1. UNCMo96's Avatar
    I have this charger:
    https://www.amazon.com/Premium-Smart...cUvbUpU5717249

    It had a USB A QC 3.0 output and a USB-C input output connection.
    The QC3 says 2.4A at 5V while the USB-C says 3A at 5V.

    The phone charges pretty nicely with the QC3 connection and battery pack refills nicely via usb-c (faster than other battery packs I've had that charge via micro USB).

    Is there a reason to use to use a USB C to USB C cable to charge the phone? Will it charge any faster?
    03-19-2017 11:53 AM
  2. D13H4RD2L1V3's Avatar
    The charging speeds are identical. Both are around 15W, with the QC3 one being slightly slower.

    If your phone supports QC3, keep it on the QC3 charger.

    The reason is that QC3 is not designed for USB-C and actually messes with the pins that causes it to fail USB-C specs. If your phone does not use QC3 and instead uses USB Power Delivery, then use the USB-C port and the C -to - C cable.
    03-19-2017 12:05 PM
  3. Jaycemiskel's Avatar
    This is why I just want a device with QC4. I'm not trying to have to worry about cables or anything like that. I want to buy a bunch of USB C to USB C cables and call it a day. Not for this needing different cables every time I upgrade
    03-19-2017 12:28 PM
  4. irvine752's Avatar
    The charging speeds are identical. Both are around 15W, with the QC3 one being slightly slower.

    If your phone supports QC3, keep it on the QC3 charger.

    The reason is that QC3 is not designed for USB-C and actually messes with the pins that causes it to fail USB-C specs. If your phone does not use QC3 and instead uses USB Power Delivery, then use the USB-C port and the C -to - C cable.
    Qualcomm's QC2.0 and 3.0 use variable voltage on the Vbus in order to get more power over the same USB A-to-microB cables. QC 3.0 & even QC 2.0 allow for up to 18W charging over an A-to-microB cable by using different combinations...say 12V * 1.5A.

    18W is no slouch, actually, and right now, that's actually 3W more than the 15W that USB Type-C 3A charging can do. The upcoming QC 4.0 is even a bigger deal promising "5 for 5" ie five minutes on a charger would give you fives hours of charge. The max output is stated to be 28W.

    The difference is that Qualcomm's solution is proprietary, and it takes over the D+/D- (usb data) lines, so that Type-A port can't be used to communicate to your PC at the same time you fast charge which violates the USB Type C outlined protocol.
    03-19-2017 12:36 PM
  5. irvine752's Avatar
    I have this charger:
    https://www.amazon.com/Premium-Smart...cUvbUpU5717319

    It had a USB A QC 3.0 output and a USB-C input output connection.
    The QC3 says 2.4A at 5V while the USB-C says 3A at 5V.

    The phone charges pretty nicely with the QC3 connection and battery pack refills nicely via usb-c (faster than other battery packs I've had that charge via micro USB).

    Is there a reason to use to use a USB C to USB C cable to charge the phone? Will it charge any faster?
    If you need an active data connection, I would use USB C , but if you just need to charge the phone....I would stick with QC 3.0....it's slightly faster & more efficient. QC 4.0 promises to be compliant for data, but that's a couple months away at least. We have to wait for the Snapdragon 835 which comes with a ton of improved features like 802.11 ad, QC 4.0, Bluetooth 5.0 just to name a few.
    03-19-2017 12:48 PM
  6. UNCMo96's Avatar
    Thanks for everyone's help. Another question (maybe newbie-ish). Some of theUSB-C cables are USB 3.0 and some are USB- 2.0. Does this make a different for charging?
    03-20-2017 12:45 PM
  7. irvine752's Avatar
    Thanks for everyone's help. Another question (maybe newbie-ish). Some of theUSB-C cables are USB 3.0 and some are USB- 2.0. Does this make a different for charging?
    Any USB-C cable should work with both USB 2.0 & 3.0. Keep in mind USB-C is just a connector type. They call it C because the shape of the connector looks like a C. The connector type was introduced for use with the USB 3.0 ports & higher, but it also supports backwards compatibility with USB 2.0 ports.

    The big difference will be the ports you use for charging. When you have two items of different specification, the faster will reduce speed to match the slower. USB 3.0 ports typically have about twice the power output of USB 2.0 port, the major difference is the data transfer rates where USB 3.0 is ten times faster.
    03-21-2017 09:59 PM

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