GEPRC O4 Series Step-Down BEC is a miniature voltage converter suitable for powering DJI O4 Air Unit and O4 Air Unit Pro digital video transmitters. It converts a 3-6S (10.5-25.2V) input into regulated 9V or 5V output voltage.
The BEC is installed between the flight controller and video transmitter using 6-pin connectors with clearly marked input (IN) and output (OUT), preventing incorrect connection. UART (TX/RX) and SBUS signals pass through the board unchanged. The default output is 9V; bridging the 5V pad on the underside switches the output to 5V. The G and 5V pads can also be used to power LED strips.
The board features an EN pad for electronic output switching. Connect it to a free flight controller pad, assign the PINIO function in Betaflight, and control video transmitter power with a switch on the radio transmitter. The board measures 17x8.3mm and weighs 1g, making it suitable even for small builds.
Important warning: Input voltage must not exceed 25.2V, otherwise the module will be damaged. The BEC can only step down voltage, not increase it.