My 2016 XTS has a battery voltage gauge, ( at least that's how it is labeled ). Lately I have noticed it is fluctuating any where from 12.2 v to 12.7 then an hour later 14.7v to as high as 15.2v.
I called the dealer service dept. he claims it is normal, that the alt. puts out what the battery needs. Never heard of such a thing.
Everything I have known, cars, motorcycles, boats 13.7 is the norm.
I think I have to bring it in to do***ent it.