12v battery, deep cycle marine. I think battery boxes are pretty standard, but I'm not sure....

You might consider the Endura Max series. Cost slightly more but have a battery tester and a feature that is advertised to prolong battery life up to 5x as long. Of course, you and I both know 5x is a gross exaggeration, but mine does seem to be better at preserving the battery life than my previous motor, so I think it's at least sort of legit.