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.