1. Most 16- to 18foot boats require 70 to 80 pounds of thrust. That’s a 24-volt motor requiring two batteries.
2. Larger boats call for 105 to 112 pounds of thrust. That’s a 36-volt motor requiring three batteries.
3. Two or three additional batteries take up considerable space. Make sure your boat has enough storage.
4. You need deep-cycle batteries for a trolling motor. Each adds 35 to 45 pounds of weight to your boat and could increase its draft. Consider if you need a 36-volt motor or can get by with a 24-volt.
5. The extra weight could also affect the boat’s performance, especially if the batteries are mounted far aft or forward of the beam, so carefully select the best mounting location.