Agree with Skiff89jr.

They have a 12 volt series that will accomodate.......but would look at size of your
boat and what you plan on doing with it................Variable speed means you can
control speed from barely moving to haulin bottom.

Trolling for 6 - 8 hrs a day - the 24 volt is best way to go...............
Unless running an alum boat 16 ft or less - 12 might work ok............