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Are there any reasons not to use a 10w ipad charger with a USB->USB-C cable to charge a new MacBook Pro 2016? Have the one charger that came with MacBook but would like to be able to plug in at office, home on road, etc. with other chargers. Thx.

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A 10W iPad charger should in theory work and you would be correct that it would be a slow charge. Well, to be accurate, it would be a horribly slow charge - you are getting a charger that is 1/6th (17%) of what is required (61W).

Will there be a problem? No.

Will it charge? Slowly. Molasses in January slowly. From Apple's web site:

Your Mac will charge from USB-C power adapters not manufactured by Apple if they adhere to the USB Power Delivery specification.

Assuming you are using a genuine Apple iPad charger, it should charge since Apple charges adhere to the spec.

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  • Thx. It won't be my main charger...but I would like to use when the standard MacBook charger isn't with me.
    – Sizzle
    Commented Dec 29, 2016 at 17:28
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    I would take my 61W charger and not the iPad charger. The 61W is compatible with both and will not damage your iPad . The iPad will only draw what it needs. A good rule of thumb is that your charger must be >= to the device draw, not the other way around.
    – Allan
    Commented Dec 29, 2016 at 17:47
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    I just want to add that if you end up using the iPad charger to do this on a regular basis, in the long-term you will damage it (i.e. reduce it's life). Also, I would strongly recommend not doing this while the MBP is running. However, the rule of thumb used by @Allan is 100% spot on and I would be carrying the MBP charger around instead.
    – Monomeeth ♦
    Commented Dec 29, 2016 at 23:18
  • ok. Thx for the advice. Are there any 3rd party chargers you can recommend? I would like to have 2 or 3 chargers available but the Apple one is pretty pricey.
    – Sizzle
    Commented Dec 30, 2016 at 21:44
  • At present, there are no (that I know of) USB-C type chargers with >61W of power. The best one that I have seen is the Anker USB 30W charger It will charge the MacBook, but not the MBP. Chances are they will come up with a charger capable of handling the Pro (61W or 87W). When I find one, I will update the answer.
    – Allan
    Commented Dec 31, 2016 at 12:32
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A 10 watt iPad charger will not charge a MacBook Pro because the MacBook Pro will only charge from a USB power supply that supports "USB Power Delivery" or USB-PD. Apple's website states as such. Even then there may be other conditions that need to be met, such as voltage and current supplied.

No USB power brick under 18 watts, at least none that I am aware of, supports USB-PD. A USB power brick that doesn't support USB-PD might supply power, which will slow the discharge from the battery, but it will not add charge to the battery. Connecting a 12 watt USB power brick to my MacBook Pro will show in System Information as supplying power (at least that's what it looks like to me) but it does not show as charging the battery.

During a power outage I was able to run my MacBook Pro from a 27 watt USB-C charger that was plugged into a portable power pack. With some rather lightweight web surfing I didn't see the MacBook battery run down. This same 27 watt charger was able to charge the battery while the laptop (and I) slept.

Officially that's the story, that a MacBook will only charge from a USB-PD power supply. Unofficially, I have read that people have had mixed results using non-USB-PD chargers to charge MacBooks. Personally I have not been curious or desperate enough to run this experiment myself. My guess is that for this to work the laptop would have to be using less power than the power supply so that there is enough power left over to put in the battery. That means the laptop would likely have to be powered off or asleep.

If you are looking for a travel charger for your MacBook Pro then I'd suggest getting nothing smaller than 27 watts. Anything smaller is unlikely to charge the battery, and if it does it will charge quite slowly.

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  • I can confirm that my MacBook Air operates but does not charge without PD, even if left turned off.
    – Alex
    Commented Oct 31, 2022 at 2:50

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