Quote Originally Posted by aaronng View Post
If your revs are low, then you are not producing as much juice from the alternator, hence the battery having to bear the brunt of the current draw and the voltage will drop slightly.
I think the reading is taken from the ECU.

I thought taking the battery voltage under certain conditions was a way of testing your battery/alternator. I haven't found information on the Euro but I've found information on other cars and the numbers seem very similar.

Voltage with car off approx 12V. Mine 12.1

Voltage with car on at idle, no electric load 14V. Mine 14.1

Voltage at idle with full electric load not less than 12V otherwise could be battery/alternator problem. Mine did show a reading as low as 11.6V