Need help! New to boating / fishing off a boat

Hi ladies and gentlemen. Just made an account and I'm looking for some information (new to boating so don't bash)
I'm looking at buying a sun dolphin sportsman (2 person). Anyone use one of these? And if so how are they? Also I'm looking into a trolling motor (Cloud Mountain 40LBS Thrust Electric) and 1 or maybe 2 Universal UB121000-45978 12v 100AH Deep Cycle AGM Battery. About how long should 1 battery last me let's say with 100% use? My main concern is what if my battery dies while I'm in the middle of the river and using paddles isn't an option? Is there a good portable charge (and by portable I mean no power from shore required) that will help make sure I can enjoy a full day of fishing? All I can find is jump starters or on board power bricks that need shore power to run.

---Information about locations where I fish on.
•It's the upper Ohio River in Pennsylvania and the mon river in Pennsylvania
•I very rarely fish on lakes
•if I'm not on a river I'm probably fishing on a creek inlet to the river (some can be deep with swift moving water at times)

Welcome to the forum.

So that it may get seen by more fisherman and therefore increase the chance of receiving some replies to your question you may want to re-post it in one of the fishing sections instead of here in the "Off Topic" section.