Safe to leave power cable on after a full charge?

Discussion in 'MacBook Pro' started by Icaras, Mar 30, 2008.

  1. Icaras macrumors 603


    Mar 18, 2008
    California, United States
    Just wondering if its advisable to keep the magSafe connector hooked up the MBP after the battery is fully charged. Right now I just leave it, but I've always heard that on mobile devices, keeping the charger on after a fully charged battery might actually shorten the life span of the battery. Would this be the case for the MBP too?
  2. NIPRING macrumors 6502

    Jan 19, 2008
    Waukesha WI
    I'm not positive, but i'd bet the farm that it would be just fine. I leave my PowerBook plugged in for days at a time when it gets to full charge within hours of being plugged in.
  3. Deadaim357 macrumors member


    Feb 15, 2008
    Yeah its fine. When I have mine plugged in for a few days it usually drops to 99% or 98%. I just unplug the charger run on battery for a little and let it charge back up. The battery is back at 100%. As long as you sometimes run on battery power its all good.
  4. The Flashing Fi macrumors 6502a

    Sep 23, 2007
    It stops charging at 100%. You'll be fine.
  5. Mo Tiggas macrumors member

    May 5, 2005
    Oregon, USA
    I understand that it doesn't use the battery when plugged in, which would extend the life of your battery significantly
  6. scaredpoet macrumors 604


    Apr 6, 2007
    I've left my MBP plugged in a few days at a time. Your MBP shoul definitely be fine with this.

    However, it will probably be a good idea to make sure you use your battery for at least one full charge cycle once in a while (Apple's support page for batteries recommends at last once a month, minimum). This should keep the battery in good shape.
  7. markrivers macrumors 6502a


    Feb 9, 2008
    Valencia, California
    it's safe.
    but for your battery's sake, use your MBP on battery at least once a week. ad let it drain up to the lowest possible level up to the time your MBP falls asleep.

    this will improve the life of your battery
  8. Icaras thread starter macrumors 603


    Mar 18, 2008
    California, United States
    Ah right. Or in Apple's notes, "Calibrating" the battery, I think. Great, thanks for the tips guys. :cool:
  9. apfhex macrumors 68030


    Aug 8, 2006
    Northern California
    I've left my PowerBook plugged in almost 100% of the time since 2002. :cool: Of course the battery doesn't work anymore. :eek:
  10. atluten macrumors 6502

    Mar 24, 2008
    I'll chime in and say that I have similar results. I mainly use my Powerbook while it is plugged in, since 2004, and even after the monthly battery calibration the battery will only charge to 69%, so I get pretty abysmal unplugged times. Now I wouldn't necessarily attribute this to being plugged in all the time, but just giving a +1 to this type of case. Cheers.
  11. alphaod macrumors Core


    Feb 9, 2008
    Yes it's safe.

    Just calibrate it once a month at least.
  12. iBookG4 FTW macrumors member

    iBookG4 FTW

    Dec 23, 2007
    Newer batteries (from about 2005-06 onward) are ok to leave plugged in all the time. Older ones aren't.
  13. robanga macrumors 68000


    Aug 25, 2007
    Most of the more modern devices have battery technology that has a circuit that essentially shuts down input when it reaches full. This avoids "overcooking" the chemistry in the battery and hurting its overall life.

    There were earlier technologies used in some older devices that did not have this feature. I believe these were Nickel Cadmium or maybe NiMH batteries used in some cel phones and computers, that did not have this feature and so you could indeed overcook the battery by leaving it plugged in all the time.

    Since the advent of Lithium chemistry and the improving battery circuitry this is now a thing of the past.
  14. Maxxx85 macrumors member

    Jan 31, 2008
    I would let mine charger to 100% and then leave it connected for a while then just un-hook the cable and let it drain. After reading what you guys are saying seems it's safe to just leave it plugged in. My batteries health is at 97% after a month, give or take, almost of having the new Per. MBP.

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