Question Power delivery on normal USB port

Oct 20, 2020
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Hi,

Probably a noob question, but have a Lenovo X1 Carbon laptop and a Dell WD15 docking.

The power adapter from Lenovo is 65W and the WD15 docking only delivers 60W to non Dell laptops. Probably because of that lack of power, I see constant Windows events of new hardware detection and that's affecting my work as the system freezes when that happens.

I was thinking in using the Lenovo power adapter to power the laptop and connect the WD15 on a different USB-C port that doesn't accept power.

Will that cause any issues? Can I plug the USB-C cable that comes from the docking and that can carry up to 60W of power into a USB-C port that doesn't accept power?

Thanks,
Mike
 

Barty1884

Titan
Moderator
Will that cause any issues? Can I plug the USB-C cable that comes from the docking and that can carry up to 60W of power into a USB-C port that doesn't accept power?
That should be fine. The device requests power, and the dock/charger etc supplies as requested (hence you can use over-spec'd chargers and they'll charge the same as using a lesser/more appropriate charger). Neither the charger, nor dock are going to push power through a port that's not asking for it.

Out of curiosity, what power brick are you using with the WD15? From what I can find, in order to provide 60W to non-Dell laptops, the bring 'in' to the dock needs to be providing a minimum 130W.

I'm not sure if there's a <130W option out there (a quick Google search would suggest no), but it's worth checking.

Two additional thoughts:
  • The non-powered USB-C port... does it support display out? That seems to be a prerequisite for using the dock.... not sure if it can function in strict 'data transfer' mode.
  • Assuming at least one support thunderbolt (for display out etc), are your TB drivers/controller up to date?
 
Oct 20, 2020
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That should be fine. The device requests power, and the dock/charger etc supplies as requested (hence you can use over-spec'd chargers and they'll charge the same as using a lesser/more appropriate charger). Neither the charger, nor dock are going to push power through a port that's not asking for it.

Out of curiosity, what power brick are you using with the WD15? From what I can find, in order to provide 60W to non-Dell laptops, the bring 'in' to the dock needs to be providing a minimum 130W.

I'm not sure if there's a <130W option out there (a quick Google search would suggest no), but it's worth checking.

Two additional thoughts:
  • The non-powered USB-C port... does it support display out? That seems to be a prerequisite for using the dock.... not sure if it can function in strict 'data transfer' mode.
  • Assuming at least one support thunderbolt (for display out etc), are your TB drivers/controller up to date?
Thanks for your reply.

I'm using the 130W power brick with the dock. From what I know, only 130W and 180W are available from Dell, but both only provide 60W to non Dell devices and I suspect this frequent USB device detections are caused because of that.

The two USB-C on the X1 Carbon are Thunderbolt, so it supports display out and yes, drivers are up to date.

I'll test later today using the Lenovo charger and the dock on the other port.

Thanks,
Mike
 

Barty1884

Titan
Moderator
I'm using the 130W power brick with the dock. From what I know, only 130W and 180W are available from Dell, but both only provide 60W to non Dell devices and I suspect this frequent USB device detections are caused because of that.
Yeah, I could only see 130 and 180W from Dell - but just wanted to rule out aftermarkets that may not do 130W, as it appears the dock 'reserves' 70W to power devices via the dock). On a Dell laptop, the TB port(s) is probably configured to supply to supply the TB3 spec'd 15W back to the dock as/when required, so can pull more for charging via the dock..... Mere speculation on my part there, but there are benefits to being in the same ecosystem.

The two USB-C on the X1 Carbon are Thunderbolt, so it supports display out and yes, drivers are up to date.
And yet only one accepts power? That is rare, as far as I know..... but definitely possible.

On the offchance both TB ports accept power, try the dock & power connected to the other port.
You're looking at an issue with the dock providing 60W, or an issue with the port on the laptop.

Testing will likely verify it's an issue with 'only' 60W via the dock either way, although it is possible you're not making great contact in the TB port. Less likely to get dust/fluff build up vs something like a cellphone, but possible.
 
Oct 20, 2020
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Yeah, I could only see 130 and 180W from Dell - but just wanted to rule out aftermarkets that may not do 130W, as it appears the dock 'reserves' 70W to power devices via the dock). On a Dell laptop, the TB port(s) is probably configured to supply to supply the TB3 spec'd 15W back to the dock as/when required, so can pull more for charging via the dock..... Mere speculation on my part there, but there are benefits to being in the same ecosystem.
Yeah, when I use the dock with my Dell XPS 13 it all works fine. Only gives problems with the Lenovo X1 Carbon, but that's the company laptop and not changing the dock to a third party one because of that.

And yet only one accepts power? That is rare, as far as I know..... but definitely possible.

On the offchance both TB ports accept power, try the dock & power connected to the other port.
You're looking at an issue with the dock providing 60W, or an issue with the port on the laptop.

Testing will likely verify it's an issue with 'only' 60W via the dock either way, although it is possible you're not making great contact in the TB port. Less likely to get dust/fluff build up vs something like a cellphone, but possible.
Might be that both will accept power... I'm making assumptions as one of them as a plug symbol and the other only has the thunderbolt symbol, but checking Lenovo website, the one that also has the plug symbol is "always on" and that might be why that symbol is there and not to indicate is the only port that accepts power.

I'll try to plug the dock on the thunderbolt only port to see if it charges the laptop or not and take it from there.

Thanks
 

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