As the MacBook Pro 2016 series supports various USB PD profiles, I'm wondering whether they will also charge using other USB standards, for example:

  • USB Type-C, 1.5A or 3.0A at 5V using the passive marking resistor (not PD)
  • USB Type-A using an A to C cable, connected to a USB BC DCP at up to 1.5 A (for example newer iPhone or most Android compatible chargers)
  • USB Type-A, connected to an iPad charger at 2.1 A or 2.4 A (using Apple's proprietary D+/D- voltage handshake)

I'm aware that most of these will not be able to supply enough power for normal operation of the computer, but being able to charge slowly while in standby would still be useful.

  • I would assume that there is a minimal threshold. For example: a 5V charger would never be able to charge a 10V battery. The adapter provides 20.3V at 3A (or 5A). To change the speed at which the battery charges, you would need a 20.3V adapter at a lower wattage. However, a 5V adapter would not charge a MBP battery. HOWEVER, it is always safest to use Apple's provided adapters and chargers as other ones may be unsafe or cause damage to your computer. – NoahL Dec 25 '16 at 23:57
  • At least the MacBook (non-pro) 2015 seems to be able to charge from some 5 V USB power banks, presumably using an internal step-up converter as its battery will indeed have a higher voltage than 5 V. The question is whether the Pros also support that (and if so, with which minimum current and voltage and using which signalling). – lxgr Dec 26 '16 at 0:03
  • I'd be worried about the converter. The converter is providing a voltage outside of its specs. Why would you want a slow charge like you suggested? – NoahL Dec 26 '16 at 0:07

After some experimentation with a 2016 15" MBP, it seems that they are very flexible:

A USB charger capable of 5 V, 2.4 A proprietary Apple signalling was recognized as providing 12 W of power, and an iPhone charger (which complies the USB BC specification) was shown as providing 5 W. The Nexus 5X charger, which provides USB-C 5 V, 3 A charging, was also correctly recognized as providing 15 W.

The power settings were showing these as "not charging" with the Mac running, but it turns out that even the large 15" MBP is capable of slowly charging from the tiny 5 V, 1 A adapter (it went up by about 2% after charging in sleep mode for about half an hour).

  • where can you see how many watts of power are being delivered? – Kristoffer Nolgren Mar 1 '18 at 15:32
  • Either with a tool like "Coconut Battery" or in macOS's System Information application, under hardware -> power supply (I hope it's called that in English). – lxgr Mar 30 '18 at 15:50
  • 1
    About this Mac -> System Report -> Hardware -> Power -> AC Charger Information in (English) High Sierra. – iKanor Aug 27 '18 at 12:16

I was able to charge my MBP 2017 with the Nintendo Switch power supply, which offers a dual 5V-1.5A / 15V-2.6A output. MacBook negotiates the 15V output and gets 39W of power, which charged my Mac in approximately 3 hours while using it.

Just in case someone lands in this page while trying to find alternatives to a forgotten power supply 😅

  • Thats funny because I found the same exact charger and when i used it on my 2017 Macbook Pro with Touchbar it actually worked AND this was while I was ignorant to minimum power requirements. It seems as if as soon as i started studying power specs the Nintendo Switch charger began to work less and less haha. i think if you have a full charge and use it then you're fine, but you can't ever be running out of charge and expect the Switch's charger to keep you juiced up to where you can continue working, nope. – James008 Jan 18 at 6:44

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