[P1] FW: [P1] Prolonging Battery Life

BG briang113 at pacbell.net
Fri Jun 25 14:19:02 PDT 2004


I have been following this post also i am always looking for more and 
longer battery life.

Anyway on to my tale.  I bought an ibook 500 dual USB back in Aug or 
Sept  03.
When I got it the battery would only last for 30 of 40 minutes.
I tried everything I could think of to get more life out of it.(I.E. 
cycling thru discharge and charge, leaving on charge for a couple of 
days etc... tried some 3rd party battery software.....no luck.

I figured it was just used up so I bought a new battery.

I thought about rebuilding the old one with some new cells( i have done 
this with NiCads for my duos. Anyway after taking it apart and pricing 
cells decided not to, too expensive and complex.
Put the battery in my desk and forgot about it (meant to recycle it one 
of these days).

So this post got me thinking about it. Pulled it out today and it was 
dead. so I put in my iBook and let it charge. It took almost 4 hours to 
reach full charge. But according to the battery monitor i have 3 hours 
of power in this baby. I am surprised and amazed.

Anybody have any ideas as to why it is now a viable battery after 
sitting for almost 9 months?
Anyone have any thoughts or insight?

Thanks

BG








On Jun 22, 2004, at 6:08 PM, KhooCK wrote:

>
> 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
**************************
Brian G
Personal Mail
briang113 at pacbell.net



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