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Re: Battery life recovery - Everyone suggesting battery full drains, *read this*

On Thu, 2003-02-13 at 20:05, mi wrote:
> Hello Joe.
> Thanks for your enduring efforts !
> >  - Store it at 40% charge. Not 100%.
> >  - Don't leave it in the laptop while it's in mains power.
> >  - Don't store it anywhere particularly hot or cold or wet.
> Does this mean it'd be best to stop working at 40 % ?
> Never use up the battery's capability, except on emergency ?
> Wouldn't the manufactorers 'cycle span' somehow have to be seen more 
> differentiated, then ?

Really what it means is that Li-Ion batteries actually support the
typical usage patterns of laptop batteries a lot better than NiCd or

For myself I know that most use of my laptop is for long periods, so I
leave it plugged in.  If I need it on battery it's fully charged and it
actually lasts more than a couple of hours.

(A) The 40% charge thing is for _storage_ not for when you're using your
laptop (unless you only use the battery when you travel, or something
like that).

(B) Correct.  Charge your battery when you can - the deeper the
discharge cycle the worse it is for Li-Ion.

(C) I have no idea what this means.  Standards or terms invented to
describe long-term behaviour of NiCd batteries don't necessarily apply
to Li-Ion.

And, for an amusing completely off-topic side note:

In a previous career I used to be an electronics technician and one job
we had was to rejuvenate NiCd batteries for airport security radios. 
There are two failure modes for NiCd - one is charge memory, which
everyone is familiar with, and the other is that tiny threads of nickel
grow between anode and cathode, at which point you get a short circuit.

Making these batteries work again was _really_ fun.  We would charge up
a huuuugggeee bank of capacitors to 100V and ZAP!!!  Quite often this
would fuse the nickel threads inside the battery, and it would once more
take a charge :-)

Andrew @ Catalyst .Net.NZ Ltd, PO Box 11-053, Manners St,  Wellington
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