What happens when you plug in a MacBook charger into an iMac?

Discussion in 'iMac' started by afd, Feb 13, 2018.

  1. afd macrumors 65816

    Joined:
    Apr 12, 2005
    Location:
    Scotland
    #1
    Daft question, I know, but have just got a new iMac and need to replace my old USB 2 dock with a USB 3 one. The USB C docks look useful, with HDMI ports and audio ports in addition to USB ones but they seem designed for laptops and I wonder how much power they supply? Could the port rom iMac charge an iPad through the dock or power an optical drive? Some of them can take a MacBook power supply over USB C, which brings me back to original question? Would connecting a MacBook power supply damage an iMac?
     
  2. Brookzy macrumors 601

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #2
    Very confusingly worded question but...

    By the specification, downstream USB-C ports supply up to 15W*. The iMac's Thunderbolt 3 (USB-C) ports can supply up to 15W each. I routinely trickle charge my Retina MacBook overnight by connecting it to my iMac.

    Spec-compliant docks and hubs will do the same, however there are many around that are not spec-compliant.

    Regarding optical drives - in theory they should work, however the Apple USB SuperDrive is hit-and-miss - the seller of a dock/hub usually says whether it will work.

    *By downstream, I mean ports that are connected to devices that are taking power (e.g. an iPad), rather than devices that are giving power (e.g. a USB-C charger, which can supply up to 100W).
     
  3. afd thread starter macrumors 65816

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    Apr 12, 2005
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    Scotland
    #3
  4. nambuccaheadsau macrumors 68000

    nambuccaheadsau

    Joined:
    Oct 19, 2007
    Location:
    Nambucca Heads Australia
    #4

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3 February 13, 2018