Sudden decrease in battery life ?

[Troels]

Hi,

Maybe i did something stupid on my T42 - followed IBM's battery reconditioning guide. While it improved battery capacity to 42.2 Wh from roughly 39 Wh, the T42 runs for a much shorter time.

Before it was about 4 hours.... now it's below 3. Also, charging takes about two hours now... i'm almost sure charging from 30-100% was quicker before. Charging in the 85% region an upwards takes a long time, it seems to charge much quicker in the 40% range.
I'm charging right now, and it has been at 96% for the last 13 minutes!
The guide i followed was the "fully discharge battery till it goes into hibernate, then insert AC adaptor".

The battery is from dec. 2004 and has had about 70 cycles, it's the 6-cell from Sanyo.

Has anyone experienced something similar with a sudden decrease in battery life ? What was the cause ? How did you "fix" the issue ?

[K. Eng]

That actually sounds about normal for a year's worth of use.

Charging in the 85% region should be slower than in the 40% region. Lithium Ion batteries charge quickly and then slow to a trickle charge in order to avoid overcharging.

Unforutnately there is not much you can do except buy a new battery. LiIons degrade over time.

http://www.batteryuniversity.com/ is a pretty good resource and better at explaining these things than I am!

[Troels]

Hi, thanks... very informative link... stumbled upon this: http://www.batteryuniversity.com/images/parttwo-34.gif, which makes me wonder if Li-ions really is the best for a laptop afterall.... i mean, doesn't look stable with temperature at all, and does not last long.

It's just amazing how "fast" that the battery lige on the t42 went down... guess i will need a new battery in mid summer or so...

[christopher_wolf]

Well, it is way better considering the alternatives;NiMH, ugh...the capacity goes down alot ( I know of several Dells that have around 15 minutes of Battery Life), then Cadmium-based..Which nobody would put in a Laptop.

Looks like the next step would either be a Hydrogen Fuel Cell, and organometallic material, or a Cold Fusion Reactor.