XPS 15-9570, Docking Station?

The only docking stations that can properly charge an XPS 15 are the WD15 with a 180W adapter and the TB16 with a 240W adapter.  The reason is that the XPS 15 is designed for a 130W power source, which is greater than the 100W max of the official USB Power Delivery spec.  Dell is doing something proprietary to stretch that to 130W with their docks, but other vendors don't do that, and if they did it's unlikely that their implementation would support Dell systems anyway.  In fact, Dell's own docks say they only provide 60W to non-Dell systems, so you might find similar limitations exist for an HP Thunderbolt dock.  But even without any limitations like that, I don't think I've seen any other docks from anyone that deliver even the official max of 100W over a single standard USB-C/TB3 cable.  All of the other docks I've seen deliver either 60W (the limit for standard USB-C/TB3 cables before you have to get cables rated for 5A/100W), or 87W (to support the 15" MacBook Pro), or no power at all.  So if you wanted to use a dock with insufficient or no power available, you'd have to keep the system's own AC adapter directly connected to maintain proper performance.  Otherwise, you should expect potentially significant performance throttling as the system tried to keep its power consumption within the limits of the undersized power source from the dock.  Under heavy load, you might even find that the system continues to drain its battery even while connected.

And yes, you do need the 180W adapter for the WD15 or the 240W adapter for the TB16 in order to have 130W of power available to pass through to the system, because the docks themselves require some power to run their own internal electronics and maintain a reserve for any peripherals you might attach.  The TB16 in particular has an "upstream" Thunderbolt port that can provide I believe 60W all on its own, which is why it uses higher wattage power adapter options than the WD15.

The main difference between the WD15 and TB16 is that the WD15 supports dual displays only up to 1080p (or a single 2560x1600 display, or a 4K display but only at 30 Hz), whereas the TB16 can support dual displays up to 4K 60 Hz and even some triple display configurations. The reason is that the TB16's use of Thunderbolt gives it access to 4x more video bandwidth than the WD15 has using regular USB-C.

jphughan,

Thank you for the info. Have you had any experience with the TB 16? Would you recommend it as the best docking station for the XPS 15 9570 for now?

Thanks 

> Can I use any TB dock from any manufacturer? If I purchased for example a HP Thunderbolt Dock 230W G2, would it charge the battery and allow me to power on my XPS from the dock with the lid closed?

In theory, yes. In practice, no 3rd-party will feed the 130W required by the 9570 to run without restrictions, because 130W is above the USB power delivery standard max 100W. So you'd need to use a separate power supply. 

Also, the idea of TB3 is that any dock should work with any laptop, but practice is that every now and then there are updates of BIOS, TB drivers and TB firmware. These sometimes cause issues even among same-brand devices. Among different brands, they might never get fixes. Fine if you try using the devices you've got, but I'd only buy a new dock from the laptop vendor or maybe from a reputable 3rd-party which specifically claims compatibility with the laptop model, has agile support and good user reviews. 

The main difference between the WD15 and TB16 is that the WD15 supports dual displays only up to 1080p

Not sure about that. I'm connecting two 1920x1200 monitors to the WD15 (daisy chained DisplayPort).

@mhbuzios  the TB16 documentation indicates that if the TB16 is only powered by a 180W power supply, it can only pass 90W to the attached system.  You need a 240W power supply for it to pass 130W.  The XPS 15 is designed for a 130W power source.  It can function on lower wattage sources, but in that situation you can experience behavior such as slower battery charging and CPU and GPU performance throttling, especially when both the CPU and GPU are under load. 

<ADMIN NOTE: Broken link has been removed from this post by Dell>

@Hrimfaxi  yes the WD15 can run dual 1920x1200, in fact I'm doing that myself with my own WD15.  I mentioned dual 1080p because that's what Dell actually indicates in their documentation and product pages.  They seem to be pretending that 1920x1200 doesn't exist anymore, even though Dell still sells a 1920x1200 display (the U2415, although it is admittedly 4 years old now), or maybe they just didn't want to say 1920x1200 and have everyone ask about 1080p not realizing that 1080p is less than 1920x1200.