Battery Calibration Question - how to know if it's fully discharged?

Discussion in 'MacBook Pro' started by MBHockey, Apr 30, 2010.

  1. MBHockey macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #1
    I have an SSD and since I got it I've always change the hibernate mode of my Mac to '0' instead of '3' via the pmset command in terminal and then I delete the ram-sized sleepimage in /var/vm to reclaim some disk space.

    This means that the Mac sleeps instantly (doesn't write that 4 gb file to the ssd every time the lid is closed) but you lose out on the feature where if you run out of power the computer will be able to restore to that previous state when you recharge it.

    So I got my new MBP yesterday and I used it for about 3-4 hours past full charge and removed the cable. I ran it down all the way and then it eventually just shut itself off after 1% (because hibernatemode is at 0). It didn't go to sleep prior to shutting off, it just went from on to completely off.

    I let it sit over night, not plugged in, and I notice now this morning when I hit the button on the left side of the casing to check the battery charge level it just blinks a single green circle.

    Does anyone know if this means the battery is fully discharged? Or should this LED not come on at all if the battery is really empty? I'm just wondering this because I'm unsure if the battery went through all of its reserve power without the standard hibernate mode. Maybe with the hibernate mode set to 0 it uses all of the reserve power instead of going to sleep when it's almost drained? I guess this would explain why after 1% the computer just shut itself off like if you yanked the power cord out of a desktop (probably not the best thing to do.)

    I just want to make sure my battery is fully discharged before i recharge it.
     
  2. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #2
    There always seems to be some juice left for this indicator. I let some of my Macs sleep for days or weeks, and there is still the blinking battery light.

    To solve the sleep-and-no-sleep-image problem, take a look at SmartSleep, which gives you the option to create a sleep image when there is a set capacity left. I worked for me.
     
  3. MBHockey thread starter macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #3
    Ok thanks, that's good to know.

    I'm not saying it's a problem with the hibernate mode I use. I do it on purpose -- so it doesn't write the 4GB sleepimage to my disk every time I sleep it (I don't think writing that much data so often is great for my SSD.) Also, it sleeps instantly instead of ~10 seconds. I sleep my computer about 15-20 times per day probably so it's nice to have it instantly sleep when I'm on the go.
     
  4. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
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    forlod bygningen
    #4
    I know, my iBook fell asleep in two seconds and awoke in the same time. When I got my MacBook, I brought it back, because I thought it was an error in the system, but the technician said, it was okay, but didn't know why, so I searched and finally came upon this place. SmartSleep offers you several options regarding sleep, one of them is called smart sleep, and it lets your Mac sleep instantly without writing a sleep image, but when the charge drops below a certain set percentage (5%, 11%, 94%, ...) it writes the sleep image so in case of battery emptiness, you can still recover from the now existing sleep image. But I don't know if it gets automatically deleted afterwards, but SmartSleep offers to do it via its preference pane.
     
  5. JTToft macrumors 68040

    Joined:
    Apr 27, 2010
    Location:
    Aarhus, Denmark
    #5
    - That's a great tip. Thanks! :)
     
  6. MBHockey thread starter macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #6
    Oh, I see. So it will only write that sleepimage file to the disk if, say, your battery percentage drops below 5% (or whatever I choose)?
     
  7. spinnerlys Guest

    spinnerlys

    Joined:
    Sep 7, 2008
    Location:
    forlod bygningen
    #7
    Yes.
     
  8. MBHockey thread starter macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #8
    Oh that's great! First time I read your post I misunderstood it. Thanks for the tip!
     

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