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avieth
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Location: Canada
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 Posted: Wed Feb 17, 2010 9:55 pm Post subject: Normal Laptop Power Consumption? |
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I'm disappointed with my laptop's battery life. I can get just over 2 hours of continuous use from it. The computer and battery are less than a year old, and I've kept good care of both.
I'm wondering if ~1655 mA is a normal rate for a laptop battery while doing non-intensive tasks like word processing, browsing the web, listening to music. |
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eccerr0r
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Joined: 01 Jul 2004
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Location: almost Mile High in the USA
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| Posted: Wed Feb 17, 2010 10:23 pm Post subject: |
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Depends on the laptop (CPU? chipset? software being used?) and battery pack configuration. mA doesn't mean much, a more useful number is W (watts).
Browsing the web - involves wireless? That can go through power. Also if you're spinning up/down the disk or cdrom unnecessarily it can use power quickly. Playing mp3s can potentially use battery power more than idling...
Batteries can degrade 10-20% in a year.
Usually not much you can do about it... may want to look into powertop or something to check interrupt usage when idle....
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carcajou
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Joined: 10 Jun 2008
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| Posted: Wed Feb 17, 2010 11:13 pm Post subject: |
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Battery capacity loss is completely normal thing and I guess it depends a lot on how extensively you use your laptop on both - battery and AC power. In general, you should give us more information about your hardware and power management settings (probably the most important thing). Also, what is declared battery life for your model (technical specification by manufacturer)?
My laptop is almost year old, but it's my only machine and it's powered almost 24/7. I noticed certain battery life degradation (~ 3 h > ~ 2.20 h maximum; not idle of course, "light" work/entertainment - browsing, music, videos, office and similar). Previous one's (I sold it before purchasing this one) battery went dead 2 months after I sold it, but it was also my only machine and I used it extensively for 2 and half years (though maximum battery life when it was new ~ 2 h max).
In your case, I would focus on power management (check Gentoo docs), which is also on my todo list but I simply can't find enough free time. Powertop is excellent suggestion and also this site contains lots of useful tips http://www.lesswatts.org/index.php. |
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Jaglover
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Location: Saint Amant, Acadiana
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| Posted: Wed Feb 17, 2010 11:33 pm Post subject: |
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| Quote: | | mA doesn't mean much, a more useful number is W |
P = U x I
Where P is power in watts, U is voltage in volts and I is current in amperes.
Say, 18 V and 1.655 A will give power consumption 29.79 W. |
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avieth
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Joined: 17 Sep 2004
Posts: 1945
Location: Canada
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| Posted: Thu Feb 18, 2010 12:44 am Post subject: |
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| Jaglover wrote: | | Quote: | | mA doesn't mean much, a more useful number is W |
P = U x I
Where P is power in watts, U is voltage in volts and I is current in amperes.
Say, 18 V and 1.655 A will give power consumption 29.79 W. |
I remember this from high school physics 
My power management scheme is good, in my opinion. I have both cores of my CPU set to the 'ondemand' governor at all times. The cores are only set to full speed (2GHz) if I set it myself. Laptop-mode is enabled when AC is unplugged, and my screen dims automatically.
The laptop is a Lenovo Ideapad Y430:
Intel Pentium Dual-Core T3200
14.1" Screen
Integrated Intel graphics
Battery Info:
| Code: |
present: yes
design capacity: 5616 mAh
last full capacity: 5616 mAh
battery technology: rechargeable
design voltage: 11100 mV
design capacity warning: 420 mAh
design capacity low: 156 mAh
capacity granularity 1: 264 mAh
capacity granularity 2: 3780 mAh
model number: PABAS024
serial number: 3658Q
battery type: LION
OEM info: SONY
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carcajou
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Joined: 10 Jun 2008
Posts: 240
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| Posted: Thu Feb 18, 2010 6:13 pm Post subject: |
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| avieth wrote: |
My power management scheme is good, in my opinion. I have both cores of my CPU set to the 'ondemand' governor at all times. The cores are only set to full speed (2GHz) if I set it myself. Laptop-mode is enabled when AC is unplugged, and my screen dims automatically.
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Once again check the link I attached in my previous post and http://www.gentoo.org/doc/en/power-management-guide.xml. There are lots of useful tips which could improve your laptop's battery life. Also, laptop-mode offers lots of configuration files for "advanced" power management located in /etc/laptop-mode/conf.d, so you could check them out in case you missed them. One more thing - it would be good to perform battery calibration. I've read somewhere that some BIOSes contain this option and that some manufacturers provide software/utilities, but in my case I always had to do it manually (basically completely charge battery, then switch off AC power and let battery completely discharge). |
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Yamakuzure
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Joined: 21 Jun 2006
Posts: 2285
Location: Adendorf, Germany
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| Posted: Wed Feb 24, 2010 10:33 am Post subject: |
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and sys-power/powertop can give some good hints, too.
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