Power: The power will come from batteries on land passing to the ROV via a tether. I am using two 12v motorcycle batteries in a series for 24v to the ROV. With 30m of 16g wire that will give me at least a full 12v with everything running. There is an app called ElectroDroid that helps you figure the volt drop depending on wire gauge, amps, etc. Very handy. I used a 24v to 12v converter to prevent overpowering. My camera is 5v so I also used a 12v to 6v converter for that. I used cat5 stranded wire for the relays and 16g speaker wire for the power. I wanted my tether to disconnect from the ROV so I used these connectors.