battery charge does not go to 100%

Discussion in 'Mac Basics and Help' started by bki122689, Oct 12, 2008.

  1. bki122689 macrumors 6502

    bki122689

    Joined:
    Sep 18, 2008
    #1
    hey guys,

    So I've only had my macbook pro for 2 months and the battery would charge up to 100%. It would stop at 98%. On Istat it says the health is 99%. Is my lithium battery already starting to go bad? What do you think is the cause of this.

    Thanks
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #2
    No, it's not going bad. The battery health and charge indicators will vary from time to time, up and down. It's not a big deal.
     
  3. bki122689 thread starter macrumors 6502

    bki122689

    Joined:
    Sep 18, 2008
    #3
    So in the future it may charge back up to 100%?
     
  4. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #4
    Yes. The same goes for battery health. Mine might show 92% one day and 97% a week later.
     
  5. Samarium macrumors 6502a

    Samarium

    Joined:
    Jan 6, 2008
    Location:
    @ home.
    #5
    You should calibrate your battery about 2 times a month.
     
  6. richard.mac macrumors 603

    richard.mac

    Joined:
    Feb 2, 2007
    Location:
    51.50024, -0.12662
    #6
    the battery trickle charges (goes down then up) so the battery doest sit on 100% the whole time when fully charged and plugged in. discharge it to below 90% then back to full and it should say 100%.
     
  7. SnowLeopard2008 macrumors 604

    SnowLeopard2008

    Joined:
    Jul 4, 2008
    Location:
    Silicon Valley
    #7
    Yea, it scared the crap outta me when I saw the mAh was 4800 when like an hour before it was 5208. It goes up and down. Just let it drain all the way below 95% and recharge. It will go back up to 100%. And unless the battery goes below 50%, it does not count as a cycle. Although it's best to calibrate the battery every few months or so (no need for twice a month) to even it out. To calibrate, just let it drain until it shuts down. Then recharge back to 100%.
     
  8. gusious macrumors 65816

    gusious

    Joined:
    Dec 2, 2007
    Location:
    Greece
    #8
    Always calibrate. As many times you can. This will keep your battery very very healthy.;)
     
  9. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #9
    Once a month is all that's necessary.... and it's all that Apple recommends. Not even that is necessary if you frequently run on battery, so you're going through cycles anyway.
     
  10. bki122689 thread starter macrumors 6502

    bki122689

    Joined:
    Sep 18, 2008
    #10
    what do mean by cycles? is one considered if it goes below 50?

    and reseting it just drain it all the way down until it shuts down right?
     
  11. bki122689 thread starter macrumors 6502

    bki122689

    Joined:
    Sep 18, 2008
  12. Hands0n macrumors member

    Joined:
    Jan 9, 2007
    Location:
    North Kent, UK
    #13
    Sorry but that is dreadful advice. LiIon batteries do not like to be deep discharged with such regularity. Nor do they like to left on permanent charge while the laptop is in use - it causes heating of the battery which can also shorten its overall life.

    There is so much misinformation about battery care - but tons of good stuff from battery engineers on the web. All it takes is a little googling to find ...

    A worthy reference is here http://www.batteryuniversity.com/parttwo-34.htm
     

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