[the macimum]

Hi,

you know when you read the manual before you get the PowerBook, because your so excited and that is the closest way to get in touch with your powerbook, if not then forget what I just said.

My question is this: In the manual for the 12inch, it says that you should "calibrate your battery" to make it last longer and stuff. Let me know if it's worked for you, it has been going so far for me. It's not to late to do it now to improve battery life and stuff.

How to calibrate: Without turning your pbk on, charge it until the batter is completely charged, then turn it on and leave it on until the machine shuts itself down from low battery, then charge it all the way, congrats you have succesfully calibrated your pbk.

[jamil5454]

I'm not exactly sure how it works, but calibrating the battery is actually necessary for a long battery life. It's almost as if the battery "forgets" how much capacity it has if you don't calibrate it every now and then.

And another thing, don't leave your PB plugged in to the wall for extended periods of time. Unplug it and use it on its battery at least a few times a week. This will help to prolong battery life as well.

[miacomet]

I never realized that... I should real more manuals and start calibrating!

[threestain]

My TiBook battery readout is getting really really really annoying - showinh 53 mins left or something similar and then going straight to sleep no warning - help?

[phazedowt]

I could be wrong about this (and if I am, please correct me), but my understanding is that "calibrating" the battery does not affect its physical capacity at all. Instead, what it does is allow for the estimate of how much power is left in the battery to be correct. For example, if your *book shuts off when it says it has an hour left, or keeps running for an hour on 0% charge, that's an indication of having an uncalibrated battery.

[Dork.]

Originally Posted by phazedowt

I could be wrong about this (and if I am, please correct me), but my understanding is that "calibrating" the battery does not affect its physical capacity at all. Instead, what it does is allow for the estimate of how much power is left in the battery to be correct. For example, if your *book shuts off when it says it has an hour left, or keeps running for an hour on 0% charge, that's an indication of having an uncalibrated battery.

No, the issue is in the LiIon cells themselves. If they don't get periodically charged down to empty and the recharged, there's a "memory effect" where the chemical reaction gets less efficient, and it looks like the cell "forgets" how much charge it can really hold. I think that using the laptop on the battery for 5 or 10 minutes and then immediately pluggin it back in makes this memory effect worse. The best thing to do is use the laptop untethered occasionally, and make sure you run the battery down once a month or so.

As for threestain's problem, I'm afraid one of the cells in his battery pack is starting to deteriorate. I've explained my theory on this before, and if you search here, I'm sure you'll find my explanation again. (It might have been in my prior life as dreilly1.) Sorry to drop that and run, but I'm quite busy at work today....

[flanders]

I wasn't aware the the powerbook batteries had "memory" (what we used to have to put up with in NiCd batteries). If so, then the calibration is required but other than that I believe the previous poster is correct about it being the time and percentage display that needs the calibration. With that said, I always calibrate a new powerbook when I get it out of the box.

[Tesseract]

IIRC, Li-ion batteries have no (or a very insignificant) memory effect. The calibration is for the time/percentage display and the circuit that sleeps the PB when the battery is on "reserve".

[Dork.]

Originally Posted by Tesseract

IIRC, Li-ion batteries have no (or a very insignificant) memory effect. The calibration is for the time/percentage display and the circuit that sleeps the PB when the battery is on "reserve".

I'll admit that "memory" was a poor choice of words -- the problem is not the same as with NiCad batteries -- but there is a deterioration in the chemical reaction of the battery over time, and this deterioration can be lessened by cycling the battery every month.

while cycling the battery will also affect the time/percentage display, it's been my experience that it generally doesn't drift too much. If you are going to sleep when the meter says you have 50 minutes left, it's probably a problem with your battery itself, not the power circuitry.in it.

[iBorg]

Originally Posted by threestain

My TiBook battery readout is getting really really really annoying - showinh 53 mins left or something similar and then going straight to sleep no warning - help?

I have exactly the same problem with my 1 GHz Titanium PB, with either of 2 batteries. The "time remaining" readout says I have 2:30 to 3:00 at full charge, but at just under 1:00 remaining, suddenly goes to sleep, with no warning. I've tried calibrating the batteries, resetting the PMU, resetting NVRAM, zapping the PRAM, using Disk Warrior, repairing permissions, etc., etc., but the problem remains. Odd that it would affect 2 different batteries at about the same time.

I generally run on AC, except for periods of under 1:00, and I don't know when this began - I think under 10.4.2.

Anyone have any ideas? My AppleCare runs through the first week of December, so I may have to send it in ....



iBorg

[phazedowt]

this page is insightful:

http://www.batteryuniversity.com

[Charles Bouldin]

I may be wrong, but I think this means that one cell in the battery is dead/weak. I am not sure of the exact details, in terms of what is happening with the battery, but am pretty sure that the battery will need to be replaced. FWIW, Apple replaced an iBook battery for me, under warrantee, with those exact symptoms.

[Dork.]

Originally Posted by phazedowt

this page is insightful:

http://www.batteryuniversity.com

Interesting. That page (and others I've looked up since this thread started) seem to indicate that LiIon batteries din't ever need to be discharged fully, and short stints off the battery are a good thing. (i.e. charging to full, working for 15 minutes off the battery, and then re-charging back to full) Which contradicts some pages I've read when I first looked into this, which said that too many short recharges can deteriorate the battery faster, and that a full recharge every month or two would prolong the life of the battery.

[rjenkinson]

batter calibrated!

-r.

[phazedowt]

Originally Posted by Dork.

Interesting. That page (and others I've looked up since this thread started) seem to indicate that LiIon batteries din't ever need to be discharged fully, and short stints off the battery are a good thing. (i.e. charging to full, working for 15 minutes off the battery, and then re-charging back to full) Which contradicts some pages I've read when I first looked into this, which said that too many short recharges can deteriorate the battery faster, and that a full recharge every month or two would prolong the life of the battery.

Right, this is what I've been told by engineer friends of mine as well-- that Li-Ion batteries don't suffer from the memory effects that Ni-based ones do. On the downside, they have a limited life (capacity drops with use) and that the rate of that drop is simple a matter of how charged it is and ambient temperature (if its fully charged all the time, it will "age" faster). The calibration is only to calibrate the circuits that determine how much charge the computer thinks the battery has left-- not its "actual" capacity.

[phazedowt]

Originally Posted by Dork.

Interesting. That page (and others I've looked up since this thread started) seem to indicate that LiIon batteries din't ever need to be discharged fully, and short stints off the battery are a good thing. (i.e. charging to full, working for 15 minutes off the battery, and then re-charging back to full) Which contradicts some pages I've read when I first looked into this, which said that too many short recharges can deteriorate the battery faster, and that a full recharge every month or two would prolong the life of the battery.

Right, this is what I've been told by engineer friends of mine as well-- that Li-Ion batteries don't suffer from the memory effects that Ni-based ones do. On the downside, they have a limited life (capacity drops with use) and that the rate of that drop is simple a matter of how charged it is and ambient temperature (if its fully charged all the time, it will "age" faster). The calibration is only to calibrate the circuits that determine how much charge the computer thinks the battery has left-- not its "actual" capacity.