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#279731 - 18/04/2006 09:21 Laptop battery life?
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5682
Loc: London, UK
When I stopped to use the wireless in Munich airport last week, it seemed that the battery in my laptop drained itself really quickly.

I've just done a quick bit of testing today, and in 4 minutes of wall time, the battery meter reckons there are 11 fewer minutes of battery remaining.

This is on my Sony Vaio SRX87, running Ubuntu 5.10. Frequency scaling (SpeedStep) appears to be working correctly.

Is it just because the battery's getting old? I picked up the laptop in September 2002, so it's almost 4 years old. Do I need to buy a new battery, or can I recondition this one somehow?

(It also reckons that it'll take over an hour to recharge those 11 minutes of battery, but that could be a bug in Ubuntu -- I saw it claiming a couple of thousand hours to recharge the battery a week or so ago).
_________________________
-- roger

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#279732 - 18/04/2006 09:43 Re: Laptop battery life? [Re: Roger]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14484
Loc: Canada
Quote:
This is on my Sony Vaio SRX87, running Ubuntu 5.10. Frequency scaling (SpeedStep) appears to be working correctly.

Is it just because the battery's getting old? I picked up the laptop in September 2002, so it's almost 4 years old. Do I need to buy a new battery, or can I recondition this one somehow?


Time for a new battery.

Also ensure that Ubuntu is set for the "on demand" CPU governor ("Performance Profile") (if available) in both battery and AC powered modes (right click on the power/battery icon).

Quote:
(It also reckons that it'll take over an hour to recharge those 11 minutes of battery, but that could be a bug in Ubuntu -- I saw it claiming a couple of thousand hours to recharge the battery a week or so ago).

That info comes from the battery itself, so it's probably not far off. Time for a replacement battery, methinks.

Cheers

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#279733 - 18/04/2006 11:27 Re: Laptop battery life? [Re: mlord]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5682
Loc: London, UK
Quote:
Time for a new battery.


OK. I'll look into that. Thanks.

Quote:
Also ensure that Ubuntu is set for the "on demand" CPU governor ("Performance Profile") (if available) in both battery and AC powered modes (right click on the power/battery icon).


It's set to "userspace" right now. It seems that "userspace" and "ondemand" both do frequency scaling. Is there something else different that I'm missing?
_________________________
-- roger

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#279734 - 18/04/2006 11:34 Re: Laptop battery life? [Re: Roger]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5682
Loc: London, UK
Quote:
It's set to "userspace" right now. It seems that "userspace" and "ondemand" both do frequency scaling. Is there something else different that I'm missing?


OK. I found some stuff, and as far as I can tell, they're equivalent in terms of throttling, except that "userspace" requires a user-space daemon. Since this is Ubuntu, I've already got "powernowd" running.

Is there any compelling reason to change to "ondemand"?
_________________________
-- roger

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#279735 - 18/04/2006 11:53 Re: Laptop battery life? [Re: Roger]
sein
old hand

Registered: 07/01/2005
Posts: 893
Loc: Sector ZZ9pZa
Quote:
This is on my Sony Vaio SRX87


I had a Vaio 505E and a R600MX, the R600 was around a similar vintage to your SRX I'm guessing. The 505 was running Windows and Debian, the R600 Gentoo.

On both of them the out-of-box battery life was unremarkable, borderline bad. Worse than average.

After a year, they both went from just-usable to pathetic. The 505 would not manage half an hour on the original battery, and the R600 would just about make it to 45 minutes. This is on a 12-18 month old laptop.

My experience is that these slim Vaios suck. My sisters old Dell, dads Thinkpad, and my Powerbook (all about 3yrs old) last ~ 2-2.5hrs on a charge.
_________________________
Hussein

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#279736 - 18/04/2006 12:32 Re: Laptop battery life? [Re: sein]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5682
Loc: London, UK
Quote:
My experience is that these slim Vaios suck.


Except for the fact that they are slim. I don't want to lug around a heavyweight desktop replacement computer, so it's something I've been putting up with.
_________________________
-- roger

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#279737 - 18/04/2006 19:47 Re: Laptop battery life? [Re: Roger]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14484
Loc: Canada
Quote:
Is there any compelling reason to change to "ondemand"?


It outperforms the alternatives, and doesn't tie up memory for an extra process like powernowd does. That's all. If you're happy with powernowd, then no problem.

Cheers

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