Lithium (LiFePo4) batteries are perfect for trolling motors because they offer high capacity storage per pound (nearly 4x), consistently high power at same voltage (means higher operating efficiency), much longer lifespan (up to 10x and more), less weight (half), longer shelf life and rapid efficient charging (20% more efficient), availability of 95% of rated battery amperage instead of 50-60% available in lead acid. Some even offer a bluetooth app to your phone so you can see exactly how much power you have left at any time.