Advanced Power Drives (APD) 120F3[X] v2

The APD 120F3[X] v2 from Advanced Power Drives (Australia) is a single-motor ESC for mid-size multicopters and heavy FPV builds. It drives one motor, weighs 20 g and fits a high-current stage into a small housing.

The 120 A continuous rating is the current the controller delivers on a sustained basis; the motor should stay clearly below it so that heat and a warm environment have headroom. The 200 A peak is allowed only briefly, the manufacturer states the duration, and it does not count for sizing. The product page gives 12S as the upper limit, i.e. 50.4 V fully charged; the documentation mentions up to 14S, so the manufacturer's release should be in hand before running above 12S. The signal paths listed are PWM, DShot150 to DShot600, ProShot1000 and Bidirectional DShot. The number after DShot is the bit rate in kbit/s; Bidirectional DShot reports motor speed back to the flight controller, which feeds RPM filters with it. Telemetry is on board. The firmware comes from APD itself, even though some retailer pages name BLHeli_32.

Frame and law: the aircraft counts, not the ESC. Take-off mass and type of operation decide; series-built aircraft carry an EU class, for example C1 under 900 g, C2 under 4 kg or C3 under 25 kg, and Remote ID is mandatory for C1 to C3. On 12S each ampere-hour of battery is about 44.4 Wh; from roughly 2.3 Ah a pack passes the IATA 100 Wh line, from roughly 3.6 Ah the 160 Wh line.

When choosing, the motor decides: its continuous current plus reserve must stay below 120 A. Wear shows first as heat: a discoloured board or a burnt smell. At 120 A the capacitors at the battery input and the solder joints of the power leads age through vibration and thermal cycling. After a crash or a prop strike, check the leads and the housing.