I got my trolling motor in the mail today. Opened it up and went to test it out.. the battery terminal rings don't fit any of the posts on any of my four deep cycle batteries.  Is this normal? What's the deal? Why wouldn't they make the connectors the same size the battery posts are. 

Because there are different size battery post. It is not a standard on all of them, had to switch them when the new batteries were out in my boat.

Do you know what size the larger battery posts are? I'll have to replace my smaller ones with the larger ones.