We are building an observation class ROV operating at 100m depth in which we have used the Blue robotics T100 and T200 thrusters with basic ESCs. The battery will be off-board. So we have a 100m tether for power transmission. Since the current consumption is huge, the voltage drop across the tether will also be more. Thus we planned to supply 24V from the supply and use voltage regulator inside the hull, but the most of the regulators have strict current ratings of about 1A -4A, but one thruster itself draws upto 20A and we use 4 of those. Can anyone please help us in this problem? We need to regulate the input voltage we are giving to the ESC with higher current rating.
I assume you have determined what gauge wire you will be using and what the anticipated voltage drop will be at maximum anticipated current. What is the voltage value you desire to maintain at the ESC input? I don’t know of any small solid state voltage regulators that will handle your requirements, so the next question is why do you think you need a voltage regulator? Does you project require some form of automatic speed control to maintain constant thruster RPM? If that’s the case, use software with RPM feedback to maintain constant RPM as the voltage drops. A voltage regulator is not a good solution, and is impractical.
It will be very difficult to transmit much power through a 100m tether at 24V. Using a voltage drop calculator, you can see that the drop is pretty huge even for a low current (3A).
Most commercial mini ROVs use 200-400 volt power for transmission so that they can send a lot of power at low current and low voltage drop.