I am looking to get a 12V USB charger for my car for the cigarette lighter. I see there are some that offer 2.4A output per USB port with and without Qualcomm Quick Charge, but how does Qualcomm Quick Charge come in to play?

If I don't get one with Qualcomm Quick Charge will I still get the same fast charge rate for my phones or if I want fast charging do I need the Qualcomm Quick Charge?

EDIT: Just to clarify, these devices are phones so they do make use of this "turbo" technology.

  • \$\begingroup\$ Clarify that your devices don't take advantage of this specific quick-charge technology. It might make a difference what you're trying to charge (since 2.4A is outside the formal USB spec, I guess) \$\endgroup\$ – Sean Houlihane Jan 1 '17 at 21:01
  • \$\begingroup\$ Actually, if a device is "a phone", it does not automatically imply that they all will understand your power adapter. To take advantage of QualComm QC technology, your phones must be specifically QC-enabled. \$\endgroup\$ – Ale..chenski Jan 2 '17 at 2:17

The various quick charger technologies work changing the voltage provided by the wall (or car) adapter.

The problem is quite simple: if you want to provide 30W to a tablet to power it and charge it, you need a whopping 6A@5V, i.e. a big expensive cable. If the voltage was, say, 15V, you only need 2A, which is feasible.

At the moment, to use quick charge technology you need matching components: if you have an iPhone it won't use qualcomm QC3 tech, but possibly its proprietary adapter use a different QC standard.

Unfortunately, since rising the voltage is out of the USB spec, what happened is that everybody did their own version, and they are not compatible. This will end with USB C.

If your devices implement some sort of QC technology you need to search for a compatible adapter, or you won't be able to fast charge them.

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  • \$\begingroup\$ I am curious, how all this will end with Type-C connector? What is your vision? \$\endgroup\$ – Ale..chenski Jan 3 '17 at 18:46
  • \$\begingroup\$ It is a bit of a stretch, I am referring to USB PD actually, hopefully all newer devices will support it. \$\endgroup\$ – Vladimir Cravero Jan 3 '17 at 18:56
  • \$\begingroup\$ The PD is insanely complex, and IMHO the cost of PD will be way outside the cost point for Chinese manufacturers (who actually produce all this stuff). Looking at rapid proliferation of QComm QC method (which is vastly simplified yet produces nearly the same result) and global lack of PD devices, it looks more like QC will displace the PD, just as it did happen with "OTG specifications", where only the simplest ID functionality was adopted by mass industry. \$\endgroup\$ – Ale..chenski Jan 3 '17 at 19:10

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