3D accel needs calibration, but only on battery?

Hi there

I have been doing some rework on my hexa copter, as suggested on this site. But i havn’t been able to have a really stable and reliable flightcontroller since.

My problem is, that it keeps saying i need to calibrate the accelerometer. But i have done that. Today i tried to reinstall ardupilot 3.5.3 from scratch, inserted all my parameters and went to the flying field. I started by calibrating the compass and the acc. outside, in the middle of the landing strip, without any kind of magnetic interference except my laptop, which was sitting 1m away (i have been calibrating a lot before, and it has never been a problem). Everything has been fine, mission planner confirmed everything is fine, i can reboot, i can do everything i want to do. I take off, fly 1 battery, land, change battery and the problems start.

Often the Here GPS is flashing the blue-red cycle a second or two, and then it starts flashing yellow. It never goes to green or blue… Often i can disconnect the battery, and connect it again, and it works. Whenever i fly the second or third battery, it will never get out of the yellow state. Whenever i connect the laptop, it says either i need to calibrate, of compass inconsistency.

Sometimes i can calibrate from scratch, and it works over again, with one or two batteries… But i really don’t want to calibrate it every second flight tbh…

Today i went home after only two batteries, because i wasn’t able to get it calibrated in the field, and when i got home, it did the same thing…

But then i tried to connect and let it power ONLY over laptop, and it works every time!!! Why is this? I am using Mauch power supply, but i don’t think this is the problem?

Its a pixhawk 1, mauch 200a psu, here gps on a DJI frame. It has only occured after AC 3.5…

Any ideas??? Thanks.

No one?? Really struggling with this problem? :frowning:

Check that the GPS/Compass module is on level and the arrow of the GPS module coincide with the arrow on the FC.
You can also try with the internal compass disabled (un-check in MP) , look if the copter really point to north when the arrows point to north.

Can you post some log files for anyone to have a look at?
It’s a bit hard coming to any conclusion from your description as there are may things that may affect this.

I’m having the exact same issue. However the power source doesn’t matter. It must be a bug in 3.5.3.

Bernardo, thanks for your reply, but as i mentioned, it works perfectly. It just doesn’t work every time… Yes, the compass/gps is level, and is in the right direction as the FC. Everything is mounted as it should, and everything has been working for 250 flights now. But not any more.

I would love to. But as you know, the flight controller only logs, when it’s armed, and i am not able to arm it, as it require me to calibrate. Whenever i can arm it (because i just calibrated it, or formatted it), the logs are absolutely fine…

If you go into your parameters for Logging you can set the logging to log while disarmed.

Okay. I didn’t know that. Will do that! Thanks!