> it was fine two days ago.. then.. started using it.. got down to 30%
> and tried to recharge.. overnight.. still 30%.. couldn't believe it.
>
> so i thought i should drain it fully.. hard reset device and told it
> to ALWAYS stay on (using FPSUtil).. got it down to register 0% in
> FPSUtil.. charged it.. max charge = 3%.. turn on device.. even with
> device in cradle.. death..
There is a popular legend that fully draining batteries is a good
maintenance procedure. In general, this is *NOT* true, and is, in fact, a
fantastic way to speed them to their deaths.
More information, for the curious: Some types of cells, NiCds being a good
example, can benefit from being competely discharged under some
circumstances. The catch here is that we're talking about individual
_cells_, and not batteries (comprised of two or more cells). Draining the
entire battery ensures that some cells will reach 0V before others (because
no two cells are ever a perfect match). The weaker cells will then receive
a negative charge as the stronger cells drain to 0V, and this negative
charge will ruin cells quickly and effectively.
For almost all kinds of batteries, the best way to keep them healthy is by
never discharging them more than necessary (this prevents the weaker cells
in the pack from ever seeing negative voltage) and always keeping the
charge topped off when possible. In a perfect world, "smart" chargers
switch to a trickle or "float" charge once a battery is charged, to keep
them topped off. In reality, many chargers just apply a constant current
or voltage, and keep pumping current into the battery beyond 100%
capacity. This end up heating the battery and eventually shortening its
life. I have no experience with the Palm V system, so I can't comment on
how it works.
And just to preempt the inevitable comment about so-called "charge memory",
there really is no such thing in any sort of practical consumer
application. This "memory" phenomenon was documented by NASA in satellite
systems only when batteries were repeatedly discharged to the _exact_ same
level. Varying the charge level even slightly restores battery capacity to
nominal levels within a few charge cycles.
> > There is a way to bring back NiCad and Ni-MH batteries with a large
> > capacitor but I don't know if it will work with Li-ion (and I'm not willing
> > to try on my Vx just yet ).
This is *NOT* something you want to do with Lithium-ion cells. This
procedure is used to "zap" dendritic buildups inside the cell. It works in
some cases on NiCd cells, but should never be performed on multi-cell
batteries of any kind.
oge
-----
Owen G. Emry
[EMAIL PROTECTED]
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