Troll motor battery suggestion.

[keithdog]

I have a Motor Guide 55# thrust troll motor on the back of my 12 foot Jon Boat. A couple years ago I replaced my leaking battery with a new Cabelas AGM class 24 deep cycle/starting battery. I thought this battery would take care of getting me around for a good days fishing. I thought wrong. After 5 hours of use, I have to start rowing in order to have enough juice in the motor to get the boat back on the trailor. My back does not like that one bit! So now I'm having to get another battery, I just don't know what I should get. Will a dedicated deep cycle battery last longer than a combination deep cycle/starter battery? I don't want to spend $300.00 on a new battery, especially since this AGM battery is fairly new. I'm going back and forth on buying say a class 27 battery and using that as my main battery and having the currant battery on board as a back up, or getting a large deep cycle battery which should last me through out the day. And should I get a dedicated deep cycle battery or would a combination deep cycle/starter battery sufice? I was at a battery store in town here and they have a large Deca deep cycle that the salesman says will run me all day long, but it's $329.00! OUCH!!! My old WalMart battery started leaking into my boat after having it for 3 years and so I'm shy of buying another one of those. A maintenece free battery would be great if I could get a good deal on one. Any suggestions? By the way, my boat does not have an outboard so the trolling motor is my main mode of transport.