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I would like to prevent my iPhone draining power from my MacBook Air while the laptop is not plugged in and relying on battery power. How would I do this? Note, there doesn't seem to be any "unpowered USB ports" on the MacBook Air, both of them seem to charge my iPhone even when the laptop is not plugged into a power socket...

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I don't know if there is a software way to do that, but there is an hardware way:

  1. Use an unpowered USB cable (some company makes it, targeting audiophiles), might need an adapter to male lightning.
  2. Tape/Remove the power plugs on your USB cable.

Also, not exactly an answer to your question, but maybe to your use-case: Build a binary, then export it to iTunes, then upload via wifi. No debbuger and much less convenient tho.

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  • Using an unpowered USB cable or blocking the power wires could result in damage to the device. Dec 9, 2018 at 21:08
  • @g.rocket Blocking the power wires improperly might, but using an unpowered USB cable definitely would not.
    – Antzi
    Dec 10, 2018 at 5:34
  • The iPhone was never designed to be connected to USB without the power and ground attached, so it could damage the lightning interface (or possibly the entire device). Dec 10, 2018 at 20:39
  • I don't know if this works on older devices with the 30-pin connector, but I tested it with a device with a Lightning connector and it doesn't work. The Lightning cable has electronics in it that need power from the USB host. The device won't connect. Dec 9, 2022 at 0:44
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Assuming the only other reason that you would connect your iPhone to your MacBook Air other than charging would be syncing. As far as I know there is no way to disable to charging aspect although you can work around it by syncing over WiFi rather than cable. Hope this helps!

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    Thanks, there's another reason, to test apps you are developing.
    – Victor S
    Jun 9, 2014 at 21:57
  • Oh yeah, surprised I forgot that being a developer myself. Sorry about that.
    – rcobelli
    Jun 10, 2014 at 1:14

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