Hot Wall Charger on MBPR ????

Discussion in 'MacBook Pro' started by terrymaz, Jul 7, 2012.

  1. terrymaz macrumors regular

    Joined:
    Aug 3, 2010
    Location:
    SF Bay Area and Chicago Area
    #1
    I received my my MBPR on Monday and noticed yesterday that the adapter for the wall charger seems really hot too the touch. Its not a burn your hand hot but is really warm. My 09 does not do that. I also went to one of my employees and had him chick his 2011 Macbook, his didn't seem warm at all. Is this normal or something i should be concerned with?
     
  2. JoshGlzBrk, Jul 7, 2012
    Last edited: Jul 8, 2012
  3. brand macrumors 601

    brand

    Joined:
    Oct 3, 2006
    Location:
    127.0.0.1
    #3
    There are too many variables that could effect this. Seems like a nonissue.
     
  4. Rajpdx macrumors regular

    Joined:
    Jun 16, 2012
  5. Dangerous Theory macrumors 68000

    Joined:
    Jul 28, 2011
    Location:
    UK
    #5
    I... I don't know where to start...
     
  6. Ddyracer macrumors 68000

    Ddyracer

    Joined:
    Nov 24, 2009
    #6
    Its most likely the retina display that makes it that way. The non retina is probably cooler.
     
  7. TWR Motorsport macrumors member

    Joined:
    Sep 25, 2011
    #7

    I see some of our members have been deprived of a formal education.

    To suggest that electricity conducts heat is intellectually dishonest, electricity is not a tangible item therefore it cannot 'conduct' anything. A conductor is a material which allows a flow of electrical charge. A by-product of this electric charge is wasted energy which manifests itself as heat.

    Oh and in answer to the OP. Yes MPB chargers do get hot :D
     
  8. henry72 macrumors 65816

    henry72

    Joined:
    Jun 18, 2009
    Location:
    New Zealand
  9. heisenberg123 macrumors 603

    heisenberg123

    Joined:
    Oct 31, 2010
    Location:
    Hamilton, Ontario
    #9
    my early 2011 gets hot, don't worry OP its perfectly normal
     
  10. GoreVidal macrumors 6502a

    GoreVidal

    Joined:
    Jun 19, 2011
    #10
    Didn't realize people were so anal. So electricity "causes" heat, but doesn't "conduct" it. Your PHD in electrical engineering has served you well, but us laymans understand what the poster was talking about,.
     
  11. Dangerous Theory macrumors 68000

    Joined:
    Jul 28, 2011
    Location:
    UK
    #11
    Electricity doesn't "cause" heat. Resistance to electron flow results in some energy lost as heat.
     
  12. spdntrxi macrumors regular

    Joined:
    May 11, 2012
    #12
    if the voltage from the receptacle is on the low side (bad or one of those with a switch.. like a dimmer).. this will cause the charger to be HOTTER then normal. Please take it off a receptacle attached to a dimmer or measure the voltage from the receptacle.
     
  13. GoreVidal macrumors 6502a

    GoreVidal

    Joined:
    Jun 19, 2011
    #13
    Okay then, let me translate for a second time. Plugging a power adapter that draws electricity into an electrical outlet gets warm due to heat...I see no layman's difference.
     
  14. mohsy90 macrumors 65816

    mohsy90

    Joined:
    Feb 4, 2011
    Location:
    New York
    #14
    I'd make sure you're plugging it in right. I was at my college the other day and plugged it in and noticed it got really hot. After looking carefully, I noticed that the outlet installed was upside down.

    As mentioned above, it's a variable that could be causing this. That's assuming you're using a North American outlet (NEMA), where the neutral blade larger than the live blade.
     
  15. TWR Motorsport macrumors member

    Joined:
    Sep 25, 2011
    #15
    It gets warm due to the wasted energy from electrical currents. There is a layman's difference because if it is not 'hot' you know there is no power passing through.

    I am disturbed by the fact you think I have a PHD in Electrical Engineering in order to know this...
     
  16. Dangerous Theory macrumors 68000

    Joined:
    Jul 28, 2011
    Location:
    UK
    #16
    It's worrying. I learned this in secondary school. However, maybe I'm biased, since I'm heading on to do a MEng in EEE.
     
  17. GoreVidal macrumors 6502a

    GoreVidal

    Joined:
    Jun 19, 2011
    #17
    I am disturbed by the fact you care so much about this topic to get it so specifically and scientifically correct when any layman should know that when you plug something into a power outlet, heat is bound to be a present after some time.
     
  18. takeshi74 macrumors 601

    Joined:
    Feb 9, 2011
    #18
    Apparently, the OP does not. Be careful with assumptions.

    Nope. My early 2011's adapter gets hot. It really just depends on the power draw at the time.
     
  19. JoshGlzBrk macrumors 6502a

    JoshGlzBrk

    Joined:
    Aug 27, 2009
    #19
    Everyone knows what I meant in the sense that almost all electronics or anything using electricity puts off heat.
     
