battery nearly completely uncharged after being unplugged from AC outlet

Discussion in 'MacBook Pro' started by Sossity, Dec 20, 2010.

  1. Sossity, Dec 20, 2010
    Last edited: Dec 20, 2010

    Sossity macrumors 65816

    May 12, 2010
    I usually use my laptop at a desk plugged into an AC outlet. Well I was going to be away for a week, so I unplugged it, when I came back, the battery went from 97%, not charging to 12% when I booted the laptop up again.

    Also, can one continue using a macbook laptop if the battery is dead, but run it through or plugged into an ac outlet all the time?
  2. gnasher729 macrumors P6


    Nov 25, 2005
    The MacBook / MacBook Pro needs a bit of power while sleeping, to keep its RAM running so it is useable immediately. So the battery will discharge. When the battery is close to empty, the MacBook / MacBook Pro will then store the contents of its RAM onto the hard drive instead of letting the battery run out completely and losing the RAM. When you start the MacBook again, it will then read the RAM back from the hard disk, which can take a while, but eventually it will be working as you left it. So if you wrote a document, didn't save it, put the Mac to sleep for a week, that document will be back when you use the Mac again.

    (The new MacBook Air will do the same thing, but I think an hour after you put the MBA to sleep. From then on it will take very very little power to sleep, but waking up will take longer. That's why the MBA should be able to survive up to 30 days in sleep mode without power).

    If your laptop battery is dead, you can still use the laptop with the charger plugged in for as long as you like. No problem at all. You will still have a small amount of battery charge, for example when the charger comes off by accident, it will still last for a bit. Do not remove the battery in that case.
  3. Sossity thread starter macrumors 65816

    May 12, 2010
    There are going to be heavy rains with thunder & lightning forecast for my area for the next 3 days, to protect against a lightening strike & a fry of the laptop, would it be best to unplug it completely from the power strip in my room?

    when the battery eventually dies, how would it be replaced? can it be replaced? or would I have to get a new laptop?
  4. GGJstudios macrumors Westmere


    May 16, 2008
    A power strip should protect your Mac, but it never hurts to err on the safe side. I'd leave it unplugged if you're not using it or if you're using it during a severe storm.
    This should answer most, if not all, of your battery questions: Apple Notebook Battery FAQ. Note the links at the top under BATTERY INFORMATION.
  5. Sossity thread starter macrumors 65816

    May 12, 2010
    Oops, I forgot to mention that when I unplugged the mac from the AC, that the mac was also powered down & shut off as well for about a week, before this the battery was at about 97%, then when I powered it up again a week later, it was down to 12%. How could this be when it was completely powered off & unplugged? does the battery discharge?
  6. GGJstudios macrumors Westmere


    May 16, 2008
    Yes, it does discharge. Please read the FAQ link I posted. It really will answer all your questions.
  7. NickZac macrumors 68000


    Dec 11, 2010
    If you charge the battery as high as it will go and then unplug it, what happens? Does the charge immediately (as in right when you unplug it) flatline? When you went away did you have any devices connected to the MBP?

    To clarify, not all powerstrips provide protection against power surges. The 3-10 dollar power strips do not have any sort of protective circuitry. Furthermore, not all surge protectors are made equal and many of them will not fully protect you against a strong power surge, so unless you know the details about your powerstrip and its capability and limitations, then yes, unplugging the computer during a thunder storm is a good idea. Also, be sure to unplug any other hard wires such as LAN or telephone cords. If after reading this you decide to go purchase a new power strip, consider purchasing one which also provides phone and internet protection as well as they don't cost much more.
  8. Sossity thread starter macrumors 65816

    May 12, 2010
    I did have a USB 7 port hub plugged in as well, into a USB port on the mac, but I unplugged it's power cord from the power strip. I do also have an apple usb keyboard plugged in as well as an ethernet cable.

    I have this power strip;

    another issue is the wiring in my home is very old, my home was built in the 1950's. So my bedroom outlet is only 2 prong, & both the red & green lights are glowing on the belkin strip, for protected & not grounded. I dont know about electricity, so I cannot just rewire my home this is way beyond my abilities, & cannot afford to hire an electrician right now. So what I have done is attached a 2 to 3 prong adapter with a little metal tab that they come with to the faceplate on the outlet with a screw. I dont think it worked as the power strip still indicates with both red & green lights, protected & not grounded, but it was the best I could do. It is my parents house, & I cannot just go tearing into the walls & power lines.

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