Arcing Near Battery

[anyheading]

Last week while cleaning the trailer after a trip I saw an obvious arcing had occurred on the frame and door near the battery in the forward storage locker (see photos). I had stored a portable satellite antenna and its stand in the locker and assume it was somehow responsible for the arcing, although I saw no damage on any of the antenna parts. Has anyone else experienced this? Aside from not storing the antenna there, are there any other precautions I should take to avoid future problems.