Strange power reading on Yoda

[rossdv8]

This is NOT a complaint, nor a report about a bug.

I booted my Lenovo Yoda this afternoon after about five weeks sitting idle. It had been charged after the last use, and on boot it showed a battery Level estimated at 94%. I wrote a few lines, recording state of charge and what I was about to do, then I updated software. Battery level after 10 minutes was now 89%. It usually gets about 4 hours on a charge running Mint 20.2, so that wasn't too surprising. Since there were kernel updates and similar exciting goodies, I rebooted.

After reboot, I had an estimated battery level of - wait for it . . well, goodness me ! 6% - 15 minutes remaining.
I noted that in the log and rebooted again, Justin Case it was a reading lag or glitch or something.
After this second reboot, the total 'on' time had been 20 minutes and Battery remaining was 5% - 12 minutes.
I did a Shutdown.

So I apparently lost a bit over 90% charge in 20 minutes that included a download from Mint mirrors and about a paragraph of typing in LibreOffice, plus one reboot after the kernel changey thing, then a final reboot to check if the low power reading was still showing.

I am not suggesting Mint caused the huge power drain. I am wondering though, about the initial 90+% reading on boot, that was simply dropping 5% in ten minutes. Obviously it is something in whatever the Linux Power Manager uses to guestimate battery charge state.

So I'm curious as to anyone else's experiences with Lenovo or other brands of notebooks.

[Portreve]

“Once you start down the dark path, forever will it dominate your destiny.”
— Yoda

I know that there's power management middleware on Apple's computers (SMC) but I don't know if standard x86 boxen have anything equivalent to it.

Personally, I'd do some research to find out if there's any kind of full hardware-level reset for your laptop, and if there is, try it and then go back and do a full charge of your battery, followed by a deliberate running-down of that charge, and repeating the charge/discharge cycle a few times to see if perhaps some calibration was needed.

[rossdv8]

Interesting thought about a hardware reset. These Yodas are a bit of a pain to disassemble due to the 360 degree flip lid thing, so I hadn't considered looking for a way to completely reset the board. We used to have a jumper in the olden days to discharge cmos, and therefore BIOS. I'm not sure if that's what you mean. And I'm not sure if I could recover it if something went wrong. My days of working for IBM are long past, so no help there.

The battery however, is new. I have tracked the power usage on the old battery and on this new one (probably half a year old). This one was great until this last few weeks. I can't think of anything that has been done differently last month. I'll double check my usage diary though - Justin Case. Each session I log the start and end Battery state and Time used to shutdown.