I've read in multiple locations and have just confirmed through my own testing that Dell systems that support charging via USB-C limit themselves to drawing 65W from non-Dell power sources, even when the power source can provide more wattage and the system would benefit from more power. When I connect my Latitude 7480 to my Dell WD15 dock, the "Battery information" section of the BIOS identifies it as a 90W power source. When I connect that same system to my Nekteck 90W USB-C charger, which is fully USB PD compliant and certified by both USB-IF and UL, my Latitude 7480 identifies it as a 65W power source -- even though multiple Lenovo systems I have correctly identify that charger as a 90W source. Granted, the Latitude 7480 is only designed for a 65W power source anyway (although I believe it can take advantage of 90W for faster battery charging under heavy load if a 90W source is available), but then there are systems like the XPS 15 that are designed for a 130W power source. Those systems also limit themselves to 65W from third-party USB-C power sources, even though they'll draw 130W from the Dell 130W USB-C charger or Dell docks that are designed to supply up to 130W.
The 65W cap on third-party power sources is a frustrating and seemingly arbitrary restriction, and is especially inconvenient with systems like the XPS 15 that are designed for high-wattage power sources. I realize that using even a 90W power source with an XPS 15 might result in slower battery charging and/or performance throttling, but I might be fine with that on the road. But if I have a 90W power source available and the system refuses to draw more than 65W, that makes the power deficit and therefore the side effects significantly worse. Please stop limiting your systems this way.
jphughan, I have a Precision 7530, and can confirm this seems to be the behaviour.
I purchased a 90w non-Dell usb-c charger and it wouldn't charge at 90w.
However, I have also purchased what seems to be a genuine 90w Dell charger and it still didn't detect 90w.
@JimiScott interesting data point. The 7530 is quite new, AND it’s designed to be able to accept its full 180W over a dual USB-C connection so that docks like the Dell WD19DC can fully power it. So I would have expected it would support Dell’s own 90W and 130W USB-C chargers. But maybe not. I remember people with the XPS 15 9550 and 9560 finding that after Dell later released the 130W USB-C charger later (for the XPS 15 9575 2-in-1), it wouldn’t work at 130W with those older models, even though those models DID accept 130W over USB-C through certain Dell docks. Disappointing to say the least.
Wow this is so frustrating. What a bad move by Dell. Even Apple who limits everything doesn't have this kind of restriction. I hope Dell will change this with a firmware update. At least make them accept up to 100W, since that's the maximum for USB-C! Charging at 65W on a Dell XPS i7 Geforce gpu is like not charging at all.
I am seeing the same behavior on my precision 5530 (based on XPS so not surprising).
130W charging through the dell dock, but limited to 65W through any other usb-c charger I have tried and I know they are capable of 100W as they do it on other devices.
Pretty disappointing to see dell limiting the port with non dell hardware for no apparent reason other than to sell dell accessories.
It seems that this may be changing, somewhat. I'm seeing reports that the XPS 15 9500 and XPS 17 9700, both released in 2020, will allow up to 90W from third party USB-C power sources. This finding was observed when using a 100W USB-C power source with a system designed for a 130W power source. The XPS 15 9500 is only designed for a 90W source when equipped without an NVIDIA GPU. XPS 15 configurations with an NVIDIA GPU, and all XPS 17 configurations, come with 130W power supplies. So it seems Dell still hasn't completely lifted the restriction on third party charging, since otherwise these systems should be able to charge from third party sources up to the 100W max of the USB PD standard. But 90W is better than 65W, I guess.
Here is a link to a thread where this was discussed in greater detail.
I am also unable to charge at full power with 3rd party chargers over USB C. The RavPower 90w charger negotiates to 90w on my XPS 15 9500, but only 65w on my Precision 5540. It would be great if Dell would issue a BIOS update to negotiate more common USB-PD configurations in these machines.
What is the situation with Dell Latitude 15 5510? It supports 90W charging. I was planning to buy it and charge it with a third party compact travel USB-C adapter. Also was planning to buy a Dell monitor that charges it via USB-C. Which will work? I guess the Dell monitor should definitely work? But I won't buy it if third party compact chargers/adapters don't work. This is something Dell needs to fix/officially support before we buy their laptops. There is a reason the USB-C Power Delivery spec was created - it was to avoid proprietary expensive chargers.