mbp 15' gets really hot when charging

Discussion in 'MacBook Pro' started by iamvincent, Apr 23, 2010.

  1. iamvincent macrumors member

    Feb 6, 2010
    Got this new mbp a couple months ago, and these it's getting very hot when plugged in charging. Could anyone here help me explain this please? Is this normal, or should i worry about it? BTW, i have it connected to an LED display 24' and the charger is actually the wire of the display. I dunno if this is the reason. THX
  2. OGDaniel macrumors 6502a


    Dec 24, 2009
    Yeah it is. The electrons in the battery and all that nonsense. You should feel how hot my small little shuffle gets when charging...
  3. Pax macrumors 6502a

    Dec 12, 2003
    No, it shouldn't get hot. Heat is very bad for the battery & it's designed not to get hot.
    Are you talking about charging while using, or charging while it's asleep?
    If it's the former, it could be the CPU working hard
    If it's the latter, it should be stone cold while charging, hardly above room temp

    Where does it get hot? (eg near Magsafe plug, on palm rest, etc?)
  4. iamvincent thread starter macrumors member

    Feb 6, 2010
    It's near the Magsafe plug. I think it gets REALLY hot when running, but I havn't
    paid attention to if it gets hot when charging during sleep mode.

  5. Pax macrumors 6502a

    Dec 12, 2003
    OK then I think you have a technical problem, that area shouldn't be hot. My 13" is charging at the moment and around the Magsafe is stone cold.

    I would be concerned about the safety of using it, there might be a fire risk. Even if there is not, I guess there's a chance of long term damage especially to the battery.

    Therefore if it was me I would
    - never let the Mac out of my sight while I was charging it
    - disconnect it from the charger whenever I left it alone
    - contact Apple ASAP

    I think there have been a few others with similar problems coming on these forums. You could use MRoogle to see if you can find anything.

    It could be something as simple as crud on the Magsafe contacts, or a bad Magsafe unit. We could do lots of diagnostics to work out what the problem is, but I wouldn't take that chance. Talk to Apple.
  6. zentenk macrumors member

    Apr 17, 2010
    mine run hot near the magsafe area as well. Also batteries and the charger always get hot when charging, no matter what electronic. The only instance when it's plugged and not hot is because it's not charging, but the MBP is running directly from the plug.
  7. Pax macrumors 6502a

    Dec 12, 2003
    Yes the wall charger gets hot during charging, it's not very efficient at converting AC to DC, there is some loss has heat.

    Really, the battery should definitely not get hot during charging.
    "The charge efficiency is 99.9% and the battery remains cool during charge"
    Of the ~20 W going into the battery only 20 mW should be dissipated as heat. That's not enough to make any significant heating at all. Heat is very very bad for Li-poly batteries.

    My Mac has been charging for about an hour now (nearly full) and I can feel that the area over the Magsafe is just barely warm, a few degrees warmer than the rest of the case.

    It depends on what you mean by "really hot". Can you comfortably hold your fingertip on it? the other side of your finger? etc

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