I've got a Nexus 5X phone which does not support QuickCharge, but it does support 'fast charging' through a 5V/3A USB Type C charger.

Normally I charge it with a Type C 5V/3A charger, and a USB Type C to Type C cable:

USB Type C 5V/3A Charger + USB C-to-C cable

This works fine. This is the original charger that came with the phone.

Now I'm wondering, what if I get a dual charger like this:
(note that those are two Type A USB ports, not Type C)

USB dual charger

Along with a USB Type A to Type C cable:

USB A-to-C cable

Will this allow me to charge just as fast? And in that case, should I use the QuickCharge 3.0 port, or the 'regular' 5V/3A (non-QC) port? Or can I expect them both to work?

Basically what I'm wondering is:

  1. Can I get my Nexus 5X to fast charge over a Type A to Type C cable as well, provided that the charger does indeed deliver 5V/3A through the Type A output?

  2. The Nexus 5X does not support QuickCharge 3.0. But considering that QC3.0 specifies support for various voltage and amperage ranges including 3.6V-6.5V/3A, could I still expect my Nexus 5X to fast charge through a QC3.0 charger? (which would again be through a Type A to Type C cable)


closed as off-topic by Marcus Müller, DoxyLover, pipe, Dave Tweed Aug 26 '17 at 21:41

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Marcus Müller, DoxyLover, pipe, Dave Tweed
If this question can be reworded to fit the rules in the help center, please edit the question.

  • 2
    \$\begingroup\$ Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design. \$\endgroup\$ – Marcus Müller Aug 26 '17 at 19:24
  • \$\begingroup\$ @MarcusMüller My apologies, upon searching I couldn't find a StackExchange area that seemed more appropriate than here. Would you have any suggestion where I should post this instead? I'll be happy to delete it and try elsewhere. \$\endgroup\$ – RocketNuts Aug 26 '17 at 19:30
  • \$\begingroup\$ try superuser.com \$\endgroup\$ – Marcus Müller Aug 26 '17 at 19:35
  • \$\begingroup\$ @MarcusMüller Thanks, have posted there instead. Can someone close this or should I delete it myself? \$\endgroup\$ – RocketNuts Aug 26 '17 at 19:47
  • \$\begingroup\$ Not going to do an answer post since this is off topic, but in short the answer is no. If the Type-A to Type-C cable is usb compliant, it should have a proper 56 kOhm pull-up resistor on the CC pin which will limit the current to 1 Amp, ensuring safe region for any USB-A host or charger that it is plugged into. \$\endgroup\$ – justing Aug 26 '17 at 19:48

In order to get full charge over Type-A to C cable, the Type-C end of cable must provide 10 kOhm pull-up inside its overmold. Then a Type-C compliant device/phone should be able to take all 3 A. However, this would make this nice short A-C cable illegal, because if someone will use this cable with a regular PC, it might create hazardous overcurrent condition.

Since the Nexus 5X doesn't support QC (no v2.0, nor v3.0), and the QC3.0 port in the QC charger likely doesn't have an alternative BC 1.2 protocol, your phone will rely on CC pin pull-up in the Type-C cable overmold. If the particular QC charger doesn't police the QC protocol and will output the minimum (5 V 3 A), then your phone will take the same current as from any other port.

Therefore, I expect that there will be no difference which Type-A port to use, unless the LG phone/charger uses full-blown Power Delivery protocol. In the latter case your "dual charger" won't work at all, maybe at 500 mA.

To get a practical sense of what difference do you have, I recommend to invest in a USB power meter/tester like this one, with proper voltage range.

enter image description here


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