Pixhawk Hexacopter Crash - Brown out?

Hello all,

I’ve just recently finished up my Tarot 680pro and decided to use a pixhawk and leave my apm 2.6 in my quadcopter.

Maidened yesterday to test out all the flight modes, and everything was working great. Until I initiated at RTL then back to AltHold and Stabilize intending to land it manually. That’s when the hexacopter lost power and crashed into the ground.

I had a look at the logs and how to analyze them on the arducopter wiki. I’m drawn to the conclusion that I experienced a brown out based on what was written there.

If that is the case, I’m trying to figure out what I can change to ensure this doesn’t happen in the future.

I’m using a clone power module which may be the cause in itself?

I have 30A simonK escs plugged into the pixhawk and I left all the + and ground wired on as well as I read that this provide backup power should the power module fail.

If anyone can have a look at my logs and give me a second opinion and/or suggestions to improve my setup I would greatly appreciate it.


I also just tested my power module. I believe it is faulty as there is no 5V supply going into the Pixhawk. This means that the Pixhawk was being powered by the ESC BEC.

From what I understand, if the Pixhawk is being powered by the ESC BEC, it’s the backup supply, and has a high failure rate with being powered solely with this method.

I will order a proper power module and test it beforehand to verify it is working.

If someone could still give me an opinion if my analysis of the logs is correct I would greatly appreciate it.


What was the voltage that your BEC was supplying the Pixhawk? Any voltage over 5.5vdc can cause the Pixhawk to reset.
Also did you install the 5.6vdc zener diode per these wiki instructions: http://copter.ardupilot.com/wiki/common-autopilots/common-pixhawk-overview/#powering ?

jamblor, your assessment is probably correct. The Pixhawk stopped logging while it was still 10.5 meters up, which is a pretty classic symptom of a power failure. I’ve seen a number of clone Power Modules that don’t include the sub-board that actually produces the 5 volts necessary to run the APM or Pixhawk. It’s quite possible noise from one or more of your ESCs could have triggered a Pixhawk reset. As TCIII pointed out to you, if you add the zener diode outlined in his link, that will go a long ways towards eliminating any noise.

The best setup you could have for this would be to install a “real” Power Module as your primary power source and only one of your ESCs +5 volt leads, along with the zener diode as a backup. The reason it’s not considered a good idea to connect all of your ESC + leads is that they all will be at very slightly different voltage levels and may “fight” with each other.