Yes, I can confirm the same on my UX31A.
As unfortunate as the situation is it's a relief knowing that the regression is due to BIOS update. I think I'll add a warning on the UX31A wiki to warn other users of the problem. I too am hoping ASUS will rectify this error in the new year.
]]>I too can't help myself from upgrading without thought as to why I am. In my case I have been grabbing incremental beta updates from http://nbtsd.asustreiber.de/BIOS/?C=M;O=A and the charging issues were introduced between 215 and 216.
I'm considering downgrading by installing windows on a spare SSD I happen to have but haven't found the time to do so with Christmas etc. Lets hope ASUS spot the regression soon.
Richard
]]>I think this is implemented by the OEM/vendor to improve battery life, but I do not know the exact reason for this behaviour or how it works exactly.
No. Lithium Ion batteries are tricky things -- it is difficult (impossible) to determine the charge state based upon battery voltage. Most systems integrate the current (Coulombs / Second) going into or out of the battery over time in an effort to estimate the charge (in Coulombs) in the battery. These Coulomb counters are imperfect and drift over time. They occasionally need recalibration. This generally happens when a battery becomes fully discharged followed by a full recharge.
]]>It seems I've been conditioned to live the bleeding edge lifestyle. Today (for no reason other than habit), I upgraded the bios version on my UX31A from 212 to the latest 216. Now it seems my battery does not charge beyond 91%. Here is the output from some files:
cat /sys/class/power_supply/BAT0/{energy_now,energy_full,capacity}
46168000
50616000
91
Unfortunately, I don't know how to rollback my bios to 212 since the "Easy Flash" utility in the bios does not allow it. Also, I've read some posts it can be done in windows by invoking "WinFlash.exe /nodate". Unfortunately I don't have windows installed and I heard the procedure is tricky. Also, I know there is an arch wiki on bios flashing but I am afraid of bricking the board as there are no guarantees that the methods described have been tested on my machine.
If someone can shed some light on this I'd greatly appreciate it.
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