There is a great article in the (Oct. issue) magazine, Bass and Walleye Boats, about the 3 different type batteries. Absorbed glass mat (AGM), gel and wet cell batteries. The one thing that made my mind up to get a gel is that you don't have to take care of them. Meaning, I sometimes don't get to fish but once a month. With a wet cell you need to keep a constant charge on it to get maximum life out of the battery. With the gel, you can leave it set and it won't hurt the battery at all. Just charge it and go. If you fish alot and are going to take care of your batteries then go with the wet cell. The one thing they said is with a gel battery you need a battery charger that was designed to include gel batteries or with a gel setting. You want a gel battery between 13.8 volts and 14.1 volts. If you go over 14.1 volts it can damage it. It's a great article I learned alot. I could try and fax it to you if you want. good luck.
because of the heat most batteries will last about 1 year. i have bought gel batteries glass matt ( optima) batteries. i have found that the everedy batteries at walmart are about the best deep cycle ones i have found. i get 2 to 3 years out of these. I used a gell for a starting battery and got 2 years put of it.
I replaced my wet cell trolling motor batteries with deep cycle marine gel type batteries I bought at Auto Zone. The jury is still out on them, but they are maintenance free. They are roughly about 30% lighter (about 10-12 lbs. lighter each), have about 20% more capacity each for their size then my wet cell batteries, plus they are 1-2 inches smaller in outside dimenions. It'great not having to add water to them. But the cost was about double for each battery versus the wet cell (around $160 vs. $80 each). I would want them to last twice as long for double this price. Time will tell if they are worth it to me. It's true about using the proper charging voltage. They are designed to be charge with less voltagle than a wet cell battery.