Overcharging the MBP battery

Discussion in 'MacBook Pro' started by Buzz Law, Nov 22, 2008.

  1. Buzz Law macrumors newbie

    Nov 16, 2008
    I tend to leave my MBP connected to the charger even after its fully charged. Is there any harm in this?

    I remember overcharging problems with cell phones, I'm not sure if the same rules apply.
  2. Tallest Skil macrumors P6

    Tallest Skil

    Aug 13, 2006
    1 Geostationary Tower Plaza
    I've never heard of "overcharging" anything. It's not really possible; you're fine.
  3. vandozza macrumors 6502a


    Jun 14, 2006
    towards the "end" of the charge cycle, you might notice that going from (say) 95% to 100% charged, is much slower than going from 90-95% charged (or any other 5% charge increase.)

    the PMU slows down the rate of charging to a "trickle charge" towards the end of the charge cycle.

    it's designed to do this to avoid any overcharge issues. it's perfectly safe to leave the power cord attached all the time (although at least monthly you should run the battery through a complete discharge/recharge cycle to promote battery health/life)
  4. Buzz Law thread starter macrumors newbie

    Nov 16, 2008
    Thanks for the responses.

    And Tallest Skill, you can definitely overcharge your cell phone battery.
  5. iphonematt Guest

    Jul 10, 2007
    You can??? I have had many phones over the years and have never overcharged my battery. Most Lithium-Ion batteries will cut the power off when fully charged. My iPhone has been plugged in for days before and I never ran into a problem.
  6. RITZFit macrumors 65816


    Sep 16, 2007
    In my Corner
    My mbp has spend the majority of its two yrs plugged up at my desk. Battery still works fine
  7. abijnk macrumors 68040


    Oct 15, 2007
    Los Angeles, CA
    Only if your phone is old enough to not have a lithium ion battery. Lithium ion batteries have protection against that, hence it not being a problem with your MBP.
  8. Shawn Parr macrumors regular

    Oct 31, 2008
    If your phone has a Lithium battery (i.e. LiION) this is unlikely, as overcharging them leads to fire and/or explosions.

    Many batteries now contain logic inside the battery itself to help regulate the input and monitor the temperature to help keep that from happening.

    Now if you have an older phone with an older type of battery (NiMH, NiCd, etc) yes you can overcharge them and it hurts their useful life.
  9. skye12 macrumors 65816


    Nov 11, 2006
    Austin, Tx
    You can't overcharge these batteries. However, it is recommended you
    exercise the lithium ion batteries once a month by letting it run down.
    You don't have to let it run all the way down either.

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