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I would like to use the Dell 24 UltraSharp Monitor: U2415 to charge my laptop which has a USB 3.1 type C port.

The monitor does not have a USB 3.1 port itself but offers the following connectivity ports:

  • 2 HDMI(MHL) connector
  • 1 Mini DisplayPort
  • 1 DisplayPort (version 1.2)
  • 1 DisplayPort out (MST)
  • 5 USB 3.0 ports - Downstream (5 at the back, 1 with battery charging)
  • 1 USB 3.0 port - Upstream

Will I be able to charge my laptop through any of the monitor's ports (given that I use an adapater cable such as USB 3.1 to HDMI)?

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  • What happens when you try it (on the charging port)? You won't damage anything, and your laptop's battery status monitor will show you if it's charging or not. If it's receiving reduced current, it may charge when idle or sleeping, but slowly discharge while in use, depending on its load. Use a 3.1 lead, which should have lower impedance.
    – AFH
    Commented Dec 18, 2017 at 16:38
  • @AFH I don't have the monitor yet. Thinking of buying it
    – horen
    Commented Dec 18, 2017 at 16:41
  • A quick check says that 3.0 and 3.1 have similar power delivery specs, so my comment about the lower impedance cable probably isn't relevant, but as Ramhound says you can't use an HDMI converter cable. Maybe you could try another 3.0 device, such as another machine with a 3.0 port or an early USB3 charger.
    – AFH
    Commented Dec 18, 2017 at 16:53

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Will I be able to charge my laptop through any of the monitor's ports (given that I use an adapater cable such as USB 3.1 to HDMI)?

You cannot charge your laptop over HDMI/DisplayPort or USB 3.0 connection. As for the reason, if you use a converter, then you lose the pins that make it possible to charge your device over Type-C in the first place.

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Getting power from your display to your laptop is possible, though unlikely, given the ports you list. Even even less likely is this power to be enough to charge the laptop while you use it.

USB-B ports do not provide power. USB-A ports provide power but no more than 12 watts, that is assuming they meet the USB spec. There are devices on the market that violate the USB spec to provide more power than 12 watts through USB-A but if your laptop is going to take advantage of this then the cable to the laptop would also have to violate the USB spec, and do so in a way that matches this non-USB spec. Also, 12 watts is a maximum, the minimum allowed from USB-A is 4.5 watts.

DisplayPort and mini-DisplayPort provide power but this is less than 10 watts and is intended to provide power to attached cables or adapters, not to connected devices. The pins that provide power are not supposed to be wired to the other end of the cable.

HDMI ports provide power as well, and like DisplayPort, this is not supposed to be wired to the other end of the cable. MHL uses the HDMI ports and connectors and allows for power from the display to an attached device. MHL cables can use the HDMI connector on only one end, the other end will have to use some other MHL compliant connector. One such connector is USB-C. MHL devices connected with HDMI connectors are still limited to what power HDMI can safely handle, which is 7.5 watts. That is enough power for a Slingbox receiver, Chromecast device, or smart phone, but not enough to charge a laptop computer. Because not all MHL ports provide the maximum allowed power those tiny Chromecast and Slingbox devices that hang off HDMI/MHL ports always have a power input port separate from the HDMI/MHL connection.

In the unlikely event your laptop supports MHL on it's USB-C port then the only way to get power from the display, while getting video to the display, on one cable with the ports listed is with a MHL cable with HDMI on one end and USB-C on the other. That's unless this is some unusual display that allows for video on USB or something. There's plenty of cables out there with HDMI on one end and USB-C on the other, such cables will only provide power to your laptop if they are MHL cables and even then it will provide at most 7.5 watts.

You'd likely get more power from the display to your laptop with a common USB-A to USB-C cable plugged into the USB battery charger port on the display than you would with MHL. Using a USB-A to USB-C cable to charge your laptop means no video, again unless your display has some unusual features, or you are using some other cable between your computer and display.

Using the display's MHL or USB port to charge a laptop might come in handy if in dire need, and might be worth a few chuckles as a kind of party trick, but that's not something I'd recommend for daily use.

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