Measuring No Load Voltage

Measuring No Load Voltage

Special tools, testers and auxiliary items required

• Hand-Held Multimeter (V.A.G 1526E)

Maintenance-free batteries must not be opened. Otherwise, the warranty is voided.


It is not possible to check the battery using "Guided Fault Finding" during the following procedure, even if the vehicle has a battery monitoring control module (J367) :

• Audi A3 from MY 04 (8P)

• Audi TT from My 07 (8J)

• Audi R8 from MY 07 (42)

• Measuring the no-load voltage, for example, during the prescribed maintenance and service work on vehicles in storage, determines whether the battery must be recharged.

Procedure

To ensure a correct measurement, the following points must be followed.

• Battery must not be loaded by electrical consumers within the next 2 hours before measurement.

• After battery charging or engine operation, the measurement can be performed only after a 12 hour waiting period.

• The battery temperature must be at least 10° C (50 °F).

After a waiting period of at least 12 hours:

- Measure the voltage between the battery terminal clamps.

• Specified value: 12.5 volts or higher, the battery is OK.

- If the no-load voltage is under 12.5 volts, the battery must be recharged. Refer to=> [ Charging The Battery Using ] Charging The Battery Using (VAS 5903).

- After charging for 5 minutes, the current draw must be measured again. Refer to=> [ Current Draw Test ] Current Draw Test.

- If the battery no-load voltage is 11.6 volts or lower, the battery is exhaustively discharged.