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My Asus Zenbook ux31e is suddenly shutting off without any warning. This happens, when it runs on battery and the CPU is under load. When I run it with the power cord connected, it runs fine. So I think, my battery might be bad and can't deliver enough power, when the CPU is under load.

I tried different operating systems (Windows 7 and Gentoo Linux). I also tried to recalibrate the battery by fully charging and discharging it several times.

I'm thinking about buying a new battery off ebay, but I wanted to hear a second opinion. I don't want to spend 60€ and then notice, that the battery wasn't the problem...

Some diagnostics:

$ acpi -V
Battery 0: Charging, 0%, 81:25:42 until charged
Battery 0: design capacity 8250 mAh, last full capacity 6840 mAh = 82%
Adapter 0: on-line
Thermal 0: ok, 42.0 degrees C
Thermal 0: trip point 0 switches to mode critical at temperature 103.0 degrees C
Thermal 0: trip point 1 switches to mode passive at temperature 105.0 degrees C
Cooling 0: x86_pkg_temp no state information available
Cooling 1: LCD 0 of 10
Cooling 2: Processor 0 of 10
Cooling 3: Processor 0 of 10
Cooling 4: Processor 0 of 10
Cooling 5: Processor 0 of 10

$ upower -i /org/freedesktop/UPower/devices/battery_BAT0
  native-path:          BAT0
  vendor:               ASUSTek
  model:                UX31-35
  power supply:         yes
  updated:              Do 16 Mär 2017 11:17:44 CET (5 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               charging
    energy:              0 Wh
    energy-empty:        0 Wh
    energy-full:         39,697 Wh
    energy-full-design:  47,88 Wh
    energy-rate:         0 W
    voltage:             5,591 V
    percentage:          0%
    capacity:            82,9094%
    technology:          lithium-ion
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  • can't say I've ever heard of a lithium battery suddenly not being able to provide enough current. Even so, I'd imagine the laptop would just under-preform, not shut down. One possibility could be that your battery is reaching a thermal limit. Do you have any way of measuring battery temp? Or even just poping it out and seeing if it's perticularly hot after the laptop shuts down
    – Blaine
    Mar 16, 2017 at 9:47
  • Shutting off might be because of tempereture. Batterie often heat up and give a significant contribution towards reaching the temperature limits. Try to keep the pc cool when running on battery and see if the issue persists.
    – simlev
    Mar 16, 2017 at 9:49
  • Could also be the laptop internal power circuitry that is not performing as expected. Take it to the laptop repair shop or repair under warranty if applicable. Don't hurry with buying a new battery as this may not solve your problem
    – Art Gertner
    Mar 16, 2017 at 9:49
  • Can you try this utility and analyse your battery? nirsoft.net/utils/battery_information_view.html Post the details of this software output in your question. You can notice the battery wear level. Which tells you whether your battery is dead or not.
    – Lucky
    Mar 16, 2017 at 9:52
  • Thanks for the comments so far. I'm currently running Linux, so I had to switch to Windows to run that software. But I can monitor the temp under linux. I'm going to write a script, which writes the temp to a file, so that I can see the last temp before it shuts down.
    – henrik
    Mar 16, 2017 at 10:15

2 Answers 2

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Looks like your battery isn't complete dead as 82% of its original capacity remaining normally means "some wear but by far not terminal yet".
Batteries gradually wear and loose capacity, taken ever shorter time to run out of juice and taking longer to charge, but that is a gradual process.
Typically you would replace the battery when its run-time before being empty becomes too short to be usable. For some people that is at about 50%, others make due until 25% remaining capacity and some people just remove the worn out battery completely (no point in wasting power keeping it charged) and run the laptop solely on mains power. It depends on your usage fo the laptop what makes sense.

But in your case thiscould mean it isn't gradual wear over the entire battery, but 1 of the cells inside the battery is completely dead, which is a different matter.
E.g with a 6 cell battery (the most common type) and 1 cell out you have 5/6 capacity remaining or 83% (write up the other 1% to some wear and internal losses).
A damaged cell typically means that more heat than normal is produced while discharging. And this in turn could cause a thermal shutdown if things overheat. Small notebooks in general aren't known for heaving very good cooling so overheating is fairly easy.

If the laptop is still under warranty have it checked.
(Please note that many vendors only give 6 months or 1 year on the battery itself even though the warranty on the laptop is longer.)

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0

I suspect your battery is bad - maybe a bad cell which is sucking power as well as what the system needs to put out. I am aware of others facing this kind of problem with dying batteries.

I think its unlikely to be an issue with temp/heat because the CPU would throttle back and things would go more slowly, not shut down.

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  • I agree this sounds like a bad cell (see my answer, you just beat me by a few seconds), but I don't agree on the heat/thermal issue. Depending on where the temp-sensors are located in the laptop it could certainly cause a thermal shutdown WITH or WITHOUT CPU throttling. I have seen enough cases (We have about 6000 laptops of various brands in our organization and we see at least 1 per month with such issues.)
    – Tonny
    Mar 16, 2017 at 10:52
  • @Tonny I defer to your more in-depth experience.
    – davidgo
    Mar 16, 2017 at 10:57
  • We saw a really bad case last year with a HP ZBook 15 laptop. It was continuously being used on heavy load and (in hindsight) 1 of the cells had already failed weeks before. User had gotten warnings about that on screen but he simple clicked them away. The extra heat eventually took down the cell next to it. Combined heat melted the plastic stickers/labels on the case and outside of the battery fusing the battery to the case. Had a hell of a time getting it out without damaging the laptop. Laptop was fine though after the battery was replaced. And it smelled really bad for weeks afterward.
    – Tonny
    Mar 16, 2017 at 12:23

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