The Microsoft Surface Book 2 is a highly portable PC which can be used as either a tablet or a standard laptop through its 2-in-1 design. It has a single USB Type-C port that conveniently supports the USB Power Delivery 2.0 standard which makes it easy for other USB Power Delivery based chargers like the Anker PowerPort+ 5 USB-C with USB Power Delivery to work with this PC.
Here we test charging the USB Type-C port of the Microsoft Surface Book 2 with the Anker PowerPort+ 5 USB-C with USB Power Delivery to explore the USB Power Delivery communication behavior. The following screenshots using GRL-USB-PD-A1 analysis software from Granite River Labs display the power delivery negotiations between the Anker charger and the 30% charged Surface PC.
When connected through the USB Type-C connector, the Anker PowerPort+ 5 USB-C with USB Power Delivery initially offers three PDO's (Power Data Objects): 5 volts, 9 volts, and 15 volts @ 3 amps via USB Power Delivery. Since Anker only specifies up to 35W charging support, the unrated 45 watts (15 volts @ 3 amps) option as seen here might cause the AC adapter to eventually overheat if used during charging which can be dangerous.
We then observe the Microsoft Surface Book 2 requests an initial 39 watts (15 volts @ 2.6 amps) rather than the full 45W from the Anker charger.
After accepting the 39W power request as well as requesting Discover Identity from the Surface PC, the Anker PowerPort+ 5 USB-C with USB Power Delivery further offers an additional 45W PDO of 20 volts @ 2.25 amps on top of the existing three power profiles as declared earlier.
The Microsoft Surface Book 2 can be seen to establish the same 39W power contract with the Anker charger but preferring to use the higher voltage offered in the fourth PDO and using a lower current with 20 volts @ 1.95 amps.
Interestingly, the power graph shows that the Microsoft Surface Book 2 when plugged in only starts to pull current after the 2nd power request, where no charging happens at all during the initial power delivery negotiations as seen above. We can also confirm that the Anker PowerPort+ 5 USB-C with USB Power Delivery delivers around 38 watts (20 volts @ 1.9 amps) to successfully charge the Surface PC while switched on at 30% battery charge.
Be careful though when using this charger with the Microsoft Surface Book 2 or any other notebook PC that tries to draw more than 35 watts. With Anker actually offering 45 watts which is more than the specified 30 watts, there’s a high chance that the AC adapter might eventually overheat when supplying 45 watts which could bring on unwanted safety risks.