7 Replies Latest reply: Apr 27, 2013 9:38 PM by John Galt
DesertRatR Level 1 Level 1 (10 points)

Preferences indicates battery is fully charged.  Battery icon shows MBA plugged in to power, but charge levle is stuck at 95%.  Is there some way to reset it so it shows proper charge?


MacBook Air, OS X Mountain Lion (10.8.3)
  • 1. Re: Battery indicator stuck at 95%
    John Galt Level 8 Level 8 (36,305 points)

    It's normal: Mac notebooks: Battery may not show a full charge in Mac OS X

     

    The battery may appear to stop charging between 93 percent and 99 percent.

    This is implemented to maximize your battery's longevity. You can help by running it down about once a month.

  • 2. Re: Battery indicator stuck at 95%
    Bimmer 7 Series Level 6 Level 6 (10,270 points)

    As John Galt has mentioned - it's normal.

     

    I have a Macbook Air and it's doing the same thing - this happens to prevent overcharging your battery once it's fully charged.  The charger shuts down and once you get down to 94%, it'll charge it back up.

     

    See image below - thats the current charge of my Macbook Air - if I unplug it and wait till it's down to 94% or 93% then plug it back in - it will charge back to 100% - this is normal on all Macbooks since I have a Macbook, a Macbook Pro and Macbook Air the behaves the same way.

     

    Screen Shot 2013-04-21 at 8.28.27 PM.png

  • 3. Re: Battery indicator stuck at 95%
    DesertRatR Level 1 Level 1 (10 points)

    I let it sit for a couple of days on battery power, until it shut itself down.  I hooked up the power and turned it on.  After fully charged the icon read 100% when I disconnected power.  I think it is reset.

  • 4. Re: Battery indicator stuck at 95%
    Bimmer 7 Series Level 6 Level 6 (10,270 points)

    DesertRatR wrote:

     

    I let it sit for a couple of days on battery power, until it shut itself down. 

     

    Try to avoid this practice on letting your battery get fully discharged - one day your Macbook Air will fail to turn on and you'll be posting as to why - search this forum and you'll see a lot of people having issues about not being able to turn on their Macbook/Macbook Pro/Macbook Air after their battery got fully discharged.

  • 5. Re: Battery indicator stuck at 95%
    DesertRatR Level 1 Level 1 (10 points)

    Can any battery gurus explain why?

  • 6. Re: Battery indicator stuck at 95%
    DesertRatR Level 1 Level 1 (10 points)

    Can a battery be so dead it won't charge?  i've got an old (mid-2008) Macbook that has been sititng unused for 8 months.  I turned it on and nothing happened.  I plugged in power adapter and LED stays green, never turns orange. when I power it up.  Battery indicator says "replace now".  After several hours no charge at all.

  • 7. Re: Battery indicator stuck at 95%
    John Galt Level 8 Level 8 (36,305 points)

    DesertRatR wrote:

     

    Can a battery be so dead it won't charge? 

     

    Certainly.

     

    A lithium polymer battery has internal circuitry that is intended to prevent it from becoming fully discharged, and electrically isolates the battery from its external contacts when its charge falls below a certain amount. However, even after that occurs its tiny internal resistance causes its state of charge to continue to diminish, just slower than it would if an external load were present. This internal resistance increases with age.

     

    Unlike other types of rechargeable batteries, a Li-po battery that has reached this completely discharged state becomes damaged and cannot be resurrected.