Tonka Boater
Well-Known Member
I'm on my 3rd year with my original batteries and I'm looking to switch to the Optima BlueTops. My boat will take a Group 27 or 31. I did some Googling and the specs look the same except for the dimensions. I can get the 27's for under $200 and I'm wondering if the only difference between 27 & 31 the physical dimensions?