ESC Got Burned when BEC Connected to Rail

Hello everyone. I have connected 4 ESCs to Navio 2 according to docs which states only 1 BEC should be connected. I have cut the red wires of my 3 ESCs and connected them. So only 1 red wire was connected to servo rail. It was the number 3 ESC. (Docs shows as only ESC number 1’s red wire is connected but I don’t think connecting other ESC’s red wire would be a problem)

After this, I attempted the turn motors and ESC got burned. Even smoke came out of it. This was the ESC which it’s red wire (BEC) connected to rail. I thought it was faulty ESC/Motor and replaced ESC with new one. I was going to turn the motors once again but before turning them I checked the ESC by touching it and it was extremely hot. I barely kept my hand touching it. I didn’t event turn any motors. Just gave the power to the setup and that’s it. This ESC’s red wire (BEC) was also connected to rail. Then I wanted to check if it is going to get hot again when I cut red wire and tried it. And… ESC were no longer getting hot…

So, what I suppose to do? I am connecting only 1 ESC’s red wire (BEC) to rail but it makes ESC get extremely hot. Even burns it when some time passes. How I suppose to power the rail?

Hi Ege,

Welcome to our community forum!

We recommend connecting only one power wire from ESC to prevent potential overheating. In some cases, it’s possible that the current could flow from an output of one BEC to another. This might lead to excessive heating.

You’re right. It could be any of the selected ESCs.

Have you checked whether your ESC can handle the selected type of battery voltage and motor specs?

Have you checked whether your ESC can handle the selected type of battery voltage and motor specs?

Yes, my 40A ESC supports 2-4S battery and I am using 4S battery as well. When the ESC got extremely hot, there were no motor connected to it. Only other 3 ESC had motors connected to them but none of motors were spinning so there were almost (except idle ampere draw) no ampere draw on the system. I have flew my quadcopter many times by the way and had no issue with ESCs as well. They didn’t even get hot.

Hi Ege,

Have you used Navio2 for those flights or some other flight controller? It’s essential to understand at what point the issue appeared.

I have used Navio 2 for flight, yes. I am unable to find the issue to be honest. Everything is done according to docs. But when red wire of BEC connected to rail, it makes ESC to get extremely hot, you can’t even touch it. I don’t think it’s an issue with ESC specs. Because like I said, I did able to make successful flight many times.

Hi Ege,

What is your hardware setup overall? Please post close-up photos of your drone. Also, please share the exact make and models of the third-party hardware.

My specs are:

  • Leopard-Power 4200mAh 40C 4S Li-Po Battery
  • Raspberry PI 4 (4GB) Model B
  • Navio 2
  • Tallysman GPS Antenna
  • FS-IA6B Receiver
  • 4 x Brushless (brand) 40A ESC
  • 4 x SunnySky R2207 (2580KV) brushless motor with 5041x3 prop


All connections are done based on docs and I am able to fly the quadcopter on stabilize. (Haven’t tried other modes yet.)