Macbook battery calibration

Discussion in 'Mac Basics and Help' started by andriella, Jan 23, 2007.

  1. andriella macrumors member

    Joined:
    Jun 3, 2006
    Location:
    Ontario, Canada
    #1
    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?
     
  2. hopejr macrumors 6502

    Joined:
    Nov 10, 2005
    Location:
    New South Wales, Australia
    #2
    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.
     

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  3. lamina macrumors 68000

    lamina

    Joined:
    Mar 9, 2006
    Location:
    From Canada, living in Seoul
    #3
    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.
     
  4. WildCowboy Administrator/Editor

    WildCowboy

    Staff Member

    Joined:
    Jan 20, 2005
    #4
    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.
     
  5. lamina macrumors 68000

    lamina

    Joined:
    Mar 9, 2006
    Location:
    From Canada, living in Seoul
    #5
    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.
     
  6. hopejr macrumors 6502

    Joined:
    Nov 10, 2005
    Location:
    New South Wales, Australia
    #6
    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.
     
  7. andriella thread starter macrumors member

    Joined:
    Jun 3, 2006
    Location:
    Ontario, Canada
    #7
    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.
     
  8. pianoman macrumors 68000

    pianoman

    Joined:
    May 31, 2006
    #8
    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.
     
  9. hopejr macrumors 6502

    Joined:
    Nov 10, 2005
    Location:
    New South Wales, Australia
    #9
    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.
     
  10. ready2switch macrumors 6502

    Joined:
    Apr 7, 2006
    #10
    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.
     
  11. WildCowboy Administrator/Editor

    WildCowboy

    Staff Member

    Joined:
    Jan 20, 2005
    #11
    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.
     
  12. buffalo macrumors 65816

    Joined:
    Jun 5, 2005
    Location:
    Colorado Springs / Ohio
    #12
    Apple's battery calibration page lists all MacBook models... It doesn't specify CD vs. C2D.
     
  13. smueboy macrumors 6502a

    smueboy

    Joined:
    Oct 30, 2006
    Location:
    Oz
    #13
    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."
     

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