Power & BEC

How to feed the receiver, the MPU6050 and the wing servos from a single battery — BEC selection and wiring.

Servo power budget

A single wing servo can pull 1–2 A transiently at reversal; three servos plus the receiver and gyro demand a rail that never sags. Size the BEC for the stall current of all three servos summed, not their idle current. A 5 V / 3 A switching BEC is a safe baseline for most 2–4 g micro servos; larger wings need 5 A or more.

Choosing a BEC

Prefer a switching (buck) BEC over a linear one: linears burn the voltage drop as heat and collapse under burst load. Match the BEC voltage to the servo rating (5 V for most micro servos, up to 9 V for HV servos) — but keep the receiver on its own 5 V feed if it lacks a wide-input regulator.

Receiver rail

Most ELRS receivers take 4.5–8.4 V (1S–2S) directly and regulate internally. Feed them the raw battery when possible; only step down for the servos. The MPU6050 breakout (GY-521) accepts 5 V and makes its own 3.3 V.

Wiring diagram

Battery ──┬── BEC (5V) ──┬── wing L servo (5V)
          │              ├── wing R servo (5V)
          │              └── rudder servo (5V)
          │
          ├── RX (4.5–8.4V rail)
          └── GY-521 (5V, onboard 3.3V reg)

Tie every ground to a single star point. A floating ground between the RX and the servos is the classic cause of jitter and brown-outs — one shared GND is non-negotiable.