GTrusted

Henge Docks has been producing a number of vertical and horizontal docks for Apple Mac notebooks including the Stone which also happens to be their first USB Type-C based dock. Since the Stone offers USB Power Delivery based charging through its side USB Type-C port, we decide to try it with the  Apple 15" MacBook Pro (Late 2016) which also supports USB Power Delivery over its Thunderbolt 3 enabled USB Type-C connectors.

Using the Granite River Labs GRL-USB-PD-A1 analyzer app, we can find out easily how much power the Apple 15" MacBook Pro (Late 2016) actually pulls from the Stone when 95% charged on the Mac. But first, we connect one of the Mac's Thunderbolt 3 port to the USB Power Delivery enabled USB Type-C port on the Stone which also provides the same 87 watts based charging as the Mac's own supplied Apple 87W USB-C Power Adapter.

Here we can see through GRL-USB-PD-A1 software that the Stone starts to communicate over USB Power Delivery with the Apple 15" MacBook Pro (Late 2016) by offering only one power profile of 15 watts (5 volts @ 3 amps) after initial Vendor Defined Messages.

With the limited power option, the Apple 15" MacBook Pro (Late 2016) decides to request only 7.5 watts (5 volts @ 1.5 amps) while on a 95% full battery. Once accepted, the Mac then initiates and performs a Power Role Swap with the Stone. 

Later we can see a soft reset occurs to subsequently adjust voltage and current, after which the Stone finally advertises its full power capabilities of 15 watts (5 volts @ 3 amps), 36 watts (12 volts @ 3 amps), and 87 watts (20 volts @ 4.36 amps).  

The Mac eventually selects the max 87 watts (20 volts @ 4.36 amps) option to get the fastest charging with the dock which then accepts.

We next observe the Stone displays a single Sink Capability of 7.5 watts (5 volts @ 1.5 amps) upon the Mac's request.    

After repeating the same sink power, the Stone continues to exchange Vendor Defined Messages which include Discover ID, SVIDs, and Modes with the Apple 15" MacBook Pro (Late 2016).

While the Apple 15" MacBook Pro (Late 2016) is 95% charged and powered on once connected, we can see the Mac trickle charges at first over rapid changing current upon requesting 87W onwards in the above power delivery negotiation. The voltage and current later become more stable to enable around 36.4 watts (20.2 volts @ 1.8 amps) charging power to be drawn. 

With an almost well charged battery, it makes sense for the Mac to draw much lower power than the negotiated 87W. Other than charging the Apple 15" MacBook Pro (Late 2016) properly over USB Power Delivery, the Stone can also be used to easily add USB drives, mice, audio headphones or speakers, Ethernet networking connection, a SD 4.0 UHS-II card, and a 4K@30hz display over mini-DisplayPort to the Mac.