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Scruff1026

macrumors member
Original poster
Sep 26, 2022
61
10
Last night was the second time this happened. Laptop was just sitting in the background when I noticed it was off. Then I remember this happened about a month ago. Had to plug it up and when it came on the battery was at 1%. Everything looks fine as for as the battery goes on coconut battery as well as on the macOS battery status. Any idea on why this would just start happening out of nowhere. Laptop is lightly used and everything is up to date with the latest macOS. Im attaching a picture the red is where it shut off and showed 1% when it came back on. IMG_2586.jpeg
 

JPack

macrumors G5
Mar 27, 2017
12,591
23,399
Defective pack. If the aged battery can't output energy fast enough (high internal resistance), the computer will shut off. This is similar to iPhones with old batteries that shut off unexpectedly. It's not due to capacity but internal resistance.
 
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MacCheetah3

macrumors 68020
Nov 14, 2003
2,106
1,079
Central MN
Can't calibrate if Im not getting the low battery warning right?? It just shuts off.
Calibration is exactly for that reason, (re)determining what the current capacity and low voltage points are (as they change over time).

iFixit’s summary:

The fundamental problem is that there’s no reliable way to know exactly how much energy a battery holds at any given moment. (It’s an electrochemical storage system that is always changing and decaying, and never behaves exactly the same way from one charge to the next.) About the only reliable way to gauge it is to fully charge the battery, then fully discharge it and measure the difference (a.k.a. coulomb counting). Obviously, we can't do that every time we want to check the battery level, so we have to use indirect methods—storing all kinds of usage data and using that to calculate an estimated % state of charge from moment to moment. Over time, that calculation tends to drift and become less accurate. And on a brand-new battery, there’s not really any good data to work with, so the model will be way off. Calibration helps keep estimates accurate by setting new “full charge” and “full discharge” anchors in the battery management system so it doesn’t have to guess. We're still playing Pin the Tail on the Donkey, but calibration tells the battery management system, "Hey—the donkey is over that way."

  1. Charge it to 100%, and keep charging it for at least two more hours.*
  2. Unplug your laptop and use it normally to drain the battery — save your work more frequently as the battery percentage gets lower.
  3. Keep your laptop on until it goes to sleep/shuts down due to low battery.
  4. Then, again, charge your laptop uninterrupted (i.e., don’t disconnected the charger) to 100%.
* You can often observe this process in apps such as coconutBattery where you may see Current Charge increase beyond the (previously marked) Full Charge Capacity or charging stop before Current Charge reaches the Full Charge Capacity.
 
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