I have a 36v Ulterra with three 100ah lithiums on a 21.5 ft center console...BIG wire to the motor, probably a #6 as stated before...if motor speed is any more than 5 then I turn on the big motor because I can kill even those batteries in 2 hours at high draws. I only troll WITH or on an angle to the waves, not into them like the guys on the charter boats do.