Kevin,

I’m in the midst of building a small submersible ROV with a 200 ft tether, so I can see what’s under the waves as well as above.

I’m considering three power solutions for the ROV, on-board batteries (last resort), power in tether at 48 volt DC, or power in tether at 110 volt AC. It’s about the last two options that I have some boat wiring questions.

My idea with 110 volt AC is to get a 400-500 watt inverter, plug it into the DC port in my cockpit, and use an AC-DC converter in the ROV to get 12 volt power, hopefully about 10 amps. I want to run two-wire conductor between the inverter and the ROV because it weighs one third less than three-wire and I want to minimize the weight bulkiness of the tether the ROV will be towing around.

Alternatively, I could get a step-up converter to go from the cockpit’s 12 volt to 48 volt, then step-down from 48 volt to 12 volt on the ROV. A 200 foot 12 volt tether would be way too bulky.

I’m concerned about several things.

1. Are there any glaring safety issues with these during normal operations?
2.  Assuming I am going to eventually get a short, what are the risks I could face and what precautions should I take in anticipation?
3. Am I opening myself up to some kind of galvanic action disaster?

Thank you,

Orrin

Hi Orrin,

I would set up your boat wiring with the 110 volt version.

Run the ROV through a GFCI. If your two conductor wire has a shield, connect it to the case ground on the ROV and to your AC ground. Any AC fault will trip the GFCI long before the risk of an AC shock.

Please send pictures when you project is complete,

Kevin