Designed and manufactured by our friends at Outland Technology, the Outland Technology Power Supply (OTPS) allows the BlueROV2 to be powered through the tether so that you can run indefinitely and without any batteries! It has a safety-focused design that is simple to install, easy to use, and built with the rugged reliability that Outland Technology is known for.
How It Works
The challenge with powering any ROV from the surface is the electrical power loss through the tether. A long tether with small wires, like that used on most ROVs, has an electrical resistance that causes a voltage drop proportional to the amount of electrical current passing through the wires. The best way to overcome this challenge is to transfer the power at a high voltage and low current, minimizing power losses. The Outland Technology Power Supply does exactly this by converting normal household power (100-240 VAC) to 400 volts DC to transfer through the tether. Once it reaches the ROV, the 400 volt power is converted down to the 15 volts needed to power the ROV.
The OTPS system can provide a continuous 1,000 Watts (66.8 A at 15 V) of power to the ROV so that you can operate indefinitely even in currents and harsh conditions. As the power draw approaches the 1,000 Watt limit, the output voltage will automatically drop to limit the power drawn by the ROV.
The system is comprised of the Topside Power Supply Unit, the ROV Power Supply Enclosure, and the High-Power Tether Cable with Connectors.
The Topside Power Supply Unit
The Topside Power Supply Unit is built into a compact and easily transported hardshell case. Inside it has a high-voltage power supply, a built-in Fathom-X Tether Interface board, and a ground fault interrupter (GFI) for safety. It’s meant to be operated with the lid open for cooling and has a built-in laptop shelf that minimizes the table space needed to operate the ROV. While most of the internals are off-limits to the user, a special user-accessible section gives access to the Fathom-X board, 12 V power, and the auxiliary tether wires.
Since it includes a Fathom-X communication board, the topside unit connects directly to the laptop via a USB cable and there is no need to use the FXTI box.
The ROV Power Supply Enclosure
On the ROV, the battery enclosure is replaced with the ROV Power Supply Enclosure, which contains a power supply that converts the 400 volt power down to the 15 volts needed by the ROV. It comes with a pre-installed power cable and a tether signal cable with penetrators, making it a drop-in replacement for the original battery tube. The enclosure is equipped with two wet-mateable electrical connectors that allow the ROV to be connected and disconnected from the tether cable.
The High-Power Tether Cable with Connectors
The High-Power Tether Cable is specially designed for this application and has five twisted pairs of varying sizes for each function. Two 23 AWG pairs are used for the primary isolated power transmission while a 24 AWG pair is used for a solid connection to the earth ground to help detect any safety faults. One 26 AWG pair is used for the primary Fathom-X communication and another is available for auxiliary devices.
The tether is available in 125m and 250m lengths. It is not compatible with the Fathom Spool at this time.
The Outland Technology Power Supply is designed with user safety as the absolute priority! Outland Technology has been designing high voltage power systems for 35 years and knows their stuff when it comes to safety! That experience is built into each of these power supply units.
The primary safety device is a line insulation monitor (LIM), referred to throughout the system and manuals as a ground fault interruptor (GFI), that is built into the Topside Power Supply Unit. The GFI watches for any current leakage in the system and automatically shuts off the power if it detects any unsafe events. It’s designed to comply with the guidelines of the IMCA Code of Practice for the Safe Use of Electricity Under Water. The Topside Power Supply Unit has a test switch so that the GFI’s functionality can be verified before each dive.
The power supplies in the Topside Power Supply Unit and the ROV Power Supply Enclosure are isolated power supplies, meaning that there is no direct electrical connection between the 100-240 volt input power and the 400 volt tether power. Similarly, there is no direct electrical connection between the 400 volt power and the 15 volt power on the ROV. This further prevents any faults or safety issues and also prevents low-voltage current leakage from the thrusters or other ROV components from triggering the safety shutoff.
The entire OTPS system is built with detailed attention to safety. That includes the use of tamper-resistant fasteners, appropriately rated electrical connectors, and clear safety markings. Regardless, it’s still a high-voltage device and every caution should be taken by the user to use it safely. Check out the official user manual for more information and warnings.