E220 coupe, 2014 (C207), 40K miles, under MB extended warranty. Battery reading was low (11.7V with engine off and down to 10.2V during engine start). MB put a new battery.
Now I noticed on driving, the voltage reading is always between 14.2-14.9V even if the car is driven for 1h with no AC/Heaters. This suggests the alternator is more or less working all the time when the engine is on. When the engine shuts down (for example start stop function is activated) the battery voltage reads 12.4-12.7V.
My understanding with smart alternator, they only work for a short period then stops when not needed (at least that was the case with the old battery which after 10-15 minutes driving the voltage is around 12.4-12.7 with no electric load on).
Could the dealership done any change in the alternator setting to make work more harder? Apart from poor fuel economy, is there any other risk of the alternator working all the time?
Thank you for your help.
A
Now I noticed on driving, the voltage reading is always between 14.2-14.9V even if the car is driven for 1h with no AC/Heaters. This suggests the alternator is more or less working all the time when the engine is on. When the engine shuts down (for example start stop function is activated) the battery voltage reads 12.4-12.7V.
My understanding with smart alternator, they only work for a short period then stops when not needed (at least that was the case with the old battery which after 10-15 minutes driving the voltage is around 12.4-12.7 with no electric load on).
Could the dealership done any change in the alternator setting to make work more harder? Apart from poor fuel economy, is there any other risk of the alternator working all the time?
Thank you for your help.
A