Many choices for all of the above. For the TM, try to get the most thrust you can afford. 12 volts go up to 55 lbs thrust. Battery series go from 24, 27, 29, and 31. Keep in mind they get heavier as they go. Chargers need to be automatic, meaning that they quit charging when the charge is complete and go into maintenance mode where they just trickle charge as needed. On board chargers are nice and take care of all batteries at the same time by simply plugging them in. 2 batteries gets a 2 bank charger. Makes life simple. The car chargers only do one at a time and don't like wet conditions.