Tech all you need to do is check the negative battery terminal for presence of a bms sensor this will verify if the vehicle runs normal smart charge or smart regenerative charging.
The up to 15.1v is for deep cycling only when the soc is lower than a predetermined level all this management of battery health is done between the bms and the bcm.
The bcm.tell the pcm how to drive the generator.
If the battery or generator control uniwithin the alternator are not oe I can see you having charging issues.
The bms reset is a manual reset and doesn't need ids , etis ids or fdrs to be utilized.
If I had more vehicle information id help gladly but without it we are repeating ourselves
Best of luck