Do try to verify the battery's condition. Roadtrek has had all kinds of missteps with the implementation of lithium batteries. The early years especially were very expensive for both owners and RT to correct or at least try to mitigate the problems.
Quite a bit of info in the class B forums. Not sure if a direct link is allowed to another forum. Google or Duck Duck Go are your friends.
1998 Safari Trek 2480, 7.4 Vortec
'15 Kawasaki Versys650LT, well farkled