Is Calibrating A MacbookPro (Unibody) Battery Necessary for Battery Health?

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Level 1

10 points

Is Calibrating A MacbookPro (Unibody) Battery Necessary for Battery Health?

Hello,

For the longest time, I have been trying to figure out whether or not battery calibration is necessary for a Li-ion battery's health. I have been hearing a lot of talk about calibrating macbook batteries right out of the box and then every few months after that, so please know that *I AM TOTALLY AWARE OF THOSE OTHER POSTS AND DISCUSSIONS!* Please don't send me a link to other discussions or articles. I've heard it all. This discussion I am starting is rather unique, and has not been discussed here before, so please accept my challenge of posting new information. I have a conundrum that I hope we can work together to answer.

First off, if you read apples page on calibrating batteries ( http://support.apple.com/kb/HT1490?viewlocale=en_US) it says that calibrating the battery will help the microprocessor give an accurate estimate of how much usage time is left. However, what puzzles me is that, while most people refer to calibration as a means of maintaining a battery's health, Apple's own article says nothing about that. It merely says it helps keep it "operating at maximum efficiency." Now, my QUESTION is, is calibration necessary for a battery's health, or is it mostly meant to give the system an accurate reading of charge capacity? I know what some of you will say. Both. However, if you once again refer to Apple's article, they state that a calibration should be performed more often if you don't tend to take your laptop off of the charger.

Therefore, it ISN'T the lack of calibration that is harmful for batteries. It's the lack of use/"exercise" that harms batteries. It seems to me that battery calibration is less for the battery and more for the computer. People talk about things like the "memory effect", but this problem doesn't plague Li-ion batteries. Things have changed. Now we have microprocessors that intelligently manage the distribution of charge amongst cells. Now we no longer have to worry about uneven charge cycles because these microprocessors can break them up into different sessions.

All this to say, it seems to me that the best way to keep a battery's life long and healthy is to (a) be sure to take it off the charger from time to time, (b) not use it too frequently, and (c) be sure not to store it in improper conditions (i.e. hot/freezing car or storage with 100% charge). I truly do not see how the process of calibration is at all beneficial to the actual physical health of the battery.

One last note before you flood me with your opinions. I AM NOT SAYING THAT I THINK BATTERY CALIBRATION IS USELESS OR UNNECESSARY. I am simply curious as to whether or not it is for the computer's benefit or the battery's benefit.

Thanks, and please respond with your opinions.

Message was edited by: DirtyKetchup

Message was edited by: DirtyKetchup

Message was edited by: DirtyKetchup

Message was edited by: DirtyKetchup

MBP (mid-2009), Mac OS X (10.6.3), 500GB@7200rpm

Posted on Apr 24, 2010 11:40 PM

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Answer 1

carl wolf

Level 6

14,625 points

Apr 25, 2010 1:48 AM in response to DirtyKetchup

"For the longest time, I have been trying to figure out whether or not battery calibration is necessary for a Li-ion battery's health. I have been hearing a lot of talk...so please know that I AM TOTALLY AWARE OF THOSE OTHER POSTS AND DISCUSSIONS!"
If you are, then you know the answer. Too, there's no need for uppercase in this discussion.

"Please don't send me a link to other discussions or articles. I've heard it all."
Then, you know the answer.

"This discussion I am starting is rather unique..."
No, it is not.

"...and has not been discussed here before..."
Yes it has.

"I hope we can work together to answer."
I work alone. Calibrate your battery. It is that simple.

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Answer 2

Network 23

Level 6

12,333 points

Apr 25, 2010 2:34 AM in response to DirtyKetchup

I'm willing to accept that calibration isn't necessary for the health of the battery. I think all it does is make sure that if your battery has 6 hours on it, that it knows that so that you get all 6 hours. It can work against you too, if the meter says 6 but the true capacity is 5, calibrating should lower the estimated runtime. But this is all about the meter, not about the health.

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Answer 3

Rod Hagen

Level 7

32,000 points

Apr 25, 2010 2:50 AM in response to DirtyKetchup

The purpose of calibrating a battery is not primarily necessary to keep the lithium ion compound in the battery working properly, DirtyKetchup, but it IS necessary if you really want to get the best possible life and performance out of your battery, for quite different reasons.

If the battery isn't correctly calibrated then firstly the warnings that you receive of a low battery , and the processes that put the computer into hibernation mode may not operate at all, because the computer believes that more power is available than really is (or may conversely put it to sleep too early, leaving you with a computer battery that thinks it needs charging when it still has running power remaining. Finally, it may also cause problems for the "shut down" process in the battery itself, designed to prevent damage to the battery by overly deep discharges.

If the calibration gets too far out of whack then such problems can leave you with little alternative apart from buying a new one.

