[Ti] Battery Question

[Dennis Fazio]

--On Wednesday, March 12, 2003 03:31 PM -0800 "Chris/Gail Ladd" <ladd at citytel.net> wrote:

> Just got a new 1Gh TiBook.  Can i leave my battery installed  and then run the  TiBook  " plugged in"  (that's what i've been doing) or should I remove the battery once it is fully charged.

This is one of the age old questions that comes up frequently and solicits a lot of anecdotal advice or what some might call folk tales. Some research on the Internet will get you more expert and complete information though it may be laden in graphs, charts and chemistry beyond most of our remembrance from high school class. You can also go by a pretty decent book, written in lay terms, with a chapter on Lithium Ion batteries online at <http://www.buchmann.ca/Chap10-page6.asp>

To answer the question, then, it depends upon what you want to accomplish. For absolute, top-of-the-line, stretch-it-as-far-as-you-can, maximum battery life, you should remove it and store it in a cool place while the PowerBook is plugged in.

But....
You should not store it at 100% charge, but at 40% charge. To do that, you then have to run it down from 100% to 40% each time before storage, which creates more heavy discharge/charge cycles which shortens battery life.

Or you have to never charge it above 40% and run it from 40% to 0% while on battery, which runs it into deep discharge more frequently, which shortens battery life.

So, the easiest thing, and probably the one that gets you the overall longest life for any battery that you intend to actually use and not just display on the shelf, is to just store it at 100% charge. If you do that, you might as well just leave it in the PowerBook all the time. I have never seen any information that says Li-Ion batteries degrade faster when trickle-charged at 100% constantly vs. being stored at 100% for long periods. Anyone who has hard evidence to the contrary, please chime in.

--
Dennis Fazio
dfz at mac.com