Increased fan speeds during charging ??

Discussion in 'MacBook Pro' started by Joko, Mar 18, 2008.

  1. Joko macrumors 6502


    Jan 30, 2008
    Can anybody tell me if it's normal for the MBP's fans to spin much higher and more erratically when charging? It seems to behave once fully charged, but prior charging while running apps increases fan speeds significantly.

    I've tried many things to try fix it, pram etc but it still does it. It sometimes gets stuck at 6000rpm even after quitting any apps with nothing unusual in the activity monitor.

    The only way to bring the fans down is to unplug the charger, it has done this with 2 different chargers.

    Is this behavior normal?

  2. snaky69 macrumors 603

    Mar 14, 2008
    I don't know if it's normal as I don't own my MBP yet, but I can tell you that charging a battery does generate quite a bit of heat, maybe that's why your fans are acting up?
  3. jofus macrumors member

    Feb 27, 2008
    My fans spin right around 2000rpm when charging (and when idle with no charger hooked up). I'm on a 15" Penryn 2.5.
  4. creator2456 macrumors 68000


    Jul 10, 2007
    Do you have any fan controlling software installed? Some allow you to set defaults for power status changes (charging, battery only, and charged).
  5. Joko thread starter macrumors 6502


    Jan 30, 2008
    Thats interesting, thanks. I didnt know that. I dont have any at the moment. I've only heard of SMC which i tried and didnt seem to have much flexibility.
    Any others you'd recommend?
  6. sjb macrumors regular

    Jul 3, 2007
    My Penryn MBP fans stay at the idle speed of 2000RPM when charging. What revision of MBP do you have? You don't have it on a bed or other surface that would trap heat while charging, do you?
  7. DaveTheGrey macrumors 6502a


    Dec 28, 2003
    This is definitely not normal! Call Apple.
  8. Dustman macrumors 65816


    Apr 17, 2007
    Define erratic. When plugged in, it will run a little bit hotter because of the power supply doin it's work (especially when charging)
  9. Joko thread starter macrumors 6502


    Jan 30, 2008
    Thanks alot for the replies.

    To put it another way: Lets say i run the machine at 75% CPU when disconnected, fan speeds will run up to about 4000RPM max. As soon as I connect the adaptor it shoots up to 6000RPM in less than 2 minutes usually. And often the only way to bring the fan speeds back down is by disconnecting the power and its back to 2000RPM in a matter of minutes.

    Ok by erratic fan behavior I mean that it has even done this first thing in the (cold) morning. Basically, even when temps are low it will do it.

  10. e12a macrumors 68000


    Oct 28, 2006
    When the computer is plugged in it generally runs hotter than being unplugged. I'm not totally sure, but something is down clocked when unplugged. I'd like to think it is the GPU (expose is choppier unplugged)

    Also, the added heat of the battery charging is going to up the temperature.
  11. Joko thread starter macrumors 6502


    Jan 30, 2008
    Yeah I'm sure there is more heat coming into the machine while charging, but for the fan speeds to rise so far compare to what i've researched on MR so far seems too high. Like I said sometimes it does it even when the machine is cold, from boot up.
  12. e12a macrumors 68000


    Oct 28, 2006
    hmm sounds lke you need to take it in. Have you tried a clean install?

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