  20. Pentad macrumors 6502a

    Pentad

    Joined:
    Nov 26, 2003
    Location:
    Indiana
    #20
    LOL! You edited your own post but still got it wrong. Allow me to help you:

    Electricity is a form of energy that may cause items to increase in temperature do to a number of factors. You might want to consult Wikipedia in the future...
     
  21. wethackrey, Jul 7, 2012
    Last edited: Jul 8, 2012

    wethackrey macrumors 6502

    Joined:
    Feb 27, 2007
    Location:
    Redondo Beach, California
    #21
    Ah... no. Assuming you're using the folding two blade plug, the power adapter couldn't give a hoot which of the two pins sees neutral and which sees the phase leg. All it sees is the 115VAC potential between the two blades. This type of plug is a NEMA 1-15P category plug and is non-polarized. You'll note that the two blades are the same size, meaning the power adapter can plug in in either orientation. There's no way for the adapter to tell which leg is neutral and which is "hot". In fact, if you connect a meter between the neutral and hot legs of the receptacle, there would be no way to tell which is which without using the ground leg for reference. All the meter sees is the 115VAC potential between the legs - which is what the power adapter sees.

    The power cord that attaches to the Apple power adapter is a grounded NEMA 5-15P and is compatible with a NEMA 5-15R or NEMA 5-20R receptacle. The ground pin may be connected to the power adapter "chassis" internally in the adapter but there's no measurable connection to either of the power blades. Even if the neutral and phase legs of the receptacle were mistakenly flipped, the power adapter would be none the wiser.

    In any case, the orientation of the Apple power adapter in the outlet is unimportant. Either orientation is correct and neither will affect heat output of the adapter.

    What DOES affect heat output is the current being pulled through the adapter. Two things affect this: power being consumed by the power/charging circuit; and voltage at the outlet. If the computer is powering external loads, like external drives, or if it's under heavy work load, the amount of power (watts) will increase. Assuming a fixed input voltage, an increase in watts increases the current (amp) draw of the power adapter. (Watts = Volts X Amps*)

    As another member pointed out, low voltage at the outlet can also lead to heat at the adapter. If the power (watts) is constant, then a decrease in voltage at the outlet will yield an increase in current (amps). It's also worth noting the Apple power adapters are "universal voltage" adapters. They're rated for any input voltage between 100 and 240VAC at 50 or 60 Hz. They use a "switching power supply" design (based on early pioneering work by Rod Holt for the Apple II, by the way) which maintains constant regulated voltage output from a wide range of input voltages.

    In a more direct answer to the OP's question, Apple power adapters do run "hot" if they're under heavy load. Generally speaking though, assuming you're using the 85W power adapter that came with your MBP, you probably don't need to worry too much about the power adapter being hot. They're both thermally and overcurrent protected. Don't cover them so they aren't being ventilated and don't use a MacBook or MacBook Air power adapter to power a MacBook Pro.

    One thing you SHOULD look out for is fraying at the power cable at the top of the strain relief. Apple is using a much more durable insulation these days but at one point there were a bunch of problems with the cable insulation fraying. The resulting short circuits caused extreme heat with some cables actually burning. Newer power adapters will probably not have this problem.

    Since this post seems to have turned into "all about Apple power adapters", I leave you with this golden nugget of information. If you're there in your dorm room and the game is on and you have a twelve pack of tall ones but not one of your jerkwad friends thought to bring a bottle opener, you'll thank me for this: http://lifehacker.com/5907389/mac-power-adapter-%252B-beer-bottle--apples-secret-churchkey

    * For those engineers reading this, yes I know: Actually Watts = Volts X Amps X Power Factor. But power factor is constant here and including it in the discussion only adds confusion.
     
  22. terrymaz thread starter macrumors regular

    Joined:
    Aug 3, 2010
    Location:
    SF Bay Area and Chicago Area
    #22
    Gosh.....i did not mean to brew up a **** storm on this topic.....Thanks all for the info. :cool:
     
  23. InuNacho macrumors 65816

    InuNacho

    Joined:
    Apr 24, 2008
    Location:
    In that one place
    #23
    It honestly depends on what you're doing. If my 2011 17 MBP is sitting around doing nothing but charging the charger keeps pretty cool but if it's plugged into multiple external drives and monitors with it's fans and processor pumped up it becomes almost untouchable.
     
  24. Trey M macrumors 6502a

    Trey M

    Joined:
    Jul 25, 2011
    Location:
    USA
    #24
    Lol that seems to happen a lot on here...an innocent question turns into who has a PHD, what god you believe in, and who knows what else.
     
  25. terrymaz thread starter macrumors regular

    Joined:
    Aug 3, 2010
    Location:
    SF Bay Area and Chicago Area
    #25

    LOL......I will have to remember that. I believe in the kiss principal. Keep it stupid simple ;)
     

Share This Page