Power Management
brad longo
Bl0ngo067 at aim.com
Tue Feb 17 04:02:19 UTC 2009
Matthew Garrett wrote:
> On Mon, Feb 16, 2009 at 07:02:52PM -0500, brad longo wrote:
>
>> As I'm sure most of you know, leaving your laptop plugged in and
>> charging with a full battery charge is harmful for the battery. I have
>> been trying to see if Fedora's power management tool has something built
>> in so that when the battery reaches full charge, it will then discharge
>> to lets say around 95% before beginning to charge again. Friends of
>> mine with the same laptop use such measures except they are running
>> windows. However, based on the fact I did not see any documentation
>> about this, and that my battery charge does not appear to fluctuate at
>> all once it becomes fully charged (according to the statistics), I'm
>> guessing no such thing exists in Fedora. Does anyone have any
>> information as to whether this safety feature exists in Fedora, or
>> whether some other measures exist instead? Basically I'm just wondering
>> if I need to periodically unplug my laptop to preserve the lifespan of
>> the battery, which would be annoying. Also if this is not a feature is
>> anyone working on developing something like this for Fedora?
>>
>
> Charging of the battery is generally under firmware rather than software
> control. Laptops will typically stop charging at 100%, at which point
> the battery will slowly self-discharge. When the battery hits some
> threshold (typically somewhere between 95% and 97%) the firmware will
> start charging again.
>
> What you're talking about is presumably an interface to modify that
> threshold. This is device specific. The tp_smapi driver (which is not in
> the kernel for exceedingly dull reasons) allows this to be configured on
> Thinkpads. I don't believe that we know how to on any other systems.
>
>
Thanks this is the information I was looking for.
--Brad
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