Chip prices have gone up significantly in the past couple of years, making FPV electronics more expensive than ever. The Speedybee F405 V3 FC and 50A BLHeli_S 4in1 ESC might be the best value stack you can get right now. It offers most if not all the modern features one would want in a standard FPV drone, and it’s also suitable in a huge range of different builds and styles.
New to FPV? Check out my flight controller buyer’s guide.
Table of Contents
Where to Buy?
Stack: Speedybee F405 V3 FC + 50A BLHeli_S 4in1 ESC
- GetFPV: https://oscarliang.com/product-szri
- AliExpress: https://s.click.aliexpress.com/e/_DDolH5v
- RDQ: https://oscarliang.com/product-oibq
- Amazon: https://amzn.to/3FdpdlQ
- Speedybee: https://oscarliang.com/product-z1sb
Just the FC: Speedybee F405 V3 FC
- GetFPV: https://oscarliang.com/product-hbaf
- RDQ: https://oscarliang.com/product-vrin
- NBD: https://oscarliang.com/product-3dpx
For the FC:
- 5x M3 30mm steel hex screws
- 1x SH 1.0mm 30mm-length 8pin cable (for FC-ESC connection)
- 5x M3x8mm Silicone Grommets
- 1x 6pin cable(80mm) for DJI Air Unit / Vista
For the ESC:
- 5x M3x8mm Silicone Grommets
- 1x 35V 1500uF Low ESR Capacitor
- 1x XT60 Power Cable(70mm)
- 5x M3 Silicone O Ring
The Best Value Stack?
At US$69.99 for the whole stack, or US$40.99 for just the FC, I believe this is currently one of the best value stack/flight controllers on the market. It’s truly amazing how they managed to pull it off with this low price.
Maybe cheap, but it has all the features one would need in an FPV drone, and fits in almost any build you can think of: 4S/6S, quadcopter/hexacopter/octocopter, analog/digital, freestyle/racing/long range, Betaflight/iNav…
Specification
F405 V3 FC
- Betaflight Firmware Target: SPEEDYBEEF405V3
- MCU: STM32F405
- IMU(Gyro): BMI270
- USB Port: Type-C
- Supports 3S – 6S Input
- OSD Chip: AT7456E (Supports Analog)
- Built-in Barometer
- BEC: 9V 2A + 5V 2A + 3.3V 500mA
- Micro SD Card Slot for Blackbox
- Onboard LED battery indicator
- 8 Motor outputs (ESC signals)
- 4 x full UARTs + 1 x half UART (RX4)
- Dedicated DJI Air Unit JST connector (solder pads are also broken out)
- Built-in Bluetooth for wireless configuration via Speedybee App
- I2C: Supported. SDA & SCL pads on the front side. Used for magnetometer, sonar, etc.
- Supported Firmware: BetaFlight, EMUFlight, INAV
- Mounting holes: 30.5 x 30.5mm (4mm hole diameter)
- Dimension: 41.6(L) x 39.4(W) x 7.8(H)mm
- Weight: 9.6g
50A 3-6s BLHeli_S 4-in-1 ESC
- BB21 MCU
- Firmware target name: JH-50
- Power Input: 3-6S LiPo
- Current Rating: 50A x 4 (continuous), 55A (burst 5 seconds)
- Onboard Current Sensor: Scale=386 Offset=0
- Supports DSHOT300/600
- TVS diode
- Mounting holes: 30.5 x 30.5mm( 4mm hole diameter)
- Dimension: 45.6(L) * 44(W) * 6.1mm(H)
- Weight: 13.8g
Closer Look at the Speedybee F405 V3 Stack
F405 is slower than F7 in terms of clock speed, but it does not matter so much for the current version of Betaflight since 4K PID loop frequency can perform arguably just as well as 8K. But if you insist on running 8K looptime you may consider a F7 FC instead. It uses the BMI270 gyro, which means you will be running 3.2KHz PID looptime at most. In fact the F405 has more memory than the F722 which is used in the F7 V3 stack, so in a way the cheaper F405 is better when it comes to longevity.
The F405 V3 FC has a great layout, the solder pads are large and easy to solder, and they are well labelled without the need to look it up in the manual.
There is a 22mm wide cutout in the front of the FC, which is to leave room for the FPV camera in certain tight frames which is thoughtful.
There are 8 motor outputs (M1-M8), allow you to use this FC on an hexacopter or octocopter.
Unfortunately there’s no flash memory for Blackbox which is a shame, but there’s an SD card slot for that instead. Personally I prefer flash memory as you can just plug in the USB cable and download the logs, but I guess the SD card slot might have helped to keep the cost down. Looking at the bright side, you can have up to 4GB of storage when using an SD card so you will almost never run out of storage.
There are 5V and 9V BEC (both are rated for 2A), you can power your VTX off the 9V to reduce the chance of voltage spikes damaging the VTX. There is a JST connector on the FC, makes it plug and play with DJI Vista/Air Unit, Walksnail Avatar, and HDZero VTX.
