Hi,

I've just bought a SpeedyBee F405 V4 stack. I was wondering if I could use just the FC in my older build QAV250 instead of the existing OpenPilot CC3D FC? If yes, how?

TIA

So you have a set of a single esc's?  You will have something that looks like this.

So the thick red and black go to your PDB.



The other two wires, one of them goes to the motor pads (m5,m6,m7,m8) on the FC, the other to a ground pad.





Or you could wire them to the pads by the connector I think which would equate to M1,M2,M3,M4.

Some vids for an overview of the general way of doing it.




For the record no one builds this way any more (apparently).  I asked the same question a while back as I have 4x 20A individual ESC's I want to throw on a build for just doing it's sake, not because it's a good or bad idea or any other reason.  I had to garner the info myself as people were far from helpful.  but the gist of it, is as above.  Send the control wires from the escs to the motor pads on the SpeedyBee.

Hi,

Thanks for the great help. 

The only issue now is how to power the FC, because neither the ESC board is connected to FC nor the individual ESCs mounted on the build (except for the signal and ground wires). 

Pl comment if you have any suggestions. Pl specify the pad where to connect the power, and weather the power from one of the ESC can be used?

TIA

You have one good choice and there is another one, but use this one if you can.  

Use a PDB.  So you connect the ESC power to the PDB and the FC connects to the PDB.  That's the way i'd do it.  Obviously buy a PDB that can deliver the power you need.

Then use the connector that is for the 4in1.  Two of those pins will be for powering the FC, solder them to VBat and GND.  The ones I circled in the image.

Thanks a lot

So the PDB I will be using is a Matek Micro PDB. It's rated for 20A per ESC. Most Matek PDB's are discontinued. There are some Fakes around as well, so be aware. There are subtle differences between the originals and fakes, mostly in the typeface/font on the boards. See this link for examples.

Each of these ones also come with a BEC, so you can power the VTX and Control Link straight from them.

Matek 20A



Matek 25A



If you need bigger than this I don't have the experience to make suggestions. There are a couple of guys on here that might be able to. But my own research was based on a max of 25A per ESC.