Battery Box planning wisdom needed (kinda long)

I installed a second battery in our Alumiscape Fifth wheel. Factory sent the second box, like some Boat boxes with a cover and vent tube and tie down. Both were vented to outside with clear tubing and a hole in the bottom of fifth wheel. It was sealed around the edges. Just had to be sure that no pressure was generated into the tube. I was somewhat concerned about acid vapors damaging some surface and then the underlying material under it. Never had a problem that I remember.