When I go to the engine display the Voltage shows 14.9 to 15V, this is all the time, even after time on the highway. The head of the service advisors at my dealer told me this was normal and the voltage on Mercedes has crept up over the years.


My experience with other vehicles (cars, trucks, airplanes etc.) is that normal alternator voltage is between 13.8 - 14.3V. Anything approaching 15 volts will kill the battery.


Is anyone experiencing voltage this high and if so what does your dealer say about it?


Thanks - TJ

Hi, yes, sometimes I watch the Engine Data display on my GLC250, generally its sits between mid 12V's, when the engine has stopped and accessories running on battery, and 14.2V - 14.4V, never higher though.

I don't know the significance of higher voltage, wonder if anyone else has observations?

Cheers