AttoPilot 180A Voltage fluctuation

Hi all!

When stepped up to 4S from 3S on same hardware, my voltage reading from PixHawk is jumpy all over. Been trying the whole evening with entering both measured voltage and just tampering with the Voltage Devider constant (Latter method worked fine with 3S to get an accurate readback from PixHawk) As it is now, a steady 16.64V on the multimeter gives all from 10V to a spike of 35V…

I’ve also been moving the adjacent BEC around and even disconnected it, in case it caused some induction or interference, but no difference.

See attached Battery voltage plot to get a clear picture of my problem.

Any ideas what might be wrong?

Hold it! Found a broke wire…