Originally Posted by CatFan
As an engineer who has worked with batteries for many years, I can tell you you won't find anything in a reasonable size that will supply power in a boat as long as a plain old flooded cell Trojan SC225.
The reserve capacity (the only number that really matters in non-starting use) on the Optimas is way lower than typical deep-cycles, but they will tolerate abuse and still give longer service life. The biggest Optima deep-cycle has an RC of 155 minutes, while the SC225 has an RC of 225 minutes, which is almost 50% more than the Optima. A well maintained SC225 will continuously power a TM for 70 minutes longer than the Optima, and at the end of that time, the Trojan will just slow down, while the Optima will see a quick voltage drop that makes it unusable.
Walmart batteries are made by Johnson Controls, just like AC Delcos and Optimas. The Everstart MAXX has an RC of 205, and that's the only trolling battery I use. For the price, there is nothing close.