New clamshell battery dies at 30%? Should I re-calibrate?

[Littleodie914]

Hey guys, I just bought a new clamshell battery for my iBook, as the old one wouldn't hold a charge. It powers up just fine, the estimate of 2 1/2 hours sounds about right, and everything goes smooth until the battery hits the 30% mark. The computer just shuts off. Doesn't shut down, shuts OFF. Like you pulled the battery out. When I plug it into the wall immediately following the "death", it boots up and begins charging, starting at 0%. Does this mean that the battery actually is at 0% when it says 30%? So Mac OS X doesn't know to sleep? Is there a way to manually re-calibrate? I've tried letting it start at 0% and charge up to 100% while staying awake, and have let it wear down until it does, but to no avail. Any suggestions please?

 

[AdamR01]

Maybe try restting the PMU. Im not sure exactly how to do it on that model, but the apple website should say how.

 

[Mord]

my snow ibook started doing that, but i use my battery heavily, i drain it once a day every day, and twice on weekends.

 

[tamara6]

You might find this web page useful:
http://www.girr.org/random_stuff/pb15_battery_life.html
Scroll down and read the stuff under "Notes on Lithium-Ion Batteries"

 

[Littleodie914]

Oh wow... That bottom part really is helpful. Especially the two graphs, I think those pretty much explain what's going on. Because I have a "dead cell", does this mean that a re-calibration won't fix the sudden death? (Thanks for the help so far guys! )

 

[lazymuoio]

i would recalibrate and if it continues to die at 30% then you defintley have a dead cell and should replace the battery best of luck with the situaiton

 

[tamara6]

There is another web page somewhere, but I just can't find the link to it, that suggests that continued recalibration when your battery has a dead cell can actually be harmful to the battery.

My Pismo battery was in this sort of shape last year, and I didn't realize what was going on. I tried recalibrating, resetting anything that could be reset, etc. and nothing helped - in fact, battery life only got worse. So my advice is don't let your battery run down completely - that seems to be really bad for it at this point. If you know your battery dies when it says 30%, then plug it in at 50% and recharge it.