by noseoil » Tue May 10, 2016 7:35 am
12 x 20 x 12 is fine for a single battery, what Lauren said. No reason it won't work, but as KC said, you could always relocate the jack & have a bigger box.
What's the biggest thing you need in the tongue box & what else goes inside? If there isn't enough room for your plans, move it forward to open up more room, if not, just use what you have. A group 31 battery is about 7" X 9 1/2" X 13" so the box would fit a bigger battery, but not a lot of everything else.