Most trolling motor shopping starts backwards — people pick a thrust number because it's what their buddy runs, then find out on the water it's either underpowered in wind or way more battery than they need. The math below starts from your boat's actual loaded weight (boat, motor, full fuel, gear, and people) and conditions, then sizes the system around that.
Trolling Motor Power
Size your thrust to your actual loaded weight, then check how long your battery bank holds up at the speed you'll really run.
12V · 24V · 36V
Thrust Sizing
Rule of thumb: 2 lb of thrust per 100 lb of fully loaded boat weight, scaled up for wind/current.
Recommended Setup
96
lb thrust recommended
Suggested system24V
80–112 lb class motors typically run 24V.
Battery Runtime
Estimate run time at a given speed setting. Power draw is modeled off real trolling-motor spec sheets — actual draw varies by motor and prop.
Estimated Runtime
3.4
hours at this speed
Draw at this speed38.5 A
Usable energy2160 Wh
Model: ~12 W of input per lb of thrust at full throttle, scaled down through the speed range (current draw falls off faster than speed — most motors only pull 25–35% of max amps at the 70% speed click). Cold water, weed load, and prop fouling all shorten real runtime.