Battery, CPU temperature

redj12 · 2014-07-13 12:04:24

Hi there.

I already asked this question on some french ubuntu and debian forum but never found the answers for this weird issue.

Somme details:
I bought my PC (signature) last year with W8 and there was no issues with this OS. After some days, I switched on Ubuntu then Debian. These distros were a little bit heavy for this kind of PC - intel celeron . Now I am on Arch and the problem is the same : When my laptop is on charge the maximal CPU temperature turn between 40 and 45°C. However, if I disconnect the charger, the temperature pass to 60°C with the same software opened. I can't understand this difference. Maybe 60°C is not very high but I appreciate a "cold" PC.

On ubuntu french forum some people suggest me to check if there is some difference with delivery voltage by the battery and the charger. The result :

On charge:

[*]red@Arch:~$ upower -i /org/freedesktop/UPower/devices/battery_BAT0
  native-path:          BAT0
  vendor:               TKBSS
  model:                G71C000FS110
  power supply:         yes
  updated:              dim. 13 juil. 2014 13:59:39 CEST (15 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               charging
    energy:              37,378 Wh
    energy-empty:        0 Wh
    energy-full:         47,08 Wh
    energy-full-design:  49,5 Wh
    energy-rate:         33,275 W
    voltage:             12,055 V
    time to full:        17,5 minutes
    percentage:          78%
    capacity:            94,9111%
    technology:          lithium-ion[/*]

Battery:

red@red:~$ upower -i /org/freedesktop/UPower/devices/battery_BAT0
  native-path:          BAT0
  vendor:               TKBSS
  model:                G71C000FS110
  power supply:         yes
  updated:              dim. 13 juil. 2014 13:59:30 CEST (15 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               discharging
    energy:              37,4 Wh
    energy-empty:        0 Wh
    energy-full:         47,08 Wh
    energy-full-design:  49,5 Wh
    energy-rate:         11,319 W
    voltage:             11,634 V
    time to empty:       3,3 hours
    percentage:          78%
    capacity:            94,9111%
    technology:          lithium-ion

In my opinion there is no significant difference and even if the problem is caused by this difference, I have no idea how I can influence this voltage.
I can't hear any speed fan difference and I can't see it with lm-sensors because there is no required equipment.

Any idea ?

Thank you !

Last edited by redj12 (2014-07-13 12:10:24)

zezadas · 2014-07-14 12:15:47

maybe it has something to do with cpu governor.
try to see what governor you running before and after removing battery.
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

redj12 · 2014-07-14 13:34:04

zezadas wrote:

maybe it has something to do with cpu governor.
try to see what governor you running before and after removing battery.
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

The governor is the same : powersave. There are two available governors : performance and powersave but I can activate the performance governor to see it will be some difference.
Already tried by editing the scaling-overnor file and with this command : cpupower frequency-se-g performance.

dice · 2014-07-14 14:54:14

Does your CPU usage change when switching between battery and ac?
What kind of graphic hardware do you have? Maybe this one is getting hot

Is there anything that might be related in the logs? e.g. some acpi related stuff

any difference when using ac plug without battery?

ugjka · 2014-07-14 15:03:47

I had a laptop that would switch to passive cooling (fans only on when it gets extremely hot) to save some power when on battery.
Do your fans turn off when on batterry?

ewaller · 2014-07-14 17:04:15

ugjka wrote:

I had a laptop that would switch to passive cooling (fans only on when it gets extremely hot) to save some power when on battery.
Do your fans turn off when on batterry?

Good Call. Fans do consume a significant amount of energy. It would be a very reasonable thing to allow the die temperature to climb a bit higher when energy supply is limited.

clfarron4 · 2014-07-14 17:24:32

ewaller wrote:

ugjka wrote:
I had a laptop that would switch to passive cooling (fans only on when it gets extremely hot) to save some power when on battery.
Do your fans turn off when on batterry?
Good Call. Fans do consume a significant amount of energy. It would be a very reasonable thing to allow the die temperature to climb a bit higher when energy supply is limited.

With my previous personal laptop, the temperature threshold before the fans would spin up was a good 10°C higher than on AC power in both Windows and Linux despite using the same power profiles configured to be exactly the same.

I'm not so sure with my current laptops with Linux because I haven't touched the power settings yet (stock seems good, so I've just left it).

redj12 · 2014-07-15 11:16:18

There is an integrated intel graphics card on my PC. Actually, I am sure that is a fan "issue" because when I connect the charger I can hear that the speed fan increase immediately. So if the battery life is better on Arch than W, it's probably because of speed fan ?

I guess there is no way to influence the behavior of the fan. I am right ?

Arch Linux

#1 2014-07-13 12:04:24

Battery, CPU temperature

#2 2014-07-14 12:15:47

Re: Battery, CPU temperature

#3 2014-07-14 13:34:04

Re: Battery, CPU temperature

#4 2014-07-14 14:54:14

Re: Battery, CPU temperature

#5 2014-07-14 15:03:47

Re: Battery, CPU temperature

#6 2014-07-14 17:04:15

Re: Battery, CPU temperature

#7 2014-07-14 17:24:32

Re: Battery, CPU temperature

#8 2014-07-15 11:16:18

Re: Battery, CPU temperature

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