Trolling Motor Battery

[Goooh]

My battery is about 2 years old, I've just charged it when needed. The last trip I charged it and it was going out midway through my trip, I've usually gotten quite a few trips per charge.

Now I have it on my trickle charger and it drops 5% or more at least once a day, it's like the trickle charge is always kicking on.

Why is this battery bad already? It's an interstate marine battery, is this normal? Is it worth a crap? Should it be under warranty for its age?

This is my first boat that I got in 2011 brand new, not sure what's normal. Any help an advice for a replacement is appreciated.