You are not logged in.

#1 2023-01-22 23:05:35

Soptik
Member
Registered: 2019-03-11
Posts: 64

System becomes extremely sluggish when low battery and plugged in

My laptop (running X, i3, intel + nvidia) runs completely fine when not plugged in, regardless of battery level, with the same performance.

When I plug in a charger, and battery level is sufficiently low, the laptop becomes extremely slow. Very annoying and quite difficult to work with.

I have no measurements, but it feels much worse when battery is low (~ 10%), and the effect seems to get better when the battery is charged enough. At around 60% or so, the effect disappears again.

The slowness feeled to be equivalent to limiting max cpu frequency to a very low value - long delays when clicking, scrolling, writing text, etc. But when I used `cpupower frequency-info`, the output was the same regardless of whether I had my charger plugged in or not.

  hardware limits: 400 MHz - 3.40 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 400 MHz and 3.40 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: Unable to call hardware
  current CPU frequency: 400 MHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes

I thought of the powersave governor (as the slowness effect seemed to be smaller when my battery was charged more) might be to blame, but I have no idea how to debug that.

I would be glad if anyone had any idea.

Thanks

Offline

#2 2023-01-23 01:48:21

jonno2002
Member
Registered: 2016-11-21
Posts: 445

Re: System becomes extremely sluggish when low battery and plugged in

how old is the laptop ?
is the battery genuine or a knock-off ?
is the power brick genuine or a knock-off ?
the battery could be on its last legs and drawing more current than the power brick can handle.
if the power brick is not the genuine one it could be insufficient to run the laptop and charge it from low battery, you can check voltage and current ratings which SHOULD be on the underside of the laptop and on the power brick, the voltage should match and the current (A) should be the same or higher than whats written on the laptop.

i would try a different power brick first and then try another battery, thats all you can really do, unless there is actually a fault with the laptop.

just a funny note as im writing this i just checked the laptop im using and the power brick is 2.31A and the laptop requires 3.33A, i havent had any issues with it so far and the power brick appears to be genuine, i guess thats what you have to expect when you buy second hand goods, that someone has just grabbed a random part that fits and works but may not be up to standard, i will definatly look into a better power brick now that ive seen that.

EDIT: my laptop came with a docking station too which has its own power brick, both of those items have 3.33A written on them so im guessing the numbers on the base of my laptop must be for when its sitting on the docking station and requires more power headroom for all the extra usb and other ports.

Last edited by jonno2002 (2023-01-23 01:58:11)

Offline

#3 2023-01-23 13:50:46

Soptik
Member
Registered: 2019-03-11
Posts: 64

Re: System becomes extremely sluggish when low battery and plugged in

Thanks for the suggestion!

The laptop is almost four years old, the battery has not been replaced since I bought it. The power brick is genuine from Lenovo, bought about a year ago, when the original one failed. The new one actually has/supports higher voltage than the original one I got with the laptop, so I don't know whether that might cause anything?

I'll look into it a bit more.

Thanks

Offline

#4 2023-01-23 15:03:40

mukl
Member
From: Vienna, Austria
Registered: 2008-01-30
Posts: 45

Re: System becomes extremely sluggish when low battery and plugged in

My Surface Go behaves similar. I'm quite sure it's because the device gets hot when charging.

Offline

#5 2023-01-23 20:38:38

Soptik
Member
Registered: 2019-03-11
Posts: 64

Re: System becomes extremely sluggish when low battery and plugged in

That would actually makes sense! Thanks, I'll try to measure that.

Offline

Board footer

Powered by FluxBB