In both cases - Cathy's 2015 and Paul's 2014 - all of the wiring is run through a single hole in the box (sealed around the cables with putty). Cathy's long and narrow box has two extra holes, which are filled with putty. Neither of them has a vent hose attached anywhere around the sides, at not visible at the top of the box.
The idea of a sealed box is to separate the batteries from the trailer interior, but it also needs to be vented to outside to be effective - otherwise the gases would endlessly build up, and they can't do that. Is there a vent hose mounted lower (out of sight), or in the lid?