Which ever size you like $$$, I can't tell you what you need. I use my batteries just for lights and nothing else. I think they are the cheapest Wal-Mart sells, about $90 in the marine battery. Yes, you can cut the plug off and use alligator clips. Lot of trial and error over the years to get what I like now and it could change at anytime. Led lights are getting better and better. I've had lanterns, flounder lights, clamp on, submersible and now curly bulbs and submersible lights. Who knows when I'll settle down.