Topside and subsea power unit

Have any of you tried to make your own topside power supply unit?
In that case, can you recommend what type of topside transformer 240VAC to 400VDC and the subsea DC-DC step down converter (400VDC to 15VDC) you went for?
I’m thinking about building my own setup on this, since it’s quite expensive to buy the whole setup from a supplier.

Everyone on here will discourage you from trying to do this due to safety concerns.

If you want to try anyway, I’d suggest you take the approach used by Deep Trekker to extend the bottom time of their ROVs.

Deep Trekker powers the ROV from an internal battery as usual, but they send a constant DC current down the tether to charge the battery during dives.

The charging current isn’t enough to completely power the ROV, but it can extend your bottom time dramatically depending on how hard you’re running the ROV. Since the current requirements are less extreme, you can use a much lower DC voltage in the cable and still see an acceptable rate of charge.

If you’re operating from a boat, you could possibly use the boat’s 12V battery as a power source, step it up, send it down the tether, then step it down at the ROV.

I’m a big fan of Vicor DC-DC converters for this sort of thing.


I made a power unit using 3 power supplies.

  1. 220VAC to 12VDC , 30A
  2. 220VAC to 12VDC , 30A
  3. 220VAC to 5VDC , 10A

First and second power supplies are for motors. I have 6 motors that have 12VDC , 8A. First power supply feeds 3 motors and the other one feeds the other 3 motors.
I didnt want to connect 2 P.S. together because they can become unstable and cause safety problems.
Third power supply is for raspberry pi, servo motor, and 2 lights.
I put them into a box for look more tidy.