XPS 15 9570, battery drain when switched off

I'm having the exact same problem on my XPS 15 9570 (out of warranty on November 3, 2019). I shut the device down using the start menu option at over 80% charge and when i turn it back on it's below 10%. The same thing happens on sleep mode. It is very annoying! I haven't always had this problem, it started a couple of months ago, probably after an update.

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