[geeks] Extending laptop battery life

[velociraptor]

When I owned a cell phone store a while back, one of my customers was
a battery engineer from Lawrence Livermore Labs, and this info is from
him.

On 5/10/07, Jonathan Groll <lists at groll.co.za> wrote:

> Modern laptops now are Lithium-Ion type, so we shouldn't have to
> completely drain and recharge our batteries? Right? How well do laptop
> batteries deep cycle actually? Is there any benefit to removing your
> laptop battery until you actually need it (where that can be done).

"Deep discharge" is bad for L-Ion batteries.  After the first couple
of 100% charges, the battery life of these batteries is best preserved
by keeping the battery between 40 & 80% charged.

You are correct in assuming it's best to keep the battery out of the
laptop when the computer is on mains, if it is possible to do so.  For
longest life, put your Lithium Ion battery (after charging to 80% or
higher) in the fridge or freezer--they hold their charge longer that
way.

Leaving them in when the computer is on A/C means the battery is
constantly topped up (in most cases), and that the battery is exposed
to the heat of the computer.  Heat is a Lithium Ion battery killer,
because it causes the crystallization of the battery to happen faster.
 So don't leave your batteries in your car during the summer, either.

> Apple's recent release of a firmware fix (1) to correct battery problems
> has made me wonder if intelligent software cannot help us to extend
> battery life, by for example performing controlled charge and discharges
> while you work.  Surely someone has done this, if it would work? I'm not
> talking about the traditional battery calibration that most laptop
> manufacturers recommend.

Apple has also managed to kill batteries via this same method [0].  I
would wait for a few weeks and monitor the Mac forums before applying
this update to my MacBook, just to see if there's any negative
fall-out.  The rush to release sometimes, and QA suffers for it, as is
to be expected.

I suppose that you could tweak the firmware of the battery somewhat,
but as stated above, doing "memory erasing" discharges on Lithium-Ion
batteries (nor NiMH batteries) is not necessary, and in fact harmful
for Lithiums.  Lithiums have a hard life limit, every charge/discharge
causes crystallization that shortens the life of the cells.

NiMH are different, in the more that you use them during their early
life, the better they work.  The good NiMH chargers actually
"exercise" the batteries to improve their performance, so that they
have a longer life, even if you aren't using them regularly.

=Nadine=

[0] 10.2.6 killed a bunch of batteries.  Apple ack'd the damage to
iBook batteries and replaced them for ppl who had the problem.  But
they never ack'd that the change also broke Pismo (earlier G3 sold
with OS 9) batteries.  I had a battery that would run 3+ hours in
power conservation mode go to <20 min after the update. :-(  I now do
all OS updates on mains with no battery or external firewire drives
connected (not just off--disconnected, same for desktop).