From the picture you can see what has happened. The battery box filled with water and then froze. I know there are two vents on the cover and this appear as the only place the water could have entered. There are no exit holes. Once I extracted the battery and repaired/replaced the fuse wire I decided to drill two 1/2" holes in the battery box bottom. Has anyone else experienced this or see a way to prevent it other than drilling the holes?