why 'Charging on hold' , 'On Hold 80% battery'

[ewu]

16 inch M5 Max Macbook pro, Mac OS Tahoe 26.4.1. It always drains battery from 100% to 80% and on hold at 80%.

My Dell U2723qe provides 90W input from usb c to MBP, at beginning I think may be 90W is not enough and mbp didn't take magsafe 3 power
Then I change to hdmi cable to connect and left magsafe power only. but battery still go down.

adjust many settings such as battery/weak/sleep.
however, it seems that MBP on purpose want to drain battery from 100% to 80%

I google and ask chatgpt, result is 'Optimised Battery Charging'

It’s normal and good! Batteries do not like being constantly charged to 100%

my macbook pro M2 pro with Mac OS Sonoma don't have such issues.
but it shows that M2 Pro battery only 84% health after 3 years usage.

so I suspect it is a new feature of mac os Tahoe 26.4.

I start to use macbook pro since 2010, totally > 16 years, none of macbook pro has battery issue.
why we require such way to `Optimised Battery`

 

[Basic75]

none of macbook pro has battery issue

Would you have noticed your batteries degrading slightly faster because they were often at 100% as an "issue"?

 

[ewu]

Would you have noticed your batteries degrading slightly faster because they were often at 100% as an "issue"?

my M2 Pro mbp battery is only 84% health after 3 years usage. battery will drain faster but power still acceptable in most of cases with battery only. I don't think it is an ssue.

After I turn off M5 Max macbook pro, it starts to charge battery based on power meter.
and then second day it starts to drain from 100% to 80% again.

it looks like mbp is a big iphone. charging after mbp shutdown and drain to 80% when mbp starts to do heavy duty.

I could turn off `Optimised Battery` , but will new stratedgy benefit battery health in long term?