[Cheif 2]

You said the 12v lights run the battery down. Is that the case when you are plugged into shore power? Have you checked just the battery voltage when plugged in and after using the 12v lights for a considerable time? You need to do so after disconnecting the battery from the camper electrical system? You need to try to isolate the problem a little more before getting to the source of the problem. Let me know what you find.