Lenovo Thunderbolt 3 Essential Dock (40AV) USB-C Power Delivery

2 months ago by eco_game to c/thinkpad

TL;DR: This dock only supplies 65 W over it's main USB-C connection, even though it ships with (and probably requires?) a 135 W power supply.

I've recently gotten this Docking Station. Online it says everywhere that it ships with and requires a 135 W power supply, which with most other ThinkPad docks leads to 95 W laptop charging.
I couldn't find any info online whether the Thunderbolt 3 Essential Dock would make use of the extra wattage from the power supply to also charge laptops faster. Now that I have the dock, I can confirm my (Dell) laptop won't charge with more than 65 W from this dock sadly. Same power supply + 40AY docking station shows 95 W on that same Dell laptop.

So yeah, just wanted to put that info out there because I was frustrated not to find it myself. I don't really mind it only charging with 65 W, but I do wonder what the hell it's doing with the 70 W of headroom…

curbstickle 5 points 2 months ago

That entire lineup (gen 1 through 3) I think cap at 65W, the rest of it is to power the other ports.

I had to pick up the new tb5 dock with a 265W power supply to support my newest thinkpad, I'm moving the other dock over to another bit of kit to support my older laptops (t480, x1 yoga, x13), but yeah its only 65W.

The rest is for devices. The USBC ports get a 30W allocation, the USB-A get 15W, the internal controllers another 15W, and the remaining 10W is for the video processing onboard.

save

path: 0 25218793, hotness: undefined, score: 5, children: 2

eco_game 2 points 2 months ago

The 40AY is the second generation USB-C dock, if you pair it with a 135 W power supply it will charge at 95 W.

As you say though, I also just figured it out: unlike the 40AY, the 40AV has two peripheral USB-C ports on the dock itself. Each of them can supply 5 V at 3 A, meaning the dock needs at least 65 W + 2*15 W, which exceeds the lower spec 90 W power supply. And because it likely makes no sense for Lenovo to create more power supplies with (seemingly) random wattages, they must have used the next largest which is 135 W.

save

path: 0 25218793 25221267, hotness: undefined, score: 2, children: 1

curbstickle 2 points 2 months ago

I forgot about the AY! I was thinking about the AC and AN along with the AV. To make it worse, I have an AY about 2' away from me in a bin...

save

path: 0 25218793 25221267 25222319, hotness: undefined, score: 2, children: 0