T450s slow USB charging Android smartphone when powered on (Samsung Galaxy Note 4)

[Spamkit]

Hi folks,

I use T450s in conjunction with Samsung Galaxy Note 4. Laptop is on AC power. If laptop is turned off the smartphone charges in AC mode (fast charging with about 1A). When I turn the laptop on by pressing power button it switches to USB charging mode (slow, max. about 500mA). Smartphone is connected to always on USB port. Is there a trick to let it always charge in AC mode?

TIA

[Stargate199]

I have a Note 4 as well. I don't normally change off the computer. I will test this and see if I can come up with anything, but I would guess that this is something the computer does because of power management. It probably doesn't have the power to spare for the full 1.0A while running and defaults back to 500mA (standard USB power).

[hhhd1]

maybe an error in detection on the smart phone side.

is there actually significant difference in charge time ?

[Stargate199]

There would be a significant difference in the charge time, almost twice as fast since it can draw 2X the current to charge the battery. The Note 4 does support Qualcomm's quickcharge 2.0, but I'm pretty sure that utilizes 9.7V vs the 5V that is normally used on USB.

It's up to the phone/tablet hardware to utilize the extra amperage.

[Stargate199]

okay to report on this, I can't really tell if there is a difference between the charge time. I've used the power usb port on the computer itself and the power usb port on an ultra dock. Seems to make no difference with the computer powered on or off. Do you have the latest UEFI firmware on your T450s?

[bhendin]

Wonder if anyone here ever got more info?

I've posted a similar thread here regarding my W530.

Ideas?