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.
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.