MacBook Pro 16 - battery drop during off

[SwiftyAlek]

Hey guys.
I have noticed strange thing with my M1 Pro MBP.
I've shutdown them Friday afternoon (around 14:30 PM) with 100% charged.
Today evening after power on I've noticed that battery was charged only 88%. It is 12% loose energy during around 48 hours. What could happen?

I have enabled optimized charging.

Does anyone noticed similar issue?

 

[Sanpete]

The optimized charging function may be discharging the battery until it reaches 80%, which is normal if you use it plugged in most of the time.

Or it might be something it's doing while it's supposed to be sleeping. Some processes are supposed to do that, like indexing.

 

[Honza1]

12% in 48 hours? Not that unusual. My 2017 MBP usually looses 6% in 24 hours. Depends on battery age and if you have the Power Nap enabled. May be other things...
Battery itself discharges from 100% even if you power system down with time. Depending on its state, discharge eventually slows down. That is why they ship batteries partially charged only, at 100% they do not hold the charge well anyway. At 40 - 80% they loose charge much more slowly.
Power Nap wakes computer every few hours to do maintenance, so it takes power to do so. If you have iStats menus, you can check on cpu and see, if there are bursts of cpu activity while it is sleeping.