FW: [P1] Prolonging Battery Life

KhooCK filhos at hotmail.com
Tue Jun 22 18:08:00 PDT 2004


Hi everyone

I have been reading this thread with lots of interest. It seems to go
against my experience and understanding of lithium ion batteries. I have
always kept my battery in the book and kept it charged up >95% whenever I
can, and I lose about 10-15% of the capacity per year.

My understanding is that (contrary to what's been discussed) to maintain a
lithium battery in maximum longevity, you should charge frequently, and keep
it topped up. Overcharging does kill the battery but this is not a problem
with modern 'books because of their more sophisticated charging circuits.
Deep discharges cause more damage to capacity than small discharges.
Wikipedia has a succinct article on batteries

http://en.wikipedia.org/wiki/LiIon

 as does battery university

http://www.batteryuniversity.com/parttwo-34.htm

In summary
A) Every lithium battery degrades over time
B) Temperature is by far and away the largest cause accelerating this
degradation
C) If you are going to store a battery, take it down to 40% and pop it in
the fridge (NB one of the problems is how you keep this maintained at 40% as
the battery will lose charge continually); Apple actually recommends you
fully charge the batteries then pop it in a cool place
(http://docs.info.apple.com/article.html?artnum=10571)
D) Recalibration of the battery should be done periodically by using the
book until it goes to sleep, then recharge fully
(http://docs.info.apple.com/article.html?artnum=86284)
E) Frequent small recharging is less harmful than large recharges

Rgds
Khoo

Steve Jobs on Bill Gates:  "I wish him the best, I really do. I just think
he and Microsoft are a bit narrow. He'd be a broader guy if he had dropped
acid once or gone off to an ashram when he was younger"
(From a 1997 New York Times interview)




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