Both Andreas and I had the same problem... fortunately he had it before I did, and had figured out a workaround.
Problem: when powering up, not all motors will spin.
Workaround: apply power to the APM2 before attaching the main battery. You can do this either via USB or by attaching a spare battery/ESC to one of the output lines. As soon as the board boots up, hook up the main battery and remove the second battery.
Comments
Any updates on this ? I am also facing the same issue.
No Real answers I'm afraid, but you may find the following 2 posts interesting.
http://diydrones.ning.com/forum/topics/hexacopter-twitching-in-flig...
http://diydrones.ning.com/forum/topics/apm-2-5-only-boot-via-usb
The video I have uploaded, is that what you are experiencing ?
Hi All,
First of all, APM 2.5 running latest firmware on HexaCopter.
I too have an issue where I have calibrated the radio and ESCs a number of times.
I have then taken the Hexacopter to the field, connected the LiPo, waited for GPS lock and then on throttle up, sometimes only a couple of the motors will spin. I will disconnect the power and try again, sometimes different motors spin up.
I have then brought it home, done no more than plugged it into USB, tested throttle and all six motors will spin fine.
Disconnecting USB and running normal LiPo and all 6 will spin without issue.
The hexacopter is a new build, but it has failed twice in the field powering up, but doesn't when it's on my desk.
Any suggestions how this can be resolved without stripping the ESCs and reprogramming.
For information the ESCs are jDrones 30s.
Many thanks,
Steve
We've seen this issue with a small number of ESCs (different brands have different firmware, and handle startup sequences differently). We're working on a startup PWM sequence that may handle these outliers better and that patch is currently in the working code and should ship with the next public release.
BTW, the reason why these troublesome ESCs would work when you start under USB power, but not LiPo is that when you start with USB power, the ESCs are not powered. So the APM boots up first. By the time you plug in your LiPo and power the ESCs, the APM is outputting regular PWM, and past its own boot sequence.
I have this problem on APM 2.5. My motors will only spin up if I boot my APM using USB before plugging lipo in. I can arm/disarm no problem but they just won't spin up unless I pre-boot.
I've got some different ESCs on the way, hopefully that will resolve the issue.
On my Y6 I have 4x Hobbywing 30A esc's, and 2x the same brand and tech but they have two capacitors instead of one (newer model)... I have this issue with the two new model ESC's on channel 5 and 6. In CLI under setup/motors they all spin except these two. I calibrate them again.....same problem, even with connecting the lipo after USB and motors command. If I start up without MP and just lipo to fly, they arm ok. Am I missing something ?
In my case: it always happens on the back left motor, and sometimes on the back right or front right motor. The front left motor has never had a problem. I'll try switching the ESCs to see if the problem is following particular ESCs around.
To others who are seeing the same issue, is it also happening on just one motor? Does it happen on any motor besides motor 2?
Yes, the same configuration works well with an APM 1. Still investigating, hope somebody else might have some insight as well...
Michael: different motors; some will work periodically; one always stays off.
Chris: just tried disconnecting the power from three of the ESCs, no joy, symptoms are identical. (Although now I understand the reason to have power from just one, so that a voltage differential between two BECs doesn't cause a continuous power drain).
I'll make a permanent fix later, but for testing I just made these connectors and put them between the ESCs and APM:
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1
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2
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