05-09-2017 09:31 AM - edited 05-09-2017 09:32 AM
I'm using the thunderbolt port for a single connection to a Dell usb-c dock (power in, KVM out, speakers, network, etc.). The 720 charges real slow and the battery status message (in Lenovo Settings app) states that the "AC adapter cannot provide enough power for normal operation of your computer". The Dell usb-c docks are powered with a 180w power supply that provides 60w of power to the computer, which is more than the 45w power supply that comes with the 720. I have tried 3 different Dell docks, including a Dell thunderbolt 3 dock with a 240w power supply.
I have to believe this is an issue with the Thunderbolt 3 driver on the 720 or something BIOS related. BTW, the 720 has Windows 10 pro loaded (updated from the home version loaded by default) and Bitlocker enabled. Don't think these changes have anything to do with the issue.
I purchased Lenovo's thinkpad usb-c dock (which states that it's universal) and hope it charges the 720.
05-09-2017 11:45 AM - edited 05-09-2017 11:46 AM
See Yoga 720 manual - page 11: "Note:For Lenovo YOGA 720-13IKB, the Type-C port may be used as an AC power adapter jack". Also, the power adapter that came with the unit will charge on this port. 3rd, I don't believe a manufacturer can call it a Thunderbolt 3 port unless it's bi-directional and includes charging.
So back to my original post, I'm guessing something is going on with the Thunderbolt driver or a BIOS update is needed?
05-09-2017 12:19 PM
Charging can happen at 5v ,9v, 15v or 20v. In general, the laptop will only charge at one voltage, which is negotiated with the charger. Do you know what voltage(s) the dell dock puts out?
05-09-2017 12:39 PM
From what I can find on Dell's website for the WD15, it looks like power output is 19.5v / 3.34a or 65w total? I'm not sure if this is the power output through the usb-c cable or if it's referring to something else. If this is the problem, will the Lenovo thinkpad usb-c dock provide the correct power output for the Yoga 720?
05-10-2017 02:04 PM - edited 05-10-2017 02:06 PM
Received the Lenovo usb-c dock today. It works perfectly... charges laptop and provides all output for kvm, sound, etc. on the single usb-c cable plugged into the Thunderbolt port. Now, if only the power button could turn on/off the laptop without opening the lid!
Note to Lenovo designers: if the 910 could do this on a single thunderbolt port, you would sell millions of them. It's a great laptop but needs the single cable docking solution. Maybe the 920 (if that's what it will be called) will do this?
05-10-2017 02:17 PM - edited 05-10-2017 02:18 PM
Ahh, I missed that. Also, I have the 15" which sadly can't TB charge
[stupid forum software. a quick reply should quote. anyway, i was responding to the page reference for charging the 13"]
06-02-2017 08:48 AM
It's the Lenovo Thinkpad USB-C dock.
Works fine other than the power button on the dock does not turn on the yoga 720. You must lift the screen a tad, then press the power button, then close screen. Worth it for me for a single cable docking solution. My guess is the dock's power button is recognized by the mainboard/firmware on the thinkpads. I have to beleive Lenovo could do the same for the yogas.