12.04 draining battery on ThinkPad T420

[lads]

Ok, after week with long battery life it is now back to 2 hours. Conscientiously I haven't made any changes to the set up, although every day day dozens of new packages are being upgraded.

I checked the TLP config file and it remains enabled. Also confirmed that /etc/rc.local is void. Any clued on why TLP may have stopped functioning?

Thank you.

[lads]

I was away for a week. When I come back the upgrade installed 93 new packages and now the battery can last almost 6 hours. This is great, back to the levels of 11.04.

[ultimatebuster]

I don't know if it is my battery weakening or the days are hot.. but I'm barely getting 2 hours now (used to be about 4, I keep my max charge at 80%)

Currently using about 16.7 W of power. I only have chrome and a couple of terminal out. The air temperature is around 27C and CPU is at 62C, fans are at 3300RPM.

I know the days are hot, but I used to be able to run my system at around 45C with 0RPM (really something like 900, but reporting is weird) at around ~10W

Ideas?

[lads]

I only have chrome and a couple of terminal out.

Hi ultimatebuster, here's a bit of my experience.

I spent the last week at a conference where I was able to use this laptop throughout the whole day without recharging. With both the graphical and wireless cards switch off the battery should last 8 hours doing simple things like reading or taking notes. Switching on the wireless card for some internet navigation reduces this time to about 6 hours, if you don't access pages with much flash.

But whenever I started Chrome all of this changed, the fan with go close to max and after a few minutes I'd start feeling the warmth on my skin. Basically Chrome is a CPU hog and can't possibly be used if you want the battery to last. Throughout the conference I only used Firefox, thus keeping the impact on battery time limited.

Hope it helps.

[ultimatebuster]

Hi ultimatebuster, here's a bit of my experience.

I spent the last week at a conference where I was able to use this laptop throughout the whole day without recharging. With both the graphical and wireless cards switch off the battery should last 8 hours doing simple things like reading or taking notes. Switching on the wireless card for some internet navigation reduces this time to about 6 hours, if you don't access pages with much flash.

But whenever I started Chrome all of this changed, the fan with go close to max and after a few minutes I'd start feeling the warmth on my skin. Basically Chrome is a CPU hog and can't possibly be used if you want the battery to last. Throughout the conference I only used Firefox, thus keeping the impact on battery time limited.

Hope it helps.

I've heard about this. I'm going to try to switch to fx for the day and see what happens then report back.

I have graphics switched off as well though I do have bumblebee setup.

Edit: Here's powertop just with firefox open:

(at 72% battery)

Still looks pretty bad. I've checked the laptop's internals for dust and its fairly clean. The laptop is also a year old, so the battery has perhaps degraded a bit.

acpi -v output:

Battery 0: Discharging, 65%, 01:46:23 remaining
Battery 0: design capacity 5616 mAh, last full capacity 3297 mAh = 58%
Adapter 0: off-line
Thermal 0: ok, 56.0 degrees C
Thermal 0: trip point 0 switches to mode critical at temperature 98.0 degrees C
Cooling 0: LCD 3 of 15
Cooling 1: Processor 0 of 10
Cooling 2: Processor 0 of 10
Cooling 3: Processor 0 of 10
Cooling 4: Processor 0 of 10

Edit 2:
More tests later: 30 minutes drained about 30% of my battery. Just checking periodically I can see my power usage at around 15W or so. This really should be at like 11 or 12W even with just Firefox on.

However, I would say that the days are hotter, hence the fans are working harder.. (If the fans are at 1900 RPM the target power usage is reached). However, it's only 20C today compared to yesterday's 27C. So I'm not sure if this is an issue with the OS or just the room temperature at fault.

[lads]

Hi again ultimatebuster. The discharge times you are reporting are about the same I had with kernel 3.0. Are you using Ubuntu 12.04? And if yes, have you installed TLP?

Note that after installing TLP the battery usage didn't went immediately to its full potential. As I reported before, it was only after a package upgrade that it started working properly.

[ultimatebuster]

Hi again ultimatebuster. The discharge times you are reporting are about the same I had with kernel 3.0. Are you using Ubuntu 12.04? And if yes, have you installed TLP?

Note that after installing TLP the battery usage didn't went immediately to its full potential. As I reported before, it was only after a package upgrade that it started working properly.

Yes for 12.04, Yes for TLP. Yes everything is fully up to date.

My battery is degrading, I know, as made evident from acpi.

I'm currently under windows now (to test this power, I installed a bran new windows installation with all the proper drivers, including nvidia's optimus) and I'm drawing about 10 - 11W of power on average. The fans are much quieter, as well (though battery life is not good as my battery is dying, but still better than under Ubuntu)

If you want me to run any other tests to help diagnose the issue, I'll be happy to.

[lads]

Hi again ultimatebuster, I'm sorry but I can't help much more, I'm more of a user than a real Ubuntu geek.

Prior to kernel 3.2 I used the Xubuntu graphical interface whenever I needed the battery. It increased usage time by some 25%.

Best of luck.

[ultimatebuster]

Hi again ultimatebuster, I'm sorry but I can't help much more, I'm more of a user than a real Ubuntu geek.

Prior to kernel 3.2 I used the Xubuntu graphical interface whenever I needed the battery. It increased usage time by some 25%.

Best of luck.

I'm on Xubuntu as well. I'll try to see for myself is there's any tests I should run and will report back if I find anything.

[lkm32]

Hi ultimatebuster,

In my experience (ancient T400 user here ... upgrade next year), the main culprit is always the damn fan. It is pretty strong and for good reason ... it is not designed to stay always on. Install thinkfan and run it after a reboot with "sudo thinkfan". That will save a lot of power that was previously going to keep your laptop unnecessarily cool.

For me, I had to install lm-sensors and run "sudo sensors detect" for thinkfan to be accurate. However, after that I stuck with the defaults and it literally doubled my battery.

Also, thanks to this thread I will install TLP ... it sounds awesome. Currently with my aging 9-cell I get around 5 hours. I'm planning to switch from chrome and use TLP to hopefully get a few more hours.

Anyhow, good luck with that