Power?!
The SpeedyBee F405 V4 55A Stack continues the legacy of accessible, feature-packed flight electronics for 5-inch freestyle and long-range quadcopters. Upgraded with an ICM-42688-P gyro fed by dedicated LDO power filtering, an aluminum heat sink on the 55A 4-in-1 ESC, onboard wireless Bluetooth tuning via the SpeedyBee App, and an integrated 4-level LED battery monitor directly on the FC, this stack brings high-tier convenience to a standard 30.5×30.5mm footprint.
Core Hardware Architecture
F405 V4 Flight Controller
Driven by an STM32F405 MCU with an ICM-42688-P IMU, the V4 FC features a built-in DPS310/BMP280 barometer, AT7456E analog OSD, 6 hardware UARTs, and 8 motor outputs for octocopter or X8 configurations. It includes a microSD Blackbox logging slot (supporting FAT16/32 up to 32GB) and integrated Bluetooth for full wireless Betaflight and INAV configuration.
BLS 55A 4-in-1 ESC Power Stage
Built on 3oz copper PCB tracks with an aluminum heatsink, the BLS 55A ESC supports 3S–6S LiPo input. Rated for 55A continuous (70A 10s burst) per channel, it runs BLHeli_S firmware (J-H-40) with support for DShot300/600 and includes a high-capacity onboard TVS protection diode to shield sensitive logic from voltage spikes.
Technical Specifications
Comprehensive technical specifications for the FC and ESC stack combination:
| Component / Parameter | Specification Detail |
|---|---|
| Main Processor (MCU) | STM32F405 (168MHz ARM Cortex-M4) |
| Gyroscope / IMU | ICM-42688-P (Dedicated LDO Power Supply) |
| Barometer | Integrated (DPS310 / BMP280) |
| Onboard OSD | AT7456E Analog OSD Chip |
| Wireless Connectivity | Onboard BLE Bluetooth (SpeedyBee App Configurator) |
| Blackbox Logging | MicroSD Card Slot (FAT16/FAT32 up to 32GB / 4GB log limit) |
| ESC Continuous / Burst Current | 55A Continuous per channel / 70A Peak Burst (10s) |
| Input Voltage Range | 3S – 6S LiPo (11.1V – 25.2V) |
| BEC Power Outputs | 5V @ 3A | 9V @ 3A | 4.5V @ 1A (USB Live) | 3.3V @ 500mA |
| Serial Ports / UARTs | 6x UARTs (UART4 dedicated to BLE, UART5 to ESC Telemetry) |
| Digital HD Air Unit Port | Direct 6-pin Plug-and-Play (DJI O3 / Walksnail / HDZero) |
| Mounting Pattern | 30.5 × 30.5 mm (M4 holes with silicone dampening grommets) |
| Dimensions & Weight | FC: 41.6×39.4×7.8mm (10.5g) | ESC: 45.6×44×8.0mm (23.5g) |
| Firmware Targets | Betaflight: SPEEDYBEEF405V4 | ESC: BLHeli_S (J-H-40) |
Integration & Build Considerations
Wireless Tuning & Bluetooth Calibration
The built-in Bluetooth module operates over UART4. By opening the SpeedyBee App on an iOS or Android device, full PID tuning, motor direction reversing, and CLI adjustments can be performed at the field without ever needing a USB cable or computer.
4.5V VBUS & TVS Spike Protection
The onboard 4.5V BEC powers receiver and GPS modules directly over USB connection, letting you acquire GPS satellite lock without powering up active VTX or heating ESCs. An integrated onboard TVS diode combined with the included 35V 1000µF Low-ESR capacitor protects sensitive ICM gyro logic against 6S back-EMF voltage spikes.