Charged Battery looses 1% over night

Discussion in 'MacBook Pro' started by Primusz, Apr 10, 2008.

  1. Primusz macrumors newbie

    Mar 13, 2008
    Hi Everyone,

    I got my MBP 2,5 Ghz Penryn 3 weeks ago and it's my first Mac.

    However I noticed something funny. I work at my desk 99% of the time, with the power plugged in. Ofcourse, the battery should remain fully charged because of this, but when I start it up the next morning, the battery has lost 1% charge.

    How can this happen? I am using the adapter as much as possible to prevent the battery from having to charge and recharge so much, extending it's life.

    Any ideas?
  2. mheidt macrumors member

    Jun 7, 2005
  3. zaney macrumors regular

    Apr 6, 2008
    Middle of a field, UK
    Lithium Ion batteries can be damaged if they're kept at 100% charge, so to prevent this your mac will automatically charge and discharge between about 95-100%, this is normal.
  4. joeshell383 macrumors 6502a

    Sep 18, 2006
    To address your concern, it is nothing to be concerned about! :)
  5. Primusz thread starter macrumors newbie

    Mar 13, 2008
    thank you for this constructive and useful feedback!

    why are you telling me this?
  6. skye12 macrumors 65816


    Nov 11, 2006
    Austin, Tx
    Completely normal. Have a 4 year old battery in a ibook that looses
    3-4% overnight, but still works fine.
  7. zaney macrumors regular

    Apr 6, 2008
    Middle of a field, UK

    No problem, and beware the grammar nazis. I must admit that bad spelling/grammar does annoy me, but not to the extent that I tell people off over loose/lose, which is probably a just typo.
  8. nick9191 macrumors 68040

    Feb 17, 2008
    Don't leave the power plugged in all the time, it guffs the battery.
  9. Eraserhead macrumors G4


    Nov 3, 2005
    I have a theory. Just use the battery however you want, whatever you do damages it, just don't be OCD about it.
  10. leodavinci0 macrumors 6502

    Jan 26, 2006
    The battery contains a processor, which draws a small amount of current from the cells when they aren't being charged. This occurs even when the laptop is plugged in since no power is supplied to the battery during times the battery is not being charged, so the processor needs to draw off from the cells. The processor is on the same circuit board those green LED's are on.

    Edit: Like a previous post above said, it is not good to keep a Lithium ion battery at 100% over long durations. If you don't plan on using it for long durations (e.g. more than a week), drain it to 60%, remove it from the laptop, and store it in cool place (e.g. a refrigerator). This will keep the battery fresh from degradation for months at least, and I've seen data that suggests years.
  11. EngBrian macrumors regular

    Feb 7, 2007
    Ontario, Canada
    As above people had said the battery will allow itself to dip to 95%. Also since you mac is approaching being around for a month it is coming up to the time you might want to cycle the battery if you aren't letting it completely discharge as you go. You may already know about this but just in case the apple doc below lets you know how to do that:

    I do this about once a month my battery is up to 70 cycles and it hasn't lost a mAh in its life yet...cross fingers.

  12. zaney macrumors regular

    Apr 6, 2008
    Middle of a field, UK
    A) He was asking a valid question, you knew what he meant.
    B) Looses and Loses are both valid words, and thus a spell checker won't help.
    C) O -> OO is an easy typo to make.
    D) This is the internet, and thus it's presumptuous to assume that English is someone's first language.
  13. xUKHCx Administrator emeritus


    Jan 15, 2006
    The Kop
    Mod Note: This is a global forum and as hinted by other members in this thread communication is the goal not perfert spelling. Please refrain from commenting on spelling mistakes as it generally derails a thread thus making it harder for the original poster to get answers. I know I spelt (yes it is a word) perfect wrong

    In regards to the original question, IIRC the battery is charged up to 100% and then the charger stops until the charge dips below 95% then it tops it up again.
  14. iCeFuSiOn macrumors 6502a

    Jul 18, 2007
    It is a bad idea to operate your Apple portable without the battery because this will automatically throttle the processor down to one core. As others have said, don't worry about the battery draining down slightly, it is just to protect it from damage.
  15. tobefirst macrumors 68040


    Jan 24, 2005
    St. Louis, MO
    Quite possibly the smartest thing I've heard on MR in awhile. Bravo.
  16. leodavinci0 macrumors 6502

    Jan 26, 2006
    Where did you read this, can you cite it or provide a link to it? I suppose you aren't talking about the "Reduced" option in the Energy Saver system preferences.
  17. Primusz thread starter macrumors newbie

    Mar 13, 2008
    Well, that seams a pretty over-the-top thing to do, and as suggested, it would mean one core would be turned off

    thanks for the link! Is it also applicable for the MacBook Pro?

    thanks for your support guys/gals, but I don't seem to see the word loose and lose being used in my post. Only the world "lost" , which is in the proper context if you ask me?
  18. eluk macrumors 6502a


    Dec 14, 2006
    East London, UK
    In the title. :)
  19. zaney macrumors regular

    Apr 6, 2008
    Middle of a field, UK
    No problem, and welcome to the forums, by the way. The word "loose" was in your thread title, although please don't let all this hassle over it give you an impression of the community. We're all very nice really. :D
  20. Primusz thread starter macrumors newbie

    Mar 13, 2008
    Ah thanks! I was starting to think I needed glasses or something.. Typo indeed..

    Thanks and no worries. Have been keeping an eye on this site for months now, as I wanted an MBP. Thanks to this site I bought one at exactly the right moment (new updated model and last but not least, money on my account :D)
  21. Csmitte macrumors 6502


    Oct 11, 2007
    what he said
  22. pik. macrumors 6502


    Feb 4, 2008
    same here no problem at all everything ok...:cool:

    lost 1% and today on AC is 100%...
  23. alphaod macrumors Core


    Feb 9, 2008
    Mine came at 97% and it has stayed there since I got it (Feb 26--61 cycles).

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