FireDriver

I have 16' aluminum boat with a 50hp 2 stroke mercury and a 24v motorguide i3 trolling motor. I'd like to upgrade my trolling motor batteries to lithium as the lead acid just do not last very long. I generally use the trolling motor to steer and the main to push while trolling. I was looking at 2 12v 100aH batteries but didn't know if that would be overkill. Any info would be appreciated.