Discovered something on my 2006 Chalet Alpine. The battery box has a couple of little raised squares on the top of the box. Their purpose is to vent the box in case of any kind of gas build up. The problem is that any water sitting on top of the box will drain into the box through these vents. At the time I kept my trailer covered but not the tongue. Living here in the PNW it rains all winter. In the spring I went to change the porch light bulb to LED and it wouldn't come on. Traced back through the electrical system until I got to the battery. Opened the battery box and discovered it was completely full of water - covering both terminals of the battery. Disconnected the battery and pulled it out. There wasn't a single drain hole in the box! By golly there is now though ...several to be exact. Fortunately, the battery survived.