DCM Yaw inconsistent by 68 deg after battery change

[wicked1 (S)]

I would try the in flight compass learning.
https://ardupilot.org/copter/docs/common-compass-setup-advanced.html
towards the bottom of that page, or:

Testers needed for in-flight compass learning

[image] I would like some testers for a new ArduPilot feature - in-flight compass learning. This is a feature that was originally developed for the SkyViper quadcopter, but can work with a wide range of vehicles (planes, copters, helicopters, rovers, boats etc). It avoids the need to do a compass calibration dance, which is particularly useful for large vehicles. The pull request is here: I am also happy to provide pre-built binaries if you let me know in the comments below what flight c…

I set mine as a switch on my transmitter (I didn’t see this method mentioned in the docs, but it is in the forum post). Then fly up high away from any sources of interference, flip the switch to learn the new offsets, and it just takes a minute of flying around for it to get a great calibration.