Big Matt 03 E55

I am getting a battery fault every morning it is below 40 degrees F. All summer/spring car is fine. Past two years with all new batteries, two new alternators and voltage regulators the problem still persists. on start up volatge display on cluster shows 12.3-12.9 and goes up to 14.1 once engine starts. After a minute or so the alternator quits and goes to battery power and the red fault message displays along with the convenience functions message. odd thing is if i shut off the engine and start it again its fine. sometimes twice but it always fixes it self. Throughout the day no more issues. If anyone has had or seen this issue please help me out cause i can not afford to keep this up with maybe its this or that. Only does it below 40 and only first or second start up. Both batteries take and hold charge, new alternator and voltage reg. Thanks