I have a 2001 Fleetwood Class A. I recently, within the past 2 months, put in new batteries for the engine and the coach. They all are now dead. I have been using AC so there has been no draw on them....
If you haven't had any trouble up till now, chances are the NEW batteries weren't fully charged when you installed them, or you have a bad connection made with the installation. If you get battery charger, get a good "Smart" charger.