Newly replaced battery - shows “X”

Hello,

The first set of steps from Reset the SMC of your Mac - Apple Support are steps of what to do before resetting the SMC. The next set of steps are for resetting the SMC, which is what to do if the issue you're experiencing persists after following the first steps.

Method 1: (for clarity)

1. "Shut down your Mac, if possible.
2. Press and hold the power button for 10 seconds, then release the button.
3. Every Mac has a power button. On laptop computers that have Touch ID, press and hold Touch ID.
4. Wait a few seconds, then press the power button to turn on your Mac.

Method 2: (for clarity)

If the issue persists, reset the SMC:

1. Shut down your Mac.
2. On your built-in keyboard, press and hold all of the following keys. Your Mac may turn on.
3. Control  on the left-hand side of your keyboard
   • Option (Alt)  on the left-hand side of your keyboard
   • Shift  on the right-hand side of your keyboard
4. Keep holding all three keys for 7 seconds, then press and hold the power button as well. If your Mac is turned on, it will turn off while you're holding these keys.

What is the difference specially between Method 1 and Method 2 ?

I thought pressing power for 10 seconds may have something to do with resetting T2 chip specifically, while command-option-shift does the SMC reset, but I can find no evidence of the 10 second power button responsible for T2 specifally, but it be good to know.

Let’s get a better view of things, install this gem of an App CoconutBattery post a snapshot here so we can see too.