[Ham-Computers] Laptop batteries

[Hsu, Aaron (NBC Universal)]

Hi all,

There was a discussion of laptop batteries a few weeks back.  The
general rule of thumb with Lithium-ion (Li-ion) batteries is that if you
don't intend on using it, the best way to preserve it's usable life is
to store it at 40% charge in a cool, dry location.  Most all Li-ion
batteries will slowly self-destruct (due to the chemistry), but storing
at 40% charge extends the usable life of the battery over storing it at
full charge (and you never want to fully discharge a Li-ion battery).

With that in mind, those of you with Mac laptops might want to read this
article:

http://www.gearlog.com/2008/11/apple_notebooks_take_huge_perf.php

It seems Apple throttles the CPU if a battery is not installed in a
Macbook - the author of the article benchmarked a 37%(!) drop in
performance when the Macbook is run on AC-only without a battery
installed.  It's apparently a documented "feature" Apple implemented to
prevent the system from shutting down in case system power demand
exceeds what the A/C adapter alone can provide - aka, the battery is a
power buffer.  So, if you have a Mac laptop, note that it will run
slower if a battery is not installed.

My take...what a great example of poor engineering!  Don't get me wrong,
Apple laptops are nice, but I would think that any computer's power
supply should be designed to fulfill the max power demand + 20%
overhead.  Perhaps this is why the Macbooks (and the power adapters) are
so thin and light - under-powered power supply circuitry.  Granted,
Toshiba is also guilty of something similar...use an under-powered A/C
adapter and the system won't charge the battery if the laptop is powered
on.  However, there's no performance hit - just no concurrent run and
battery recharge.  Bumping the adapter to higher powered unit allows
concurrent run and charge.  BTW, Toshiba noted this in their printed
documentation.

Anyways, just my 2 cents.


73,

  - Aaron, NN6O


p.s.  Happy gobble gobble!