ESC REF
Electronic speed controller guide — BEC types, protocols and motor matching
BEC TYPES
LINEAR BEC
Built into most budget ESCs. Converts excess voltage to heat. Max ~1–2A output. Gets very hot under load. Adequate for 1–2 small servos. Avoid for multiple digital servos or >5A receiver loads.
SBEC (Switching BEC)
Switching regulator built into the ESC. 3–5A typical, higher efficiency. Runs cooler. Most mid-range ESCs include an SBEC. Check output voltage — some are fixed 5V, others are selectable (5V or 6V).
UBEC (Universal BEC)
Separate external switching BEC board. 5–10A+ output. Used when the ESC is opto-isolated or when servo count demands more current than an on-board BEC can supply. Wire directly to battery.
OPTO ESC (No BEC)
Optically isolated — no BEC output at all. Eliminates electrical noise between motor and receiver circuits. Required for large multi-motor setups with a dedicated UBEC. Common in FPV builds with separate 5V regulator.
ESC → FLIGHT CONTROLLER PROTOCOLS
| PROTOCOL | TYPE | REFRESH RATE | CALIBRATION | NOTES |
|---|---|---|---|---|
| PWM 50Hz | Analog | 50Hz | Required | Legacy. Throttle range must be calibrated. Shared with servo signal. |
| PWM 490Hz | Analog | 490Hz | Required | Faster analog. Still needs calibration. Common on brushed motor ESCs. |
| Oneshot125 | Analog | ~2kHz | Required | 125–250µs pulse width. Faster sync with FC loop. Still susceptible to noise. |
| Oneshot42 | Analog | ~4kHz | Required | 42–84µs pulses. Requires supported ESC firmware (BLHeli). |
| Multishot | Analog | ~32kHz | Required | 5–25µs. Fastest analog protocol. Rarely used — digital is preferred. |
| DSHOT150 | Digital | 3.75kHz | None | First digital DSHOT tier. No calibration. Error detection built in. |
| DSHOT300 | Digital | 7.5kHz | None | Standard recommended choice for most builds. Reliable and widely supported. |
| DSHOT600 | Digital | 15kHz | None | High performance. Use with 8kHz FC loop or higher. Requires good wiring. |
| DSHOT1200 | Digital | 30kHz | None | Experimental. Susceptible to noise. Not recommended for typical builds. |
| Bidir DSHOT | Digital | As above | None | Returns RPM telemetry to FC. Enables RPM filtering. Requires BLHeli_32 or AM32. |
Green rows = recommended. DSHOT300 is the best starting point for any new build. Use Bidirectional DSHOT if your ESC supports it — RPM filtering significantly reduces noise and improves tune quality.
ESC MATCHING CALCULATOR
CURRENT RATING GUIDE
Motor Max Current (A)
Number of Motors
ESC current rating should be 20–30% above motor peak. On 4-in-1 ESCs, the total rating is shared — check per-motor limits. Battery must be able to supply total system peak current continuously.
ESC SIZING GUIDE
| BUILD TYPE | MOTOR SIZE | ESC RATING | PROTOCOL |
|---|---|---|---|
| Tiny whoop / micro | 1104–1306 | 10–15A | DSHOT300 |
| 3" freestyle | 1306–1408 | 20–25A | DSHOT300 |
| 5" racing | 2204–2306 | 35–45A | DSHOT600 |
| 5" freestyle | 2207–2306 | 40–50A | DSHOT300/600 |
| 7" long range | 2506–2807 | 40–55A | DSHOT300 |
| RC car (1/10 brushless) | 3300–5000KV | 60–80A | PWM/Oneshot |
| RC car (1/8 brushless) | 1900–2200KV | 100–150A | PWM/Oneshot |
| Large multirotor (12"+) | 4214+ | 60–80A | DSHOT300 |