What size batteries should I purchase to operate a 24v, 65# thrust transom mount motor?

This transom mount motor is on a 16' pontoon boat, and is the primary source of propulsion. It's a Minn Kota, but I'm not sure of the year. I'm also thinking about using a solar panel for charging during the week, perhaps in conjunction with a marine charger while at dock.What size batteries should I purchase to operate a 24v, 65# thrust transom mount motor?
Minimum of two group 29's, wired in series.

d3100