Battery reduces for no reason?

Discussion in 'MacBook Pro' started by gusious, Sep 18, 2008.

  1. gusious macrumors 65816

    gusious

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    Dec 2, 2007
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    Greece
    #1
    Hi.

    I have a MBP and i'm running it with it's battery but also the adaptor connected to it so as you can understand the battery is always full.

    When i go to sleep i turn off my MBP and unplug the adapter from the power.

    When i wake up i plug it back again to the socket.

    In the whole procedure the battery remains full.

    BUT sometimes,when i wake up and turn it on with the adapter,the light goes ambient and when i check the condition of my battery it says that it's 95% full.

    Is this normal?Or is it because of the battery or the adapter?
     
  2. gusious thread starter macrumors 65816

    gusious

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  3. Eidorian macrumors Penryn

    Eidorian

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    Indianapolis
    #3
    My MacBook is on the AC all the time. The battery still leaks some charge down to about 95% before it starts charging to 100%. It's normal. The battery loses a little of its charge even when not in use.
     
  4. Digital Skunk macrumors 604

    Digital Skunk

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    #4
    This is true, but OP, your battery habits are deplorable. You should unplug the machine when in use, and drain the battery. Then once it's dead plug it back up and full charge it.

    Repeat the process until the end of the battery/machine's life.
     
  5. gusious thread starter macrumors 65816

    gusious

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    #5
    So i should never leave it with the adaptor on? Only when charging?
     
  6. Icewind macrumors regular

    Icewind

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    Scotland
    #6
    I think what Skunk is saying is that by having your MBP charging all the time, you are reducing the overall life-span of the battery. Its "healthy" for the battery to be drained fully then charged back up. This keeps the "juices" flowing and is sort of like exercising your battery. Keeping it plugged in makes the battery lazy (couch potato). By unplugging your MBP from the charger, you are making your battery "work" and by doing so, it will stay fitter for longer :D
     
  7. Digital Skunk macrumors 604

    Digital Skunk

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    #7
    Exactly. It's like a muscle. The Li-Ion batteries don't have a memory issue as bad as the Ni-MH batts of long ago, but it's still there. Never unplugging it makes the battery get VERY LAZY and then when you do need that battery life you'll only get about an hour and a half.

    Even if you don't move the machine, unplug it when it's fully charged more often that not, doesn't have to be every time, just every once in a while (once a week at least) to keep things moving.
     
  8. Eidorian macrumors Penryn

    Eidorian

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  9. gusious thread starter macrumors 65816

    gusious

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  10. Digital Skunk macrumors 604

    Digital Skunk

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    #10
    Completely as in: The Mac warns you to plug your power cord back in, which is around 5% charge left.

    Or when the Mac goes to sleep.
     
  11. sash macrumors 6502a

    sash

    Joined:
    Nov 23, 2004
    #11
    Hi,

    From Apple's site:

    "For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month."

    http://support.apple.com/kb/HT1490
    http://www.apple.com/batteries/notebooks.html

    sash
     
  12. gusious thread starter macrumors 65816

    gusious

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    #12
    Ok look. Yesterday when i unplugged it my battery said i could use it for 5 hours. I let it charge the whole night and now it says that i only have...wait... 3 seconds before it said 3.5 hours and now it sais 4.54.... What?:confused:
     
  13. sash macrumors 6502a

    sash

    Joined:
    Nov 23, 2004
    #13
    It's normal as the power consumption differs from task to task. And to start-up your machine battery looses a chunk of accumulated energy.
     
  14. Tosser macrumors 68030

    Joined:
    Jan 15, 2008
    #14
    Yesterday evening (8 hours ago) I shut down my MBP while having the plug attached, then I unplugged.
    Today, after start up (still no plug attached) it was down to 72 percent. And now, half an hour later, it's down to 48 percent.

    Edit: After posting this, it is now up to 50 percent. It's becoming the norm with leopard, that new bugs are introduced with every new update. I'm pretty sure my my battery readings are utterly wrong
     
  15. Digital Skunk macrumors 604

    Digital Skunk

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    #15
    You might want to take that in. Leopard hasn't given me any battery issues, but I have noticed with my book that I can put it to sleep at 80%, carry it around for about two hours, the sit at Starbucks and open it up and the book will have a dead battery. Sometimes it will be fully charged then dead when it wakes.

    Happens ever so often, not too much to be without my machine, so I just get through it.
     
  16. wesrk macrumors 6502a

    Joined:
    Nov 4, 2007
    #16
    seems to be exactly what was happening with mine, only your situation seems like it has happened a few times, for me it started about 2 weeks ago, I would put it to sleep at my home and then an hour later open it up in class and it would have like 30% left, other times it was still around 80%.

    Then last week I started taking it to school with a full charge, and the battery would last only 2 hours, then last wednesday only a little bit over an hour.

    After a call with apple care they decided I could get a replacement battery.
     
  17. Digital Skunk macrumors 604

    Digital Skunk

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    #17
    Yup, that's definitely a battery issue if the life is deteriorating that rapidly. For me, it was just a sudden decrease while (I suppose) it was sleeping. I don't like putting the machine to sleep at 70% to have the battery be drained an hour later.

    But, I never had any issues with it while it was awake. I get a good 4 hours out of my 17" Penryn while running Aperture, iWeb and Safari with WiFi on consistently.
     

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