Now a days the digital maximizer option on the Minnkotas is a must,big difference in battery life.So the Minnkota Traxxis is the one and the smallest is 45lb thrust.
I have an older Endura 30lb ,it moved my toon around no problem it also moved a 1448 jon if it wasn't windy and if i just kept it on low and used it sparingly i could get a couple of days out of a group 27 battery.
So if your only a day tripper and you only go short distances the Endura will do.If you like to go for multiple days on one battery and like to troll then the Traxxis is the one.