The importance of an optimal method for electric power transmission is crucial for ROV operation. Meanwhile, only few studies have shown the effect of electrical power system from power supply to ROV.This paper proposes a design and implementation of electrical power system for ROV that developed by Tech_SAS team from Telkom University, Bandung, Indonesia. This work aims to obtain the optimal power system to supply ROV's electrical and electronic components. Tech_SAS ROV is developed to compete on 1st and 2nd ASEAN MATE Underwater Robotic Competition. The system has demonstrated that 48V electric voltage can be transmitted to ROV with negligible voltage drop when using 20 meter 12AWG cable. The voltage is converted to 12V using DC-DC converter in order to supply various ROV's electronic devices ROV safely and efficiently. Meanwhile, the microcontroller was used to as thrust control to manage current flow to DC motor. The system has been evaluated and demonstrates optimal results and provides a design consideration about ROV's power system especially on tether cable and power distribution scheme.

Disaster recovery from underwater earthquake, plane crashes into the sea, and monitoring underwater cables or piping for energy purpose are underwater missions for Remotely Operated Underwater Vehicle (ROV) in ASEAN MATE 2018 Competition. Two essentials factor to perform successfully in this ROV competition are design of an efficient communication protocol system and a low-cost communication hardware. In this research, an optimal communication system between RS-232 serial communication transmission and RS-485 serial communication transmission is developed to obtain the optimal solution. Both communication system is tested in Tech_SAS ROV-Telkom University Indonesia, a microcontroller underwater ROV based which used single microcontroller to control actuator, sensor and communication, and measured the Quality of Services (QoS) for end-to-end delay and packets loss. From the the experiment and evaluation for the two schemes, shows 12.57 ms end-to-end delay, 0% data packet error and $6 RS-485 communication system are the optimal solution for Tech_SAS ROV.