ESC Overheating, Wiring Problems

[Danchat]

Hello, I'm a newbie to the field of fixed wing models and flight controllers, and I'm looking for some help with a wiring issue. I have a finished model of the Flite Test Explorer and I had purchased the Pixhawk 4 to use as a flight controller, but I've been having difficulties. When I followed the wiring guide, my ESC (BLHeli 30A BEC 2a 5v, LiPo 2s-4s, using a 3 cell LiPo battery) began to overheat so much that the black wire came disconnected from the solder pad (see image below, the ESC is the thing to the right). Was there something up with the ESC's compatability with the Pixhawk? I know little on the topic of volts and amps, so was there some sort of short circuit/overpowering of the ESC?

Here arethe only instructions that came with the Pixhawk 4 on wiring:

Any help would be greatly appreciated.

 

[ElectriSean]

It looks like you are trying to power the ESC through the BEC, which will cause all kinds of problems. Where are the larger red and black wires from the ESC connected? They should go to the B+ and B- pads on the FC. The smaller red wire is for the ESC's 5V BEC. SInce it looks like you are using an external BEC, you should disconnect it and cap it off.

 

[Arcfyre]

ElectricSean nailed it it seems. It looks to me like the two larger gauge cables coming off the ESC in the top right corner of your picture need to be soldered to the pad on the bottom right of your FC (labelled ESC motor 1 in the diagram)

 

[Danchat]

Thanks for the help. There is no "B-" pad, but it seems like the black and red wires that normally connect to a LiPo battery go to the "GND" and "B+" pads respectively. Then the servo's yellow wire goes into the M1 socket... that will leave the other two (red and brown) cables unused, so I should "cap them off"?

 

[ElectriSean]

The brown wire is fine on the ground pad, the red should be disconnected. To cap it off, I just cut the wire so that none of the conductor is exposed and put shrink tube at the end extending a few mm past the end. Alternatively you can use that red and brown in place of the external BEC and save that for another project.

 

[Danchat]

The brown wire is fine on the ground pad, the red should be disconnected. To cap it off, I just cut the wire so that none of the conductor is exposed and put shrink tube at the end extending a few mm past the end. Alternatively you can use that red and brown in place of the external BEC and save that for another project.

Is it possible to attach both the black and brown wires to the pad? The black wire is a bit big, so it might not fit on there with the brown one already attached.

 

[ElectriSean]

The ground pads should all be common, so no real need to share in this situation. If you run into a build where you have to share, I recommend soldering the larger wire first, then adding the smaller on top. If you properly tin the small wire you can get it to stick without reflowing the whole joint.