Batteries
 

Bought a boat over the winter from out of state and I brought it back to be reviewed by the shop I use here. They indicated to me that
"Boat has (2) 27 Series Deep Cycle Batteries Only- Should Have 27 Cranking Batteries for Different Charging Rate"

A friend got me a deal on some batteries that have 675 CCA and 875 MCA (Ameritron 8-27MBP - Batteries are offbrand from Interstate). I am not sure of the spec info on the ones that are currently installed in the boat. My question is would I install the (2) batteries that I just procured or should I only be replacing one?

Thanks

Generally you want a dedicated starting battery for the engine, and a deep cycle for the accessories like stereo, fridge, etc. There are some deep cycles that suppose to be dual purpose, but it’s best to run a single purpose battery for the type of job it’s doing. I am on the beginning of my 9th boating season with my (2) group 24 1000mca vita-plate marine starting batteries. This year I had to replace my Deka Marine group 27 deep cycle battery after 8 full boating seasons.

I run 2 blue top optima deep cycle on mine... No issues in 3 seasons. But mine stays plugged into power when not in use.