Red tops aren't a good choice for marine/storage use. Once they go dead or lost some charge...the damage is done. Any regular batt for the most part has a 3yr. In a boat better to run a marine/deep cell type for the average boat. I run a marine type in my 56 f100 as its not a daily driver.
Correct. FYI, Optima only makes two style of batteries. Deep cycle (light gray bottom) and starting (dark gray bottom). The top color has more to do with the type of terminal it has than anything else.
Red top = always starting
Blue top = Starting or deep cycle depending on bottom color
Yellow top = always deep cycle
Optimas are generally a group 34 which is close in size to a group 24 marine. They also do make group 27 and 31 which are less common.
Group 24 = 10" long
Group 27 = 12" long
Group 29/30 = 12.5/12.75" long
Group 31 = 13" long
The larger a battery the longer it lasts. The reason I suggest a group 31 is that it is a very common size, as it used in motor homes, heavy equipment, semi trucks, ect. Being common makes it a good bang for the buck, most good group 31s will last 3-7 years depending on use and maintenance. They normally cost between 85-150 depending on manufacturer/brand name and ratings.
