Ok, so I don't really know anything about electrical stuff, or whatever. I have a little box called a Kill-A-Watt to see the power draw for 120V A/C appliances. I recently got a trolling motor for my paddleboat however (yes I'm lazy) and have been using my 16ah sealed battery with it. What's the best way to know how much power you're drawing at any given time? There's gotta be some simple device that does it, or a way to measure it.