There’s an OSD chip onboard, so it also supports analog FPV system.
Something I have not seen before on an FC is the battery indicator (4 LED’s), which shows the voltage level of the LiPo plugged in.
It has Bluetooth built-in, which allows you to configure Betaflight from your phone wirelessly (using the Speedybee App that you can download from the App Store)! Unlike the F7 V3 version, the F405 V3 doesn’t have WiFi, so you cannot flash firmware from the app, to do this you have to use the USB cable or Speedybee Adapter.
There are 5V, GND and LED_Strip solder pads at each corner (D1-D4), making LED wiring easy and clean. Note that all LED pads are connected in parallel, they will just mirror each other, so you cannot have different LED config for each corner. Actually the F405 V3 has a built-in LED system, to let Betaflight control the LEDs, you need to long press the boot button when the quad is powered on. However, the FC doesn’t seem to remember the setting and you have to press the button every time to switch to Betaflight’s LED system, which is slightly annoying.
There are 4 full UART available (plus a half UART – RX4 dedicated for ESC telemetry), these UART can be used for connecting your receiver, VTX (smartaudio), camera (UART control), GPS etc.
There is a barometer onboard, not really useful for Betaflight but need it or not, it’s good that it’s there.
And it uses USB-C connector which is more robust and easier to plug in than Micro USB.
When it comes to the ESC board, BLHeli_S has almost the same capability as BLHeli_32 when you flash Bluejay firmware, it supports bi-directional DShot and RPM filter, also custom startup tones as well. The main downside is that you can’t use higher or variable PWM frequency. So you are not compromising too much performance using the cheaper BLHeli_S ESC over BLHeli_32.
How To Use
Here’s the wiring diagram.
To power receiver and GPS, I’d recommend using the 4V5 pad instead of the 5V pad. These pads can supply power with the LiPo unplugged. This allows you to configure/test your receiver by connecting the USB cable without LiPo, and get a GPS satellite lock before powering up the quad. The 5V pads only have power when you connect the LiPo battery.
If you are pairing the F405 V3 FC with the SpeedyBee BLHeli_S 50A ESC, make sure to set the current sensor scale to 386 and Offset 0.
You will need a decent SD card for Blackbox logging, see my SD card recommendations. Betaflight firmware requires the type of the microSD card to be either Standard (SDSC) or High Capacity (SDHC), so extended capacity cards (SDXC) are not supported (Many high-speed U3 cards are SDXC). Also, the card MUST be formatted in FAT32 filesystems. So basically, you could use any SD card smaller than 32GB, but Betaflight can only recognize 4GB maximum, any additional storage would be wasted.
The Boot button has two functions. When the FC is off, by holding down the Boot button and power up the FC will put it in DFU mode, this is used when the FC has trouble flashing firmware. When the FC is powered on, the BOOT button can be used to control the LED strips connected to D1/D2/D3/D4 solder pads. By default, short-press the BOOT button cycles through the LED displaying modes. Long-press the BOOT button switches between SpeedyBee-LED mode and BF-LED mode. In BF-LED mode, all the D1-4 LED will be controlled by Betaflight firmware.
Official Manual (link provided by Speedybee): https://store-fhxxhuiq8q.mybigcommerce.com/product_images/img_SpeedyBee_F405_V3_Stack/SpeedyBee_F405_V3_Stack_Manual_EN.pdf
Build Log
This stack is going into my next build, I will be sharing the build log along with some PID/filter tuning guide: https://oscarliang.com/how-to-build-fpv-drone/
29 comments
Greetings, please tell me what could be the problem, speed bi pilot F405 3V, the problem is the following, so only under “Inav”.
1. The motor control protocol is not selected, or rather, it can be selected, but after saving and reloading it again becomes a “multishot”
2. The OSD does not work properly, it flickers, some values are not displayed at all.
But the worst thing is that this miracle is absolutely uncontrollable, yesterday there was an incident, I assembled it and set it up, everything seems to be regular, armed (by force, satellites do not catch in the apartment) when trying to take off (lightly raised the gas stick until the motors started to rotate) this is a bastard like a combat helicopter at full speed with a turn on a 6c battery flies into me and unfigures the appa, well, it got a little on the hands, the strangest thing is that it did not immediately become disarmed. This happened only with the “Inav”, on the “Betaflight” everything flies well.
mine on BF4.4 refuses to behave on BlueJay esc with bidirectional dshot and rpm filtering, angry roll of death after a few seconds of flight, hovering and steady climb out at 45% throttle, both same? go back to BLHeli all ok again?
Mine is working fine. Do you have blackbox log of what happened?
I also used bluejay and it falls to one side with bidirectional dshot and rpm filtering on had to go back to stock firmware but can’t stand not having bidirectional dshot and rpm filtering.
