Receiver low voltage alarm

Hi everyone ,

Brand new here. And brand new to the multi rotor world.
I purchased a small quad kit that came with a CC3D controller.
Built it , flew it. Everything worked great.
Now I have purchased an APM board with gps and all the goodies.
Installed it last night , installed the latest firmware.
My quad was previously wired to power the controller through one of the ESC’s. So I left it that way instead of doing a complete tear down and rebuild and rewiring job.
The instructions show to short a jumper on the back of the controller board to power it through the ESC. I did that.
Now my radio tells me my receiver is getting low voltage. I removed the jumper and powered the board with the supplied power board and harness. No low voltage alarm this time.
Why does it give me a low voltage alarm the other way? It didn’t do that with the cc3d board.
Someone on another forum told me there is diode in there that drops the voltage. ??? Why would that be ?
I would like to power through the ESC. As the quad is built and configured for that.
But if I have to do a full tear down and rebuild. I will reluctantly do it.

Thank you for any help or advice

Try here:

Just read everything.
First, linear BEC not recommended.
Second , 2 amps recommended.

So did some more digging. My ESC’s are 12 amp units with only a 1 amp linear BEC. So both things working against me LOL .

I guess I have a couple options. I can pull power from a couple of the other esc bec’s to help eliminate any voltage drop. Or Redo the quad, add in the power board and power everything that way.

I guess I will do option 2 and start over. Rewire and reposition everything.