The MBP charging system is also set up to vary charge rates at different levels of charge, (including preventing it from charging at all after it has reached "100%" (as measured by the calibrated battery) and before it declines to 97% or thereabouts, with a view to maximising battery performance and physical life. If the battery is not properly calibrated then this process may not operate properly, with negative consequences for the real "health" of the battery.

So, while you are right that calibration isn't necessary to avoid memory effects with Lithium batteries (and, indeed, excessively frequent full discharges are harmful) , calibrating the battery every couple of months really is necessary if you want to get the best possible life out of the battery.

Cheers

Rod

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Answer 4

Network 23

Level 6

12,333 points

Apr 25, 2010 3:24 PM in response to Rod Hagen

Maybe the discussion goes easier if it's more granular. Not a yes/no question. Skipping calibration might shorten battery life through incorrect level readings, but maybe it's not enough to become alarmed over. For example, it is likely battery health will be impacted far more by extended high temperature operation than by someone who didn't calibrate for 6 months. Calibration may be a concern, but it might be a very, very minor concern relative to the other factors that affect battery life.

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Answer 5

Rod Hagen

Level 7

32,000 points

Apr 25, 2010 3:49 PM in response to Network 23

I agree. It is certainly not a 'Yes / No" question, Network 23. It may even depend to some extent on which model of MBP is being used.

The "new" , non-removable batteries have a much higher cycle count capability than the old ones, for example, and age is likely to weary them much faster than cycles I suspect. The trade off in cycles versus calibration etc may well be different with them from the situation with the old removable ones. The trouble is we generally only really know the answer to these things after the event with technology that is developing fairly quickly.

The removable batteries from the earlier pre-unibody MBps seem to me to have such poor longevity in most cases, and depend so much on "luck of the draw" even then, that it is hard to make definitive statements about them, but the frequency of people having trouble with premature failure and unpredictable behaviour with them makes me wonder whether regular calibration may be of some value there. It is clear that they don't like either frequent full discharges on the one hand or prolonged use as pseudo desktops without a bit of exercise on the other, though, and this, of course becomes a 'confusing variable' that makes it difficult to assess the effects of calibration alone

I've been a bit more religious about regularly calibrating the second battery in my older Santa Rosa MBP and it so far seems to be behaving better than the first one, but this may just be down to chance, of course. The non-removable battery in my newer MBP13, purchased at about the same time as the second one for the SantaRosa, is still behaving far, far better than the removable one.

But all in all plotting processes for maintaing best lithium battery life all too often strikes me as more of an art than a science still! More like alchemy or sorting out SCSI chains and termination set-ups than anything else! 😉

Cheers

Rod

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Answer 6

y_p_w

Level 6

17,642 points

Apr 25, 2010 11:41 PM in response to Rod Hagen

Rod Hagen wrote:
I agree. It is certainly not a 'Yes / No" question, Network 23. It may even depend to some extent on which model of MBP is being used.

The "new" , non-removable batteries have a much higher cycle count capability than the old ones, for example, and age is likely to weary them much faster than cycles I suspect. The trade off in cycles versus calibration etc may well be different with them from the situation with the old removable ones. The trouble is we generally only really know the answer to these things after the event with technology that is developing fairly quickly.

I would think that the technology in the new-fangled non-user-serviceable batteries might include advances in resistance to basic battery aging. Li-ion batteries have been known to lose some capacity simply as a matter of age regardless of whether or not they have been used or not.

The other thing I could imagine is that the increased published cycle count means more chances (over a longer lifespan) for the user to possibly drain it down below a damaging threshold if the battery hasn't been properly calibrated. As has been stated, the charging system is reliant on periodic snapshots to determine the current capacity and empty/full points for the battery.

I guess we could go to the old "dumb" Li-ion battery technology where there was no information storage on board the battery. That probably wouldn't require battery calibration, as the charging system would simply use instantaneous voltage/current information to estimate how much capacity is left in a battery and how to charge it. Of course I remember that those systems were known for poor overall performance and low useful battery life (100-150 total cycles was a good life for one). Then there was the matter of batteries catching on fire, swelling, or blowing up.

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Answer 7

DirtyKetchup Author

Level 1

10 points

Jul 9, 2010 7:27 AM in response to DirtyKetchup

Thanks for all the help guys. FYI, I found this great article that I think sums it all up pretty well:
http://discussions.apple.com/thread.jspa?threadID=1764220

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Answer 8

eww

Level 9

53,028 points

Jul 9, 2010 10:04 AM in response to DirtyKetchup

Yes, that's far and away the best summation of Mac notebook battery-related info in existence. It's too bad you assured us you had already read and heard everything on the subject and didn't want to hear about any links. If you hadn't said that, I might have brought neuroanatomist's excellent User Tip to your attention back in April.

Calibration doesn't benefit the battery or the computer nearly as much as it benefits the user, by insuring that s/he gets the most accurate information possible about the state of his/her battery.

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