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fazalmajid t1_iy1467v wrote

Good question. I tried charging my 12.9” iPad Pro with my USB-A and my USB-C multimeters:

  • USB-C, low-charge mode On: 5V 3A, 15W
  • USB-C, low-charge mode off: 11V, 1.67A, 18W
  • USB-A, low-charge mode On: 5V 1A, 5W
  • USB-A, low-charge mode off: same

Make of that what you will. The USB-A tests were done with an AmazonBasics C-A cable rated at 10Gbps.

You have to manually engage the feature by long-pressing the mode button. Presumably it’s mainly for USB-A since it doesn’t negotiate power like PD does, thus the risk of overload.

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spluga t1_iy1vaou wrote

Thank you for taking the time to test that for me! So the USB-A port appears to limit to 5w regardless of low-charge mode (did you mean the fourth bullet to be USB-A, low charge off?).

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fazalmajid t1_iy1vlgj wrote

Yes, corrected my post. Not sure why it isn't doing the 10W standard USB-A is capable of, even if it can't do the non-standard Apple 12W charging mode at 2.4A. I'll try again with a different power meter and cables.

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spluga t1_iy2bh1h wrote

Yes, 5W and not 10W is surprising. Looking forward to what you find, if you can!

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fazalmajid t1_iy38x04 wrote

OK, I switched to an Apple-branded USB-A to Lightning cable and Klein ET920 tester, verified with an Apple 10W USB charger that it did 5.07V 1.68A on an old iPad Pro with Lightning connector (it was 87% full so probably not drawing at its fullest).

When put on the Nitecore on, it did the same 5.07V 1.56–1.68A whether I turned on slow-charge mode or not. At this point I think it's a placebo, and if you want fast charging up to the rated 18W you must use USB-C, but on USB-A YMMV depending on the cable.

This also confirms my feeling that every power bank maker should adopt the Anker 737's status display feature, and that a USB multimeter is a must-have accessory.

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spluga t1_iy3jk8g wrote

Thanks for the follow up! Agree, agree.

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