Hi all
EDIT / TL;DR / Solution: I think the calibration is working. I checked my measurement adaptation using the Power Statistics in Linux Mint and this is the new one now:

Seems like it's adapting, it's just slow. If this doesn't work, I'll update again. Cheers!
I just changed the external battery of this T470p I bought. The old one was at about 70% battery life and was smaller at 4.4Ah. New one is around 6.34Ah.
The battery lasts almost double the time now so it's great, but, the % reading in Gnome Power Manager (bottom right tray) is way off. The laptop dies at around 40%. Ofc the estimated time left is also way off.
I did buy the battery for around 30% cheaper than I find it here from Aliexpress: https://www.aliexpress.com/item/32637096491.html (perhaps it's just weird, but it does last longer)
I tried
- Drained the battery by playing youtube then recharged over night.
- Installed and recalibrared with TLP (let it discharge with TLP running, plug in while off, leave it plugged over night) (this uninstalled power-profiles-daemon - I later uninstalled TLP and reinstalled that package).
- Checked BIOS for a battery recalibration utility. I found none unfortunately. I looked everywhere including Config (there was no Power menu there). I also looked in the hardware diagnostic software that I can access instead of booting into BIOS. I believe the key was F10.
- Checked the settings app, nothing.
- Checked online, everyone says use TLP or discharge manually repeatedly without charging partially in between.
This is what my discharge profile looks like

Laptop with old battery next to it:

These are my battery readings
marin@ThinkpadT470P:~$ acpi -i
Battery 0: Discharging, 84%, 04:45:31 remaining
Battery 0: design capacity 6282 mAh, last full capacity 6282 mAh = 100%
marin@ThinkpadT470P:~$ sudo tlp-stat -b
***
TLP 1.6.1 --------------------------------------------
+++ Battery Care
Plugin: thinkpad
Supported features: charge thresholds, recalibration
Driver usage:
* natacpi (thinkpad_acpi) = active (charge thresholds, recalibration)
Parameter value ranges:
* START_CHARGE_THRESH_BAT0/1: 0(off)..96(default)..99
* STOP_CHARGE_THRESH_BAT0/1: 1..100(default)
+++ ThinkPad Battery Status: BAT0 (Main / Internal)
/sys/class/power_supply/BAT0/manufacturer = LGC
/sys/class/power_supply/BAT0/model_name = 45N1738
/sys/class/power_supply/BAT0/cycle_count = 3
/sys/class/power_supply/BAT0/energy_full_design = 74050 [mWh]
/sys/class/power_supply/BAT0/energy_full = 74050 [mWh]
/sys/class/power_supply/BAT0/energy_now = 59250 [mWh]
/sys/class/power_supply/BAT0/power_now = 13722 [mW]
/sys/class/power_supply/BAT0/status = Discharging
/sys/class/power_supply/BAT0/charge_control_start_threshold = 0 [%]
/sys/class/power_supply/BAT0/charge_control_end_threshold = 100 [%]
/sys/class/power_supply/BAT0/charge_behaviour = [auto] inhibit-charge force-discharge
Charge = 80.0 [%]
Capacity = 100.0 [%
I checked, I do not have an internal battery installed.
I also repasted the CPU and GPU when I opened it.
Thanks again for helping me pick a distro in my other post! Everything is up and running nicely with Linux mint. I even set up Lutris, Steam, and a bunch of utility apps. I still need to set an FPS limit somehow because this thing PULLS in old games.
PS I promise that trackpad is clean lol, looks so dirty in the piciture.
Psu cable goes in psu :-D
turns on
finds out that cable was in fact not from that psu