I'm trying to understand how USB-C charging works in practice. I have a laptop that officially supports 100W charging, and I'm using a 100W USB-C charger, but it rarely pulls more than about 60-65W during charging. I've tested with different chargers and ports, and this behavior remains consistent. The laptop charges fine but slower than I'd expect, and there are no error messages. I'm curious if this is normal for USB-C Power Delivery, whether laptops limit power based on thermal conditions, and if the USB-C cable could be silently limiting the power without any notifications. I'm really just looking for clarity on my expectations or if there's something I'm missing.
4 Answers
It's tough to say for sure without knowing your laptop's brand and model. Can you share that?
None of the Dell or Lenovo models in my office fully support the USB Power Delivery standard, although their chargers have USB-C connectors. A good tip is to check how your laptop's charger connects. If the USB cable plugs in, it usually supports PD; if it's hardwired, it might not.
The cable you're using needs to support 100W charging as well. Many cables don’t, which might limit the power.
Exactly! I'm focusing on whether the e-marker or 5A handshake is functioning properly next. A lot of cables might claim they're 100W-capable, but under heavy load, they might drop down to 3A, which could explain the 60-65W cap I'm seeing.
Yes, all of that can definitely happen. There are a lot of variables involved with USB-C charging.
Yeah, I hear you. There are just too many factors that could affect it, which makes troubleshooting a bit tricky.
You're right; I should've mentioned that! The charger I'm using is an Anker 747 (150W), and I have a 2m USB-C cable rated for 100W. My laptop is a Dell XPS 15. Just to clarify, PD negotiation does work, but it looks like the power caps at around 60-65W under load, not close to 100W. I'm wondering if that's due to the cable, the charger's logic, or the laptop's profile.