What power will 2016 MBP draw from 29W USB-C charger?

Discussion in 'MacBook Pro' started by Brookzy, Oct 30, 2016.

  1. Brookzy macrumors 68040

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #1
    I know if you plug a 45W MagSafe into a MacBook Pro that requires 60W, it will still draw 45W from the charger.

    But with USB-C and the Power Delivery specification it all seems a bit more complicated.

    Can anyone confirm what the 2016 MacBook Pro will receive from a 29W Apple USB-C charger?

    To help anyone with knowledge in the area answer the question, here are the output specs of the relevant chargers that I have gleaned from the online MacBook Pro manuals:
    • Apple 29W USB-C Charger: 14.5V, 2.0A or 5.2V, 2.4A
    • Apple 61W USB-C Charger: 20.3V, 3.0A (USB PD) or 9.0V, 3.0A (USB PD) or 5.2V, 2.4A
    • Apple 87W USB-C Charger: 20.2V, 4.3A (USB PD) or 9.0V, 3.0A (USB PD) or 5.2V, 2.4A
     
  2. Brookzy thread starter macrumors 68040

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #2
    Anyone?

    If anyone has one of the non-Touch Bars already, and a 29W charger, maybe they can try it out?
     
  3. JTToft macrumors 68040

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    Apr 27, 2010
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    Aarhus, Denmark
    #3
    The 29 W is the maximum the charger can deliver, so that's what the MacBook Pro will draw.
     
  4. Brookzy thread starter macrumors 68040

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #4
    I'll try to explain what I mean more clearly...

    Of course the maximum the new MBP could draw from a 29W charger is 29W.

    However, it could draw less than 29W in practice because USB-C is far more fussy with its amperage and voltage options.

    For instance, if the late MBP does not support 14.5V, 2.0A (which is possible), then it will fall back to 5.2A, 2.4A mode (i.e. ~12W) and thus the 29W charger will only charge a late 2016 MBP at 12W.

    So, my question is perhaps better expressed as "does anyone know if the late 2016 MBP accepts 14.5V, 2.0A charging?".
     
  5. JTToft macrumors 68040

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    Apr 27, 2010
    Location:
    Aarhus, Denmark
    #5
    - I see. I can't offer anything concrete, but I'd be pretty surprised if Apple hasn't considered this in the design.
    Previously, all MagSafe chargers could be used on all portable Macs without issue and they would deliver their maximum or what the machine required. I doubt that's changed.
     
  6. DBCooper macrumors newbie

    DBCooper

    Joined:
    Dec 14, 2016
    Location:
    Austin, TX
    #6
    All, I tested this, I made a video, I'll post it later, but simply put:

    I was able to get the full 29W on a 13" MBP Touchbar using the 12" Macbook 29W charger. I also tested using the 87W on the 13" and it only yielded 61W. I documented this in a video I'm editing now.

    I also tested the 61W and 87W on the 12" Macbook and it only pulled the 29W. So it seems the MBP's do support the 14.5V@2A spec, it also seems the 61W and 87W support delivering 29W to the Macbook, so presumably the Macbook either supports 20.xV or these 61/87W chargers have 14.5V support in them (I haven't seen that written anywhere).
     
  7. DBCooper macrumors newbie

    DBCooper

    Joined:
    Dec 14, 2016
    Location:
    Austin, TX

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