Quote Originally Posted by ryanmitchell View Post
Gents. Only had our boat for a year, we use it a lot. Charge it up and burn it down pretty quickly as we stay out all day dmost outings. The battery seems to die down rather quickly. We have one battery up front and one in the back. We have an on board charger that we just plug in which is nice. We are going on a 4 day trip, and want to either replace it or have a spare.

Any recommended brands of batteries?
If your using lead acid batteries they should be charged immediately after even a partial discharge or the batteries will start to sulfate which greatly reduces battery capacity. Even a new battery that has been left discharged for several days or weeks will never be able to be recharged back to its full capacity or may not take a charge at all.
I have a 24 volt system with optima batteries (previously used common lead acid) going on three years with never a problem. First thing I do when parking the boat is to plug in the battery charger.

I could go on & on & on about batteries but the main point is proper charging.

Steve