USB Power – How to Show USB Power Usage

powerusb

I wanted to see how much power the Anker Astro external battery draws when charging from the MacBook Pro (Retina, 15-inch, Late 2013) (right hand port next to the SD slot), but when listing the USB info in System Profiler, the battery doesn't show up as a device, it does receive some power though, but I thought to get more than the standard 500mA they would have to register and activate high-power mode (which I expected the battery to do).

Additionally it lists the SD card reader as requiring 896mA, but there's no card plugged in, seems odd that the empty reader would need that much power.

So I don't quite trust the output here, is there another way to list devices / get info from the hubs about how much power they are distributing?

$ system_profiler SPUSBDataType
USB:

    USB 3.0 SuperSpeed Bus:

      Host Controller Location: Built-in USB
      Host Controller Driver: AppleUSBXHCI
      PCI Device ID: 0x8c31
      PCI Revision ID: 0x0005
      PCI Vendor ID: 0x8086
      Bus Number: 0x0a

        Internal Memory Card Reader:

          Product ID: 0x8406
          Vendor ID: 0x05ac  (Apple Inc.)
          Version: 8.20
          Serial Number: 000000000820
          Speed: Up to 5 Gb/sec
          Manufacturer: Apple
          Location ID: 0x15400000 / 12
          Current Available (mA): 900
          Current Required (mA): 896
          Built-In: Yes

    USB 3.0 Hi-Speed Bus:

      Host Controller Location: Built-in USB
      Host Controller Driver: AppleUSBXHCI
      PCI Device ID: 0x8c31
      PCI Revision ID: 0x0005
      PCI Vendor ID: 0x8086
      Bus Number: 0x0a

        Apple Internal Keyboard / Trackpad:

          Product ID: 0x0262
          Vendor ID: 0x05ac  (Apple Inc.)
          Version: 2.25
          Speed: Up to 12 Mb/sec
          Manufacturer: Apple Inc.
          Location ID: 0x14c00000 / 3
          Current Available (mA): 500
          Current Required (mA): 40
          Built-In: Yes

        BRCM20702 Hub:

          Product ID: 0x4500
          Vendor ID: 0x0a5c  (Broadcom Corp.)
          Version: 1.00
          Speed: Up to 12 Mb/sec
          Manufacturer: Apple Inc.
          Location ID: 0x14800000 / 2
          Current Available (mA): 500
          Current Required (mA): 94
          Built-In: Yes

            Bluetooth USB Host Controller:

              Product ID: 0x8289
              Vendor ID: 0x05ac  (Apple Inc.)
              Version: 1.03
              Speed: Up to 12 Mb/sec
              Manufacturer: Apple Inc.
              Location ID: 0x14830000 / 4
              Current Available (mA): 500
              Current Required (mA): 0
              Built-In: Yes

Best Answer

Standard USB output is 500mA.

If a device connected requests more it will be exceptionally given more, up to 1 Amp. (ie Card reader made that request).

If you device is not "identified", and did not make the request, it will get the 500mA.

Here is more information from Apple https://support.apple.com/en-us/HT204377

If you must know the real time current flow you would need one of the devices that do that Example: http://www.amazon.com/DROK-Extension-Multimeter-Connectors-Consumption/dp/B00S2IA3DG/ref=pd_sim_sbs_pc_7?ie=UTF8&refRID=179R1GBKK80252K5HW5V

or this one http://www.amazon.com/AboveTEK%C2%AE-USB-Voltage-Current-Multimeter/dp/B00ICR1UB6/ref=pd_sim_sbs_pc_3/175-5520415-2589050?ie=UTF8&refRID=179R1GBKK80252K5HW5V

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