Hi guys I am going to add a second battery to my 27 Fountain.
I am going to add another battery box on the other side of the engine, wire the ground to the grounding block, put in a 2 battery switch and wire the positive to the other battery switch. Anything I am missing? I decided not to trade up to a 29, I am adding a BB blades prop which will get a lot of the speed and not go thru the PITA of buying a new boat. Mine is nearly perfect.

I would also like so info on adding another battery. I do have a perko already setup for 2 batteries.

Nope, straight forward for the most part. Battery 1 to post 1...Battery 2 to post 2 and starter to the common post.
Not sure what the ground block is on a fountain....i would run the grounds straight to the engine block as ground to get best current supply from the batts when starting.

the grounds and bonding point is on the transom