BATTERY BOX replacement for the recessed battery box

Contacted Heartland about a replacement battery box for my '08 Sundance 5W. Measures approximately 9"Wx15"Lx10"high. With top and bottom vents. Its a two piece box with the top and bottom being the same and mounted asymmetrically. Here's the part number; 10710 @ $14.75 + shipping. I'm going to mount another battery on the left side of the front compartment where the current battery resides.

It will be good to have extra battery capacity, especially if you do any dry-camping. Are you going to vent additional box in the same manner as existing box?