Power budget/usage

The Otter is battery powered, constraining the duration of missions it can perform. A power budget is given in the table below, showing the worst-case power usage for each component. The total capacity of the four batteries is 3660Wh, resulting in a worst-case duration of battery operation of 3660Wh/833.762W= 4.39h. As can be seen in the table, the motors dominate power consumption, and actuation should therefore be limited for long duration missions.

Description Hardware Voltage Current Watts
CPU RPI4 4GB + StratoPi CAN 12 1.4 16.8
GPS Hemisphere v104s 12 0.165 1.98
AirMax PoE injector + BulletAC IP67 24 0.3 7
4G router Teltonika RUT950 12 0.6 7
SignalLED Hella Marine NaviLED 360 12 0.08 0.96
Hydrophone Thelma TBR700RT 5 0.0044 0.022
Motors Full Torqeedo Ultralight 403 24-32 Varies 2×400
Total 833.762

Note that the power usage of the hydrophone is based on the TBR700 battery usage of 6 mA at 3.6 V, and the TBR700RT may use a some small amount more.