Holybro Kotleta20

The Holybro Kotleta20 is an open-source ESC for the CAN bus, intended for PX4 and ArduPilot drones of the mid class. It drives one motor, weighs 8.8 g and runs the open firmware Sapog.

Instead of a current rating the manufacturer gives a continuous power of 500 W. Current follows from power only with the operating voltage: the higher the voltage, the smaller the current for the same power. For sizing one therefore works from the battery. Control is via CAN (DroneCAN), UART or RC-PWM; over CAN it also reports status values as telemetry to the flight controller. Sapog is open firmware whose source code can be inspected; that eases adaptation but needs a counterpart that understands DroneCAN.

Frame and law: CAN connection pays off with long leads and when speed, current and temperature are to be monitored. A mid-class multicopter falls, depending on take-off mass, into EU classes C1 to C3; Remote ID and operator registration concern the aircraft. On the bus every controller needs its own node identifier, and the line needs termination.

For selection it matters that the flight controller speaks DroneCAN and that the firmware versions fit together. At 8.8 g the board has little mass to absorb heat: at loads near 500 W it needs airflow. Wear shows at connectors and solder pads that crack under vibration; after a prop strike check the controller for traces of heat.