Today was the final test in the tank. Everything is operational with a tremendous power with the motor running on 24volts. Since the ROV has a mass of 35kg it is smooth to operate. Next dive will be the real deal in the sea.
Oystein do you sell your VDC power supply solution for testing?
If you go down the route with topside power you need to change your tether as well pr the voltage drop will prevent you from the benefit from topside power.
If you go for 14 AWG conductors in the tether you can use 400volt DC DC converters fitting inside a 3" enclosure. The converters I am using is 600/24vdc. And need a 8" enclosure, which again must be oil compensated for depths greater than recommended by BR. Check out Vicor DC DC converters or Absopulse. Topside I use a Lamda AC / DC power supply.
Remember: Now we are also looking at danger of electrocution !!!