Can you tell me if this repair is still working for you?  Just bought this same machine and it's having an identical issue. Sorry I updated the BIOS late last night, and then went to work all day today away from my computer. As of now the charge is reading at 130W again.  Thank you.
I have about a month old XPS 9510 that now says slow charger detected whenever using the Dell USB-c charger that came with it. I get a BIOS message on startup as well that the charger is insufficient size. Started about a week ago. This happens on all 3 USB-c ports and on BIOS v1.4 and v1.3.2. Tried all combination of unplugging and leaving unplugged for hours and no change. In the BIOS in reports the AC adapter as 5 watts when plugged in. Anyone else experience this? I guess the power adapter is just fried somehow?
XPS 9510 slow charger detected