AT&T Galaxy S8 USB-C Charging - No Fast Charge??

jeffmd

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When using the dedicated USB-C charger that came with my Microsoft Lumia 950XL the S8+ charges at the same rate as charging from a 2.4A USB charging brick. The Lumia 950XL charges at the full 3A of the dedicated USB-C charger so Samsung definitely didn't build in the higher current rate of USB-C. :-(

The Lumia 950XL doesn't use Qualcomms quick charge which increases voltages up to 9v and 12v at 2.4 amps, it just uses the standard USB-C power configuration for 3 amps. 2 different technologies.
 

Jaycemiskel

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The S8 still carries the 2.0 limitation of no fast charge while the screen is on.
That's if you're using quick charge 2.0. If you're using USB PD, that limitation, supposedly, is not in place. There's another thread where a guy measured the power input and it stayed constant with a USB PD charger whereas it was cut almost in half with AFC or QC 2.0. I was just hoping that I could get another confirmation of that before buying more chargers. He was going to do more extensive testing, but then he just disappeared.
 

jeffmd

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The s8 has no official support for usb pd and only a few thread claims that it does, with as many claims that it doesn't.
 

Jaycemiskel

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The s8 has no official support for usb pd and only a few thread claims that it does, with as many claims that it doesn't.
https://gtrusted.com/review/the-samsung-galaxy-s8-is-multilingual-when-it-comes-to-fast-charging

Yeah, no official, but it will fast charge on it. My device even says fast charging when hooked up to a computer that supports USB PD by USB C. That computer definitely doesn't support Qualcomm quick charge. I'm not questioning whether it supports it, just want to know if it'll fast charge even with the screen on. Maybe I'll buy something to measure it so I can see.
 

Whiskey619

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I just tried this with mine, with the original cable plugged into a fast charge enabled port on my laptop. The phone kept automatically toggling into MTP mode which slows the charging. When I changed it back to charge mode, it just switched back to MTP on it's own. Apparently it seems it didn't believe that I knew what I wanted.
 

Jacy Hung

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My S8 doesn't 'fast charge' with the Nexus 6P's included charger, which is rated at 3A. The "rapid charging" technology for the 6P works insanely fast, but doesn't when using it on my S8. My S8 will only 'fast charge' with the included cable & power adapter.

Also, my power bank, this to be exact, (has support for Qualcomm Quick Charge 3.0) when using the USB-C to USB-C cable from the charger to my S8, it does not show up as fast charging, though shows a 1 hr and 5 minute charge to full from 48%.

I tried plugging in a USB-A to USB-C from the bank to my S8 and it does indeed show up as 'fast charging', with an estimated time of just 60 minutes, which is short 5 minutes from the USB-C to USB-C cable/port.
 

Jaycemiskel

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For some reason qc 3.0 is not backwards compatible with Samsungs implementation of qc 2.0
Incorrect. You're spreading false information. His post is evidence that it IS backwards compatible.

My S8 doesn't 'fast charge' with the Nexus 6P's included charger, which is rated at 3A. The "rapid charging" technology for the 6P works insanely fast, but doesn't when using it on my S8. My S8 will only 'fast charge' with the included cable & power adapter.

Also, my power bank, this to be exact, (has support for Qualcomm Quick Charge 3.0) when using the USB-C to USB-C cable from the charger to my S8, it does not show up as fast charging, though shows a 1 hr and 5 minute charge to full from 48%.

I tried plugging in a USB-A to USB-C from the bank to my S8 and it does indeed show up as 'fast charging', with an estimated time of just 60 minutes, which is short 5 minutes from the USB-C to USB-C cable/port.

Only the USB A port on that battery pack is Qualcomm QC compatible. It's QC 3.0. That's why you see fast charging. The USB C port must be USB PD. Some people get fast charging notices, some don't. I've gotten fast charging from a computer with USB PD. From the article I posted earlier, it looks like it pulls similar power so I wouldn't worry about it not saying fast charging.