Until i get my 25hp outboard, I'm using a trolling motor. I think it's about a 30# thrust, 30" shaft. Boat is 14' V hull. I'm just wondering what size battery should give me a day's worth of fishing. I learned today that "duel" batteries are for starting engines and accessories, & also learned that "deep cycle" are used mostly for accessories such as trolling motors. But the price range is anywhere from $39.95 to $65.00 and beyond. How do i Know which will last the longest. I know conditions matter, but setting that aside - if we hooked two or three of them up to different size batteries and ran them till they stopped, is the biggest one going to last the longest? thanks
pastor lupe

Get one of the 730 amp deep cycles from Academy and that will work for what you need. I think they are $59 but they run them on sale about this time of year. I bought mine for $39 on sale.

I'm not great with electrical problems but having recently gone through what you are doing I will share some of what I have learned. If you look at the amp draw per hour for your trolling motor, should be in the book and maybe on the motor, and then divide that into the amp rating for the battery you will have an approximation of how long you can expect the battery to run the trolling motor. If that is your only means of power I would allow plenty to spare so you know you can get back to the dock. One other thing I learned was the heavier the battery the longer it will run. I bought a Trojan Deep Cycle from Gander Mountain, pricey at $129, that seems to run forever.

thanks that helps alot.
PL

So what happens if you buy a really expensive battery like that Trojan and lets say a Walmart deep cycle, and run them on a 24 Volt system. Will that matter at all?