okay.
but the question for my case is:
before Aug 2019 when I shut down my SP4 there are no battery drain when off . Also for long period.
after Aug 2019 (firmware upgrade) my SP4 lost 15% per day when is off.
I know that some problem is aging batteries but this problem can affetct battery when on... reporting bad percentage... ecc! when the device is OFF it must be OFF!
I've an old IPAD2; the battery is ok after 8 years and when is OFF the IPAD is OFF!!