Bangle.js 2 - Battery always 100%

Hi - thanks for looking into this and dumping the voltages. It sure looks like in your case the resistors fitted for the voltage divider are wrong. I have no idea how that one could have happened!

Really sorry about that, although I don't think it should affect your Bangle in other ways... I think the best fix would be as @andrewg_oz has done. Installing the 'Custom Boot Code' app and pasting in:

E.getBattery = function() {
  const lo=0.38,hi=0.48
  var b=Math.max(lo,Math.min(hi,analogRead(D3)));
  return Math.round((b-lo)*100/(hi-lo));
};

should properly fix the problem for you.