MacBook Pro 16" 2019 battery capacity decreasing


macrumors newbie
Original poster
Feb 19, 2020
Hi folks,

I've bought a brand new MacBook Pro 16" 2019 about 3 weeks ago.
I use the laptop with power adapter connected but battery capacity has been decreasing on a daily basis very fast.

Full Charge Capacity (mAh):    8623

Health Information:
  Cycle Count:    4
The initial capacity of bq40z651 battery is 8790 mAh but I have 8623 mAh after 4 cycles only.

The capacity was 8638 yesterday. I've disconnected power adaptor and went for a sleep. When I woke up the capacity was 8623. So the battery lost 15 mAh when the laptop was in sleep mode. I don't know what tf is going on.

Do you think this is the hardware problem? I do so.

I believe I should bring my laptop to Apple service but I've decided to ask an advice here first.




macrumors 6502a
Sep 18, 2011
I think it would be better if you actually let the battery discharge and recharge a couple of times and not keep it permanently connected to power.

I believe this has a positive effect on both battery health and measurement accuraccy.

If you browse the forum you will find others that have had initial capacity a bit below nominal but things have corrected themselves after a bit of use.


macrumors 6502a
Nov 30, 2013
Do not worry about these tiny changes of reported capacity. They will drop quickly at the beginning to some stable level, typically. It is wild guess anyway. And, as stated above, these values will fluctuate.
It is a good idea to use system occasionally on battery and discharge to at least 50% sometimes. I try to use it on battery at least once a week. Battery needs some cycling.
While everyone agrees at least occasional battery cycling is good thing, how deep is disputed. Rechargeable batteries materials are actually damaged by deep discharge and therefore I prefer not to cycle below ~30%. But it is possible Apple keeps necessary reserve to prevent such damage in which case we should discharge occasionally to 0%. I just do not know and without someone with direct knowledge from Apple we may never know.
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macrumors newbie
Jun 25, 2020
Yo, any update on how your battery is now? I got a 13 inch 2020 (base model) like 2 weeks ago. Today, it is on 8 cycles and the battery capacity is on 98%.
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