GTrusted

The Dell XPS 12 9250 Laptop is a touchscreen notebook-tablet hybrid where everything about its design screams mobility.  

What's more mobile than a car?  Thinking that it would be massively convenient to be able to charge our laptop-tablet hybrid on the way to work or on the way home, we decided to see how well it charged with the Belkin USB-C Car Charger + Cable.

Using software from Granite River Labs, we are able to study the USB Power Delivery interaction between the Belkin USB-C Car Charger + Cable and the Dell XPS 12 9250 Laptop once they are connected together.

First, the Belkin USB-C Car Charger + Cable sends out its Source Capability message several times informing the Dell XPS 12 9250 Laptop that the charger can provide 5 volts or 9 volts @ 3 amps.

Next, the Dell XPS 12 9250 Laptop responds by requesting the first PDO (Power Data Object) to get 5 volts @ 1.5 amps delivered.  

Using an oscilloscope to checking whether the voltage and current was properly delivered, we were disappointed.  Here we can see that the Belkin USB-C Car Charger + Cable delivers 5 volts but the amperage pulled is way too low- roughly 105 mA which is almost nothing.

The Dell XPS 12 9250 Laptop functionally does not recognize that it is being charged, as the screen brightness remains low and the battery icon does not turn into a battery-charging icon. 

Note testing was done with the Dell XPS 12 9250 Laptop's battery being mostly depleted.

Unfortunately, the Belkin USB-C Car Charger + Cable can't be used to charge the Dell XPS 12 9250 Laptop.