USB-C extensions are not allowed for a reason
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There is a reason for USB-C extensions not to be part of the standard. They can be bothersome in the best case and dangerous in the worst. The cable tester f...

There is a reason for USB-C extensions not to be part of the standard. They can be bothersome in the best case and dangerous in the worst.

  • WraithGear@lemmy.worldEnglish
    305·
    15 days ago

    So a standard cable needs to be chipped to show its rating to the device, its not that the device can pull what it wants or can get, but the cable itself tells it what it can supply. Extension cables can’t do that, because it doesn’t know what it’s plugged into, and that would be if they even bothered to put a chip in. They instead piggy back off the chip for the main cable. The problem comes when you you have a 240 watt cable hooked up to a cheap 120 watt cable, with the device being told it can push 240, and starts to super heat the extension cable

    • Mr_Blott@feddit.ukEnglish
      856·
      14 days ago

      Brilliant thanks

      5 sentences that inexplicably need a 9 minute video to say

      Fuck YouTube

    • Anivia@feddit.orgEnglish
      101·
      14 days ago

      Correct, except for your example. Firstly, 120 watt USB c cables don’t exist, only 60w, 100w, 140w and 240w. And only plugging in a 100w or higher cable into a 60w extension would be dangerous, since it would allow drawing 5 amps on a cable over an extension only designed for 3 amps. However, as soon as your extension is rated for 100w it is completely safe to use with any USB c cable, even those rated for 240w, as those only operate at a higher voltage but still only allow 5 amps max.

      I have also never seen an USB C extension cable rated for less than 100w, so this is kind of a moot point. If 60w usb c extensions exist somewhere, they would indeed be dangerous, but I have never come across one

    • Obinice@lemmy.worldEnglish
      42·
      14 days ago

      Interesting, I’d never trust any USB cable to push anywhere near 100 watts anyway haha good god, the most I ever do is maybe 20w at 5v.

      I’ll keep that in mind when buying cables in the future though this is very useful info!

      • fine_sandy_bottom@lemmy.federate.ccEnglish
        9·
        14 days ago

        As a point of reference, Lenovo Thinkpad’s have something of a cult following for their reliability and versatility.

        My T490s has a USB-C power supply which provides 45w (20v at 2.25a).

        The thing is, when docked it’s not only pulling power through that cable, but also network, USB devices, and providing video for 2x monitors in 1920x1080. It’s kind of astonishing to me how much can be crammed in to one little connector. That said, it’s frustrating trying to find a usb cable that works reliably, because as you’d imagine not all USB-C cables support the same specs.

      • GreyEyedGhost@lemmy.caEnglish
        7·
        14 days ago

        If you buy a Steam Deck, or the Lenovo laptop I have for work, the only charging options you have are USB C. Their standard chargers put out at least 60 45 W, and they aren’t particularly special. In fact, I’m pretty sure 20 W at 5 V won’t be enough to supply these while in use, so you will either be using battery with long charge times in between, using them with battery-assisted power for longer use times until you hit those long charge times, or using the 60 45 W or more at whatever voltage the chargers provide.

      • iopq@lemmy.worldEnglish
        5·
        14 days ago

        My laptop can do 240W over USB-C, I’m just waiting for a charger that can do it with a modular cable