Macbook battery calibration

[andriella]

The last few times I have calibrated, the capacity of my battery has decreased. With my last three calibrations, my battery has decreased from 94% to 87% of original capacity. I thought that I might have been doing something wrong, but I have checked several times that I followed Apple's instructions to the letter.

According to CoconutBattery, I have gone through 45 load cycles, and my current capacity is 4568 mAh out of the original 5200 mAh.

I have heard that CoconutBattery is sometimes inaccurate, so here is my battery info from System Profiler:
Full Charge Capacity (mAh): 4568
Remaining Capacity (mAh): 4090 (not fully charged at the moment)
Amperage (mA): 655
Voltage (mV): 12415
Cycle Count: 45

I take my Macbook to class with me daily so I need the battery to last for as long as possible.

Any suggestions?

 

[hopejr]

Which MacBook do you have (CD or C2D)? In the manual for mine, it says nothing about callibrating the battery, and when I searched on the net it said it isn't necessary (mine is a C2D). I have run down my battery completely once. The capacity at that stage was 91%, but since then it's back up to 100% according to Coconut Battery.
AFAIK, callibration does more harm than good on the new batteries that the MacBooks use.

 

[lamina]

My first word of advice would be to delete Coconutbattery. You will drive yourself nuts. I was the same way.

Do you notice your battery life dwindling? How long have you had your MacBook?

Also note that fully discharging and fully charging your battery (commonly known as calibrating) is in fact very bad for your battery from my experience, and will shorten its life.

 

[WildCowboy]

Which MacBook do you have (CD or C2D)? In the manual for mine, it says nothing about callibrating the battery, and when I searched on the net it said it isn't necessary (mine is a C2D). I have run down my battery completely once. The capacity at that stage was 91%, but since then it's back up to 100% according to Coconut Battery.
AFAIK, callibration does more harm than good on the new batteries that the MacBooks use.

I'm shocked that your manual doesn't contain any reference to battery calibration. I'm not an MBP owner, but the online manual (at least the US version) contains a large item on it in the Getting Started section. I've never seen anything about C2D machines not needing calibration, so if you have a link, I'd love to read up on it.

Also note that fully discharging and fully charging your battery (commonly known as calibrating) is in fact very bad for your battery from my experience, and will shorten its life.

I don't buy this at all...there's a reason that periodic calibration is a standard recommendation in the lithium-ion battery industry. Some people calibrate their battery and find that they have a lower capacity than they did before the calibration, which leads them to believe that calibration is hurting their battery. It's not...what it is doing is ensuring that the computer has an accurate measure of the battery's real capacity.

 

[lamina]

I don't buy this at all...there's a reason that periodic calibration is a standard recommendation in the lithium-ion battery industry. Some people calibrate their battery and find that they have a lower capacity than they did before the calibration, which leads them to believe that calibration is hurting their battery. It's not...what it is doing is ensuring that the computer has an accurate measure of the battery's real capacity.

Now that I think about it, you're probably right.

There is so many differing opinions on this subject. We need a battery chemist to set us all straight.

 

[hopejr]

I'm shocked that your manual doesn't contain any reference to battery calibration. I'm not an MBP owner, but the online manual (at least the US version) contains a large item on it in the Getting Started section. I've never seen anything about C2D machines not needing calibration, so if you have a link, I'd love to read up on it.



I don't buy this at all...there's a reason that periodic calibration is a standard recommendation in the lithium-ion battery industry. Some people calibrate their battery and find that they have a lower capacity than they did before the calibration, which leads them to believe that calibration is hurting their battery. It's not...what it is doing is ensuring that the computer has an accurate measure of the battery's real capacity.

I don't have a MacBook Pro, just a plain MacBook (white one - see sig). I wanted to know if I needed to calibrate my battery when I first got it, and searched the manual and found nothing. I'm serious.

IIRC, MacBooks and MacBook Pro's don't use lithium ion batteries. I think they use Lithium Polymer which shouldn't be calibrated. I agree that calibration is required for lithium ion, as that's what kept my iBook battery in good condition.

