I have a Motorguide 50lb'er on the back of my 14' Northwood. Great little motor. I have used it in the salt and on lakes. It always got me there and back.
As far as batteries go, get 'em at Costco. They are half the price of normal places.
I have a 750 CCA (big) Deep Cycle and run lights(when necessary), live well, fish finder, and motor for eight hours smile .
_________________________
Carl C.