Where to locate second battery?

[lymanguy]

I have a 2013 livinlite 10' truck camper, and would like to add an additional battery. Does someone familiar with the battery location on the back right of the camper know if there is enuf room for a larger battery box in that area, or do I need to add one inside the camper. I might have space above the gas bottles, but don't want the battery up so high.