Deep Cycle Battery Trouble

My deep cycle batter is a 2007. When I charge it with the 6 amp onboard charger acid forms on the top of the battery by the covers. It doesn’t seem to hold a charge like it used to. Yesterday on was on lake Pepin and the battery gauge on my trolling motor showed it needed to be recharged and the trolling motor was basically dead. After not using for about a half hour the battery gauge showed it being good again. Is this normal? Is the battery bad? Is my charger bad? It was pretty rough out there yesterday and I did run the trolling motor pretty hard but I just thought it was weird that acid comes up when I charge it and that it after sitting it shows it is good again.

Any advice or input is appreciated.

Thanks
Mike

Sounds like a classic weak battery, charges full, but doesn’t give the amps like it used to. You could have it tested Batteries plus test them for free, I suspect lot of places can test it too. All that being said I’ve had batteries that tested OK, but were not to their full potential.

Sounds like you’re due for a new battery to me.