My friend John Obeto pointed out some pre-release coverage of Satechi’s new USB-C power meter a week or so ago. I’ve had a number of different USB-A (standard port) testers and meters for a while, but with more devices coming into rsts11 headquarters with Type C connections (including the XPS 13 9350 and XPS 15 9550, Apple’s 12″ Macbook, the ASUS Zenpad Z10 from Verizon, and the Nexus 6P by Huawei and Google), I’ve wanted to look at power consumption beyond what an A-to-C adapter could reveal.
For those of you new to USB-C, it’s designed (in part) to be a universal connector for power and data, incorporating high speed data in a connector shared with Thunderbolt 3 (40gbit capability), a reversible connector like Apple Lightning, and some daisy-chaining capabilities like Thunderbolt 2. The standard allows for up to 100W of power, although the highest powered adapters I’ve found are 60W. The Dell Thunderbolt 3 docking station has a non-standard option beyond this; when you’re connected to a recognized Dell device it will bump the power up to 130W just like the stock XPS 15 adapter.
But the catch is that USB-A power supplies are generally limited to 2.4A at 5V, with some exceptions for Qualcomm Quickcharge and Samsung Adaptive Fast Charging and the like (which can go to 9V or 12V on compatible devices). So most USB-A power meters will only show/handle 2.4A at 5V, or 12 watts. My smaller USB-C devices easily pull 15W whereas the XPS 15 should pull a lot more than that. Continue reading