[new_apple]

Some of you might have seen my post at Macrumors, but I thought this might be interesting in it's own right. I have an 18 months old iBook (1GHz, 768MB RAM, Tiger 10.4.3). My usage pattern can be summed up as: Thou shall not use your iBook plugged in. This means that I use it almost exclusively running on battery, even if I'm at home. When I'm done using it - I charge it. When I bought my iBook I decided that I wouldn't get "anal" about charging the battery: Meaning I wouldn't worry about calibrating, sensible charging, etc.

Well, yesterday I started noticing some irratic behavior. When my battery reaches 50%, the iBook turns off (off as in "off", not "sleep"). If I turn the iBook around and press the battery indicator it doesn't light up at all, indicating that the battery is flat. I can not start the iBook again untill I've plugged it in. But, after I've done that, the battery indicator will happily give me 2-3 green lights. I've checked a squillion different battery programs and they all show the same: The battery is at 50%. OK, let's see. I unplug it, and within two minutes it will die.

I have resetted PMU and all the other stuff (PRAM, I think?), also ran a hardware test and it came out fine.

Question #1: Is it likely that my battery is dead?

Another thing, I downloaded CoconutBattery and it gives me this information:


742 cycles, 18 months old, and still providing 81% of the original 4400 mAh! Now, I know that this post started with a problem, but up until yesterday I've enjoyed a solid 4hrs of battery time on a full charge. I have to say that I'm impressed, at least with my dumb-ass charging policy. I mean, a reduction of 1.1mAh per cycle. Man!

[mduell]

Shutting off at 50% is a usually a good indication that you need to calibrate your battery. (Here are the directions for calibrating an iBook battery.) However your usage pattern makes it sound like every cycle is a calibration cycle.
I'd guess the capacity that it's telling you is a fanciful lie, and that's why it's shutting down when it claims 50% remaining.

[frdmfghtr]

Agreed that a calibration is in order, but the usage doesn't look like every use is a calibration cycle...if the iBook is put back on the charger before it shuts itself down, then it's not a calibration cycle. Likewise it has to go to a full charge before the capacity is recalculated.

Now, I'm not terribly experienced with my own iBook, so this reasoning could be completely out the window. I'd venture that the iBook shut down completely due to a flat battery, but indicated 50% capacity left right before due to a terribly out of date calibration. Now, that it was drained flat and fully recharged, it was able to calculate the new actual capacity.

The question that comes to mind is: was this the first time it ever shut itself down? It could be that this was the first time you "ran the distance" so to speak on the battery so in essence you inadvertantly did a calibration cycle.

I will say that 740+ cycles and only losing 20% of battery capacity is darned good, if it is in fact true. The 4400 mAh battery pack on my HP is down to 2200 mAh after only about 120 cycles. Could be different battery chemistry or that it gets hotter in use (higher current draw than the iBook) therefore aging it faster. Speculation on my part as I'm no battery expert, but I did read that heat degrades battery capacity, and the battery always got pretty warm when in use.

Run a full, proper calibration cycle and let us know what you get, I'm very curious to know what is possible out of a newer iBook

[new_apple]

Unfortuantely there is no way I will be going through a full calibration cycle. It dies every couple of mAh's, so going from 1800mAh to 0mAh would take forever

But I can vouch for the battery, going through 18 months have certainly put a toll on it. I guess I'll just pick up a new one and see if it's as good as this one. Seriosly doubt it, though...

[mduell]

Originally Posted by new_apple

Unfortuantely there is no way I will be going through a full calibration cycle. It dies every couple of mAh's, so going from 1800mAh to 0mAh would take forever

What I'm saying is that the 1800mAh claim is probably bogus, and in reality much closer to 0. Do your best to drain it.
If you have a multimeter handy, drain the battery like Apple says and then check the voltage; if it's only a couple volts then the battery should be effectively empty.

[Kelvin]

Wow, 742 cycles and still over 80% capacity. My 14" 1.2ghz iBook battery only has 51 cycles in 17 months and it is at 72% according to Capacity Meter. I've recalibrated it several times.

I'd venture to say that if you let it run down to where it goes to sleep and the charge it without using it and it still exhibits the same behavior it's time to get a new battery. Newer Tech has some high capacity batteries.

Kelvin