Discharging Li-Ion's deeply (to zero) is not necessary and will be too much
of a cycle and you could be reverse charging a weaker cell. A slow discharge
using a resistive load such as a lamp at a current of around 5% of normal
discharge will suffice with NiCad or NiMh but not Li-Ion. It is not necessary
to cycle Li-Ion because they don't have the so-called "memory" effect.(see
links)

http://www4.tomshardware.com/mobile/01q1/010126/notebooks-08.html
http://www.batteryoutlet.com/comps.htm

Rick


Pic Dude wrote:

> Between my 2 main batteries, and 1 aux battery, I used to get over
> 8 total hours of laptop usage, but that's down to less than 1 hour
> nowadays, as the battery life is fading.  I once invested some time
> in manually fully discharging and fully recharging one battery about
> 5 times, and it pick up a lot of life, but again it's fading.  Used to do
> that with model airplane nicads, but it apparently worked for these
> Li-Ion's.
>
> Discharging involved leaving the laptop on until it warns of battery
> failure and then puts itself to sleep, then I'd re-awaken it and let
> it drain some more.  At some point, it just died.  Then I would put
> it back to charge fully.  Needless to say, I didn't like letting the OS
> die un-gracefully.
>
> There's got to be a better way -- is there some form of battery
> cycler that I can purchase or build that will work for these (IBM
> Thinkpad 600x) batteries?
>
> Cheers,
> -Neil.
>
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