The best answer, as it would confirm not just how the RV was supposed to be wired, but also how it is now functioning is to use a VOLTMETER. Easy for us to walk someone through this.
That, along with exactly what converter or charger he has would lead to a much better understanding of the charging function.
Totally agree we/the Forum are here to help. But, one of the "got-ya's" on any forum is without specific information many, many posts, even by very knowledgeable people are less than accurate for that specific RV.