All answers are good and correct. Gel Cell or absorbed glass mat, or immobile electrolyte is good technology for use in enclosed environmental conditions. They do not vent hydrogen gas or spill acid, but are rather expensive and are difficult to find in amp hour rating sufficient for long trolling times. Most sporting good stores, academy, cabellos, etc should have sealed lead acid batteries, which should not spill. A good automatic charger , which reverts to trickle will save lots of battery money. Charge at 1/10 its amp hr. rating, ie, 80 amp hr. battery at 8 amps, then trickle at 1 amp.
Money spent on a good sealed lead acid may save 30-35 bucks if your wranglers/levis get eaten up by acid.(Or worse).
