[ltp] Running with line power and no battery

[Brad Langhorst]

On Sun, 2008-03-02 at 10:46 -0500, David A. Desrosiers wrote:
> On Sun, 2008-03-02 at 12:23 -0300, Henrique de Moraes Holschuh wrote:
> > Whomever recommended you to use the full-drain tool on Li-ION or LiPol
> > for anything else than a gauge reset doesn't know what he is talking
> > about, so just ignore any battery advice you ever got from this
> > person.
> 
> Funny too, that the tool detects that the battery is a Li-ion, and
> happily continues onward, allowing you to "exercise" it in this
> fashion. 
> 
> I can tell you from personal experience using this tool for the past few
> years across 3-4 different Thinkpad models, that it DOES give me extra
> life out of my previously thought "dead" batteries. All of them have
> been using Li-ion batteries.

Did you miss my statement AND henrique's "anything else than" clause.
Of course it gives you access to battery capacity that was previously
hidden. That's its purpose. You also destroy some battery capacity when
you run it.  The trick is knowing the trade off.

> 
> The tool will refuse to run on laptop models that it wasn't designed to
> run on. I'd like to believe that IBM would have incorporated some logic
> to detect the presence of Li-ion cells vs. NiMH cells and refuse to run
> if it were really a problem of damaging the battery itself.

Just because a tool is not good to use in all circumstances doesn't mean
that they should not provide it.  Maybe they could make it more
sophisticated to warn the user if they're running it too often.

> 
> In any case, using it on my current two 9-cell T42p batteries has given
> me about 45 minutes more life out of the batteries than before, and it
> doesn't seem to have anything to do with "calibration" that I can see,
> unless a mis-calibrated battery pack "locks" usable battery life from
> being accessible to the hardware until you recalibrate it. 

As I and others have said, it's useful in the very specific circumstance
that you need to reset the calibration of the battery.

You don't want to do it too often to avoid causing too much damage to
the battery.


brad