I’m often wondering whether I’m the only guy on the forum who owns a Phaeton with the dash panel voltmeter sitting between 13.5 and 14 Volt, instead of a rock solid 14 Volts.
It would be fantastic if some members could provide some feedback of what they are measuring with their VCDS.
The generator performance can be monitored by entering controller 01 (Engine Electronics), then by entering MVB (measuring blocks). Then type 053 in Group A. This will produce the readings of 4 measurements:
Field 1: Engine RPM actual
Field 2: Engine RPM desired
Field 3: Battery Voltage as seen by the Engine ECM
Field 4: Generator power in % (0 to 100)
The latter is the DF value (dynamo field), a value which is reported by the alternator to the J519 module and the ECM. It is the result of the generator's built-in regulator, which controls the power (voltage) output of the generator by means of adjusting the dynamo field current.
It would be very interesting to know what values other forum member are getting for battery voltage and generator power, when RPM is at idle speed (550 RPM), slightly higher RPM (i.e.700 RPM) and at 1500 RPM.
Today I measured these values with VCDS and noticed that the % generator load is constantly sitting at 99.2% at 550 RPM, regardless of consumers. The battery voltage never exceeded 13.58 Volts, even though I shut down every possible power consumer (including the rear heater – via the A/C menu –> extra functions). With electrical consumers, the voltage drops a bit, then slowly recovers to the original 13.58 (except at idle RPM).
The battery voltage stays above 13 Volt most of the time, but occasionally drops down to 12.6 Volts. Increasing engine RPM, does affect the generator load value, but it looks very unstable, sometimes jumping to 0 and anything between 0 and 100.
I made a log file (via the same menu in VCDS) and after I’m done with that, I will post the trends. Meanwhile, I’m anxious to hear what values other members are measuring…Perhaps
what I am seeing is normal behaviour and there is nothing to worry about.