EDIT: They do have lithium polymer. See the spec pages for MacBook Pro and MacBook. So don't calibrate you MB or MBP batteries as it does them harm.

 

[andriella]

I have a Core Duo Macbook that I purchased in mid-September. And yes, I am starting to see a small, yet noticable, decrease in my battery life.

In my manual, there is most definitely a page about battery calibration; it says to be sure you calibrate within the first week of using the Macbook. If calibration decreases battery life, why would Apple recommend it? That really doesn't make sense to me.

 

[pianoman]

battery calibration does not decrease battery life. it ensures that the computer software is getting the most accurate information from your battery.

what i think you should do: don't worry about battery life so much. if you need the battery to last long, set the energy preference to "Better Battery Performance", turn down your screen brightness, turn off BT and Airport if you don't need them and go from there. these things, not battery calibration, matter more to the life of your battery on a day-to-day basis.

take your charger to class with you and sit near an outlet if you're concerned. or charge up during a lunch/study break.

 

[hopejr]

I have a Core Duo Macbook that I purchased in mid-September. And yes, I am starting to see a small, yet noticable, decrease in my battery life.

In my manual, there is most definitely a page about battery calibration; it says to be sure you calibrate within the first week of using the Macbook. If calibration decreases battery life, why would Apple recommend it? That really doesn't make sense to me.

I just read through my manual again, and can confirm there is absolutely nothing in it about battery calibration. Note that I have a Core 2 Duo MacBook (not Core Duo).

As I have said earlier though, Lithium-ion batteries should be calibrated, so that's why Apple recommends it for those. I calibrated my iBook battery frequently because it was in the manual for that. It is quite possible that only the Core 2 Duo notebooks have the Li-polymer batteries.

 

[ready2switch]

All batteries lose some charge as they are used, though how fast they will lose charge is dependent on the type.

Battery calibration doesn't effect your charge loss. It doesn't harm your battery. It simply a way for your computer to know "this is empty, this is full" and it can then tell you more accurately what your current charge is.

Yes, the core 2 duo (merom) laptops have a different battery than the core duo (yonah) laptops, and so would explain the discrepancy in the manual about calibration. This is not to say the merom batteries won't lose charge, it just means that the computers monitoring software doesn't need periodic callibration in order to give you a more accurate reading.

 

[WildCowboy]

I just read through my manual again, and can confirm there is absolutely nothing in it about battery calibration. Note that I have a Core 2 Duo MacBook (not Core Duo).

As I have said earlier though, Lithium-ion batteries should be calibrated, so that's why Apple recommends it for those. I calibrated my iBook battery frequently because it was in the manual for that. It is quite possible that only the Core 2 Duo notebooks have the Li-polymer batteries.

Hmm...the original Core Duo MacBooks also had lithium-polymer batteries, but I don't know if there are any other differences between them.

I just pulled up the US owner's manual for the C2D MacBook and confirmed that it no longer directly mentions anything about calibrating the battery. However, I suspect that it was removed as part of an effort that simplified the owner's manual by reducing its size by 50 pages, as the battery section now directs you to Apple's battery page for more tips. That page clearly mentions calibration as standard maintenance and makes no distinction between the batteries used in any of the models.

 

[buffalo]

Apple's battery calibration page lists all MacBook models... It doesn't specify CD vs. C2D.

 

[smueboy]

Since Apple calls the Lithium-polymer batteries a category of Lithium Ion batteries, i guess that they still recommend calibration of these:

http://docs.info.apple.com/article.html?artnum=303785

"Learn about what Lithium Polymer batteries are and how they fall under the category of Lithium Ion batteries.

The MacBook and MacBook Pro computers come with Lithium polymer batteries. Lithium polymer is an implementation of the Lithium ion battery chemistry. Lithium polymer still uses lithium (Li) ions to shuttle energy during charge and discharge.

While the physical battery inside your MacBook or MacBook Pro may state on the underside of the battery that it is "Li-Ion", it is using the Lithium polymer implementation of this technology."