Battery Decreases When Plugged In

Discussion in 'MacBook' started by Wicker, Jun 18, 2008.

  1. Wicker macrumors regular

    Joined:
    May 11, 2008
    Location:
    Newcastle upon Tyne, UK
    #1
    Hey everyone,

    I've had my Macbook for about 3 weeks now. Something that I have noticed is that when I have it plugged in for a while (for a couple of days with some sleeps inbetween) the % of the battery will decrease to 98% (shown on the battery icon on the top right). This happens while it is still plugged in and has not been unplugged.

    Once I unplug it and then charge it up again it goes back to 100% and stays there for a while until it restarts the whole process (although it has been at 100% for about a week now).

    I'm just wondering if this is normal behaviour or if there could be something wrong with my battery?

    Thanks in advance!
     
  2. ki2594 macrumors 6502a

    Joined:
    Apr 12, 2008
    Location:
    Carmel, IN.
    #2
    def. normal. I think its because when its done charging, it doesn't draw any more electricity, so it will start using the battery, but then it will charge it back up to 100%. So if you were done charging, and it went down to 98, it probably wouldn't go lower then that since its connected to the adapter and it notices it needs to be charged again. I might be completely wrong, but regardless, its normal
     
  3. MM07 macrumors 6502a

    Joined:
    Feb 10, 2008
    #3
    I agree with the above poster.

    My MacBook does the same thing. I was worried as you are (were) and I found a few posts here that explained that it is normal.

    Mine used to go to 96%. If I want to see 100%, I'll unplug it and let it go to 95%, then plug back in.

    I only have 4 cycles on my battery and it is 5 months old.
     
  4. Wicker thread starter macrumors regular

    Joined:
    May 11, 2008
    Location:
    Newcastle upon Tyne, UK
    #4
    As long as it's normal I'm not really concerned about why it does it :)

    Thanks for your reassurance.
     
  5. flopticalcube macrumors G4

    flopticalcube

    Joined:
    Sep 7, 2006
    Location:
    In the velcro closure of America's Hat
    #5
    The REAL reason it drops is because once it has finished charging, the battery's own internal forces start a slow draining of the power. This is why all pre-charged batteries have a shelf life. They discharge even when not in use. Once the level reaches 96-97% the charging circuit kicks in and tops the battery up.
     
  6. Wicker thread starter macrumors regular

    Joined:
    May 11, 2008
    Location:
    Newcastle upon Tyne, UK
    #6
    Thank you for the explanation :cool:
     

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