Chosen Solution
So I replaced my A1502 battery a couple of weeks ago and everything seems to be working smoothly. However, when the battery drains to about 4%, the machine abruptly shuts down. When I press the power button, instead of the laptop recognizing the battery is low and flashing the battery low symbol, it tries to boot and shuts down about halfway through the progress bar. This is a new problem for me. I have tried resetting the SMC, PRAM, and tried numerous battery calibrations. Is this intended behavior, or is my unit defective? Should I worry about battery health going forward?
Edit: added coconutBattery screenshot
Here is a screenshot of coconutBattery while charging from 0% Update (06/14/2022)
Here is a screenshot after over 10 hours of uninterrupted continuous charge. Something to note is that the machine occasionally gets choppy on low battery which may be a power output thing.
Edit: screenshot from when throttling starts to occur.
OK, Now let’s plug in the MagSafe give it a few minutes and take a fresh snapshot so we can see it under charge. If its charging give it a good 10 hours turned off, then take one more snapshot. Let’s see how it charges and if it gets to a full charge. I’m thinking we may need to do a hard SMC reset. But I want to be sure before we go through the process.
Batteries can trip off even with good capacity data. Capacity and peak power output are different parameters and mostly independent from each other. You most likely got a battery that has adequate capacity but only works on low output, during high output, high internal resistance causes the output voltage to drop sharply and the computer just trips off.
