. The menu selection "Charging severely discharged batteries/Support mode" is activated.

-- Press the corresponding ↑ -button or ↓ button to adjust the battery voltage (6 V/12 V/24 V).

NOTE:

If no button is touched within five seconds, the Battery Charger:VAS5900 will return to the main menu (operating mode selection).

-- Select the battery voltage by pressing the START/STOP button.

Then the inquiry about the correct polarity of the charging clamps is made.

-- Check correct polarity connection of charger clamps.

-- Confirm charging clamps are connected to correct poles via START/STOP button.

The Battery Charger:VAS5900 starts the Battery -A- support mode.

End the Battery Support Mode

-- Press the START/STOP -button.

-- Remove the charging clamps from the battery terminals.

-- Disconnect the Battery Charger:VAS5900 from the power.