Because the default power of USB 3.1 is at max. 4,5 Watt I thought I could use a splitter or Y cable for that. The idea is that one USB-A male connector transfers the data (10 Gbit) and power and the other USB-A male connector the power in addition. So you could get 9 Watt out of two ports.

But I only found one cable from CY and here it is one time USB 2.0 only and on the other side they write USB 3.1. Aren‘t there any other options?

Another alternative would be an USB hub. But one with external power supply, 10 Gbit and more than 900 mA per port would start at 90 $ ... (e.g. IB-HUB1477-C31).

Is it really that complicated?

  • "Is it really that complicated?" -- You're trying to find a cable that goes outside the standards for USB-C power delivery. The USB C port you want to power may not be able to safely handle more than 4.5 W of power without using a special mode over USB-C. There are "rules" in the USB standard that keep devices from breaking each other with too much current flowing! Also using two separate USB power sources could introduce an incorrect voltage too. These cables aren't supposed to exist so if you find one, be sure to use both A ends on the same source.
    – Romen
    Jul 24, 2020 at 15:36
  • Thanks for your hints! The USB C port (of the device which will be used) should handle up to 100 Watt according to the manufacturer. Yes, I'll only plug the two USB A ends into one device. But you are right, the devices don't talk with each other how much current they need (as it would be the case with USB PD). Do you think that could work or do you say I shouldn't do this?
    – testing
    Jul 24, 2020 at 16:01
  • If your device "supports 100 W" then that is absolutely using the USB-C special mode for power delivery! Just feeding it extra amps without having the device change modes could cause damage and especially in the case of overheating a battery! Anything other than the standard USB power spec may be detected as "fast charging" or USB-C PD if the device supports it so it might be OK to use this Y cable for some devices.
    – Romen
    Jul 24, 2020 at 17:22


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