To get rssi & telemetry when using a FrSky R-XSR do you solder the wire on the “Uninverted SPort” pad of the rcvr and any available TX UART (TX3) pad? I had no issues binding the rcvr to the transmitter. Stick and switch inputs work fine using SBUS, but I’m not getting any rssi info on my Radiomaster TX16s MkII, even after attempting to “Discover New Sensors.” on the telemetry tab.
Hi guys , I have this stack and in live view there are voltage glitches. I have never had this with any stack. I fly DJI o3 and Caddx Vista. o3 and caddx same problem connected via the DJI connector.
Do you also have the problem and a solution? Greetings Mike
Hello Mike, I also use the combination SpeedyBeeF405-Stack and DJI O3 on the 9V BEC on a copter and I don’t know what you mean. If you have problems, maybe connecting the O3 or Vista directly to BAT (max.6S) will help you. Greetings from Rudi @RudisFPV (YT)
NOTE: with the old original DJI AirUnit this ONLY works up to a maximum of 4S!
.
Hallo Mike, ich nutze auf einem Copter auch die Kombi SpeedyBeeF405-Stack und DJI O3 am 9V BEC und weiß nicht was du meinst. Wenn du Probleme hast, hilft dir vielleicht die O3 oder Vista direkt an BAT (max.6S) anzuschließen. Gruß vom Rudi @RudisFPV (YT)
HINWEIS: mit der alten originalen DJI AirUnit geht das NUR bis max.4S !
How do I select motor KV etc which I connect to this ESC ?
I explained which KV you should choose here: https://oscarliang.com/best-motors-props/#What-Motor-KV-Should-You-Get
You can use any KV motor with this ESC as long as it meets the voltage and current requirement. This ESC should work with most if not all the motors out there for 5″ fpv drones.
One ESC is not working…
Speedy Bee don’t answer to my messages… Impossible to use warrantly…
Note: I am experienced, it’s not my first build. I don’t know what to think about this brand…
It’s chinese new year most people are still on holiday (they all get one week or two weeks off i think), and they probably have a ton of messages to reply to. Wait a few more days perhaps.
How come there wasn’t a need to use PDBs? I’m new to this and trying to learn. I have seen other builds that use PDBs with a stack. Is the PDB built into this stack? If that’s so, what specs tell you that when buying a stack?
PDB is now commonly a part of the 4in1 ESC.
Is this FC stack compatible to INAV?
Mine using Bluejay can’t spin the motor when armed or manually rising throttle in motor output (multishot).
How did the build go? I also purchased this stack for a build but having trouble tuning it….PID toolbox is constantly showing overshoot and in Blackbox, gyro is lagging…I hear ticking in the motors too…
I’m down to 0.8 on MasterSlider with FF set to 1.2…I’ll try this out and check back later….
See my build here using this stack:
https://oscarliang.com/how-to-build-fpv-drone/
For PID tune scroll all the way down.
Hello Oscar, I am a complete noob. I have this stack and a Spektrum DSMX Satellite receiver SPM 9645. I have it soldered to the SBUS pad, ground, and 3v3. I can’t get it to work.
Can you tell me the Betaflight settings?
I never use Spektrum stuff, but I think you should solder your receiver to a spare UART (TX and RX pads, NOT SBUS pad).
I used this stack for my last build but in the osd the altitude value flashes all the time I can’t figure out why. do you have any advice?
Hello Oscar. I have this stack. Quick question. I know the gyro update frequency is locked so I can’t change that. What should I have my pid loop frequency set to if I’m running d shot 300.
Leave PID loop frequency at 3.2K is fine, same as gyro sampling frequency.
Will F405 V3 handle inverted sbus (R-XSR) receivers natively,
it has a dedicated sbus port.
Do you know which uart is is? I assume 2
Yea, UART 2 – they dedicated this UART for receivers.
Made three Builds with this Stack…. One was suspiscius after the Lipo LEDS on the FC dimmed out after connecting first time USB and dont able to connect via Bluetooth
Smoke stopper startet flashing when pluging in a lipo…
ESC Puffed witouth FC and Smoke stopper connectet…
Dont trust this FC anymore but will buy another Speedybee Stack.
So my Ratio is 1:3 to this time of date
I may add that… I’m new to drone world (but not new to electronics). Got this FC as my first one. I thought doesnt need the included capacitor as had anything connected but FC+ESC board, right? Wrong. I plugged in 12V in ESC board battery pads what produced a large spark. It doesnt produce sparks with the included capacitor but still my Melcher power supply red led blinks once (indicates _huge_ current spike). I think this is weird. Can be anything, like a short (when ESC firmware still loading, floating states causing a short? Anything else?). I don’t know but it really looks weird.
Usually it’s the other way round (current spike when capacitor is connected). Get a multimeter and smoke stopper to check the 4in1 ESC. I describe how to do it here: https://oscarliang.com/how-to-build-fpv-drone/#5-Testing-ESC-and-Motors
Hola saludos tengo problemas para flashear de fabrica la fc alguna recomendación por favor ya seguí los pasos del manual y nads