Hi there, I expirienced something similar with my new pocket. The first time it loaded to 80% and stopped and i unplugged it. at 20% i had a hard shutdown going to reboot. i put it back on power and had a hard shutdown going to reboot at around 80%. Those Numbers looked to me like a battery-saver function going crazy.
Now… i’m not sure, as some days have gone by and i fiddled around - i think Upower was there by default…
Anyway - i found a post from josh mentioning editing /etc/UPower/UPower.conf and changing following options to remove safety belts, which he described very nicely:
AllowRiskyCriticalPowerAction=True
CriticalPowerAction=Ignore
For me it did the trick. since then, there were no unexpected reboots.
What I also expirienced after that: the battery or sensor-values seemed somewhat uncalibrated. i powered it up to 100% and let it run dry - the last 1% did last very long. now it seems the battery values are ok and the runtime is now around 3 - 4 h, with a full-load voltage of around 4.1 V.
I’m running the rk3588 with preinstalled debian and sway btw. and i don’t need powersaving functions at the moment.
Here is the mentioned Post: Battery life tests with RK3588 - #15 by josch