Hey guys I just ordered my 2017 XP4 Turbo. I am planning on doing a dual battery kit. What I need to know is what is the largest size battery I can add (dimensions) while retaining the stock battery. I have searched endlessly and no one has posted the dimensions of the empty space for the 2nd battery. I have only found battery suggestions, which is great but do I have room for an even larger battery? I really need this so I can purchase the biggest deep cycle battery possible in advanced. Please advise.