Hi while talking about radios, I have a 89 Alumacraft flat bottom jon-bass boat with 40 hp outboard motor, that has a front and rear deck, Under rear deck where a seat seat would be is two 12 volt batteries one for outboard motor the other for Trolling motor wired to a two phase charging system. I am wanting to add a third battery up front to driverside. Want to build a 4 to 5ft box and have battery in it in battery case for all electrical lights, fish finders, and stereo would this be ok to fix it like this?