I have a Perko switch, and just trying to make sure I'm understanding the instructions right, because they aren't very specific. My plan is to run all the electronics except the Trolling motor and the main motor on one battery. One battery for the trolling motor, and one just for starting the main engine and to run an inverter off of. I have this perko switch that I wanted to use to allow me to use both batteries for the trolling motor if I found the need. The way I understand it now, one battery hooks up the the No1 on the perko switch, the main battery you want to use, and the other battery hooks up to the No2 on the perko, both from the positive terminals. The part I'm confused about is it then says to hook up the starter switch of the motor to the common terminal on the perko switch. So what then do I do with the negative side of the wires from the trolling motor? Hook it up to one of the negative terminals on the battery?