[mdlug] OT: Replacement battery for Dell Laptop

[R. Kannan]

Dr. Meier,

Thanks for the tips. 

BTW, you have wrongly attributed my post to Dan.

Raj K

-----Original Message-----
>From: Robert Meier <list1c30fe42 at bellsouth.net>
>Sent: Apr 16, 2008 7:03 PM
>To: mdlug at mdlug.org
>Subject: Re: [mdlug] OT: Replacement battery for Dell Laptop
>
>Dan,
>
>> Another thing I read was that the battery cells themselves are fine
>> but the electronic circuit ('computer') in the pack
>> somehow detects some issues with the cells and
>> [needs] to be disconnected (to power off and reboot) to erase the memory.
>> Apparently, one of the ways this is achieved is by 'freezing'.
>
>See http://west-wind.com/weblog/posts/365.aspx for details.
>
><AFAIK>
>The fundamental problem is a power pack chip (TI???) that was programmed
>by Dell with a cycle countdown counter and a rule to disconnect the
>cells from either charging or delivering power when the counter reached
>zero.
>Each time the battery was disconnected from charging,
>the chip would increase by ~2%,
>the error with which it reported the battery charge to the bios
>erroneously low.
>
>A class action suit was being assembled, when Dell decided to
>  recall (for free replacement) its batteries
>    in laptops owned by corporations or their employees.
>    (check with a corporate-employer)
>  provide a bios patch to its computers more recent than ~C600
>    that would reset the power pack chip
>    http://support.ap.dell.com/support/index.aspx?c=au&cs=audhs1&l=en&s=dhs
>
>Any chemical battery loses energy when its temperature is cycled.
>Though disconnected from charging or delivering power,
>the batteries still deliver power to the chip which will not reset
>its disconnection.
>The goal is to discharge the batteries so that they no longer power
>the chip, at which point the disconnection rule is no longer asserted
>and the cells can be recharged.
>
>To discharge my power cell, I carefully wrapped my power cell in paper
>and a ziplock bag, and by limiting its time in the freezer, I cycled
>the temperature from 80deg F to 32deg F.  I believed the risk of
>catastrophic rupture to be warranted within this range.  The procedure
>worked unreliably, and certainly reduced the actual lifetime of the
>cells.
>
>I have since found that I can avoid the problem by periodically
>letting the batteries discharge until the computer will no longer
>attempt to boot.  By holding the Fn-F3 key, I force the bios to
>keep the screen drawing power from the battery.  I believe this
>is less damaging to the cells.
></AFAIK>
>
>Good luck,
>-- 
>Bob
>
>  "The future ain't what it used to be."
>     -- Yogi Berra
>
>_______________________________________________
>mdlug mailing list
>mdlug at mdlug.org
>http://mdlug.org/mailman/listinfo/mdlug


________________________________________
PeoplePC Online
A better way to Internet
http://www.peoplepc.com