Trolling Motor Battery Run down

Optimas, because of their spiral construction, have about 1/4 less reserve capacity than other batteries of the same group size. The Optima Blue and Yellow Top 31 series both have a RC of only 155 minutes.  Other 31 series deep cycle batteries have RC’s of around 200 minutes.  For example, wet JCI/Interstate 31’s have 210 RC, wet Deka 31’s have 185 RC. If you want to stick with AGM (which aren’t really necessary for the troller), then the Sam’s Duracell/Deka 31’s have an RC of 210.  Best to replace the Optimas with other heavier group 31 batteries with higher RC.