Hi, all. I’ve been experimenting with different USB-PD sources (wall chargers, battery banks, etc.) and I’ve encountered an issue with devices that supply at the 15 V level. According to my USB-C power analyzer, the laptop is only drawing ~0.2 A from any PD source when it negotiates 15 V mode.
20 V mode seems to be operating fine; I’ve tested it with the Framework 60 W adapter, as well as a 30 W and 45 W adapter.
I’ve tested this with an Anker PowerCore Slim 10000 PD, as well as a PD source development board. With the dev board, I can force it to only enumerate as a 15 V max device or a 20 V max device depending on what input voltage I feed it. When it enumerates as a 20 V device, the laptop happily draws 2 A from it. But when it enumerates as a 15 V device, it only draws ~0.2 A from it. The Anker power bank only supports 15 V, and the laptop always draws ~0.2 A from it (except for the times when the laptop tries to charge it, but replugging it a few times will get it into the correct charging direction).
I can’t completely rule out the USB-C tester causing issues, but I can say that I did try connecting the Anker power bank directly to the laptop, and I observed the battery percentage going down despite the LED indicating charging. Thus, I’m pretty sure the same thing is happening without the tester in-line.
I’m running Arch Linux on my laptop, still on the factory BIOS 3.02. I’d love to test the beta BIOS, but I’m still waiting for there to be a non-Windows method for updating. If there is any way of seeing what the laptop thinks is happening USB-PD wise, that would be great to know.
Edit: I noticed this thread: Charging from a 30 watt USB-PD charger not working - #5 by Daniel_Brotherston which might be the same issue. The adapter shown in that post is a 15 V max, and the symptoms reported are similar.