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What happens when you connect two laptops through a USB-C port, provided both are able to charge through it?

Is that intended to be used like that? Can I transfer some juice from laptop A to laptop B?

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  • No, it won't work.
    – user931000
    Apr 8, 2019 at 17:07
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    @GabrielaGarcia Why not? Laptops are able to provide power via USB. Laptops are (by assumption) able to charge via USB. I've seen questions about someone accidentally charging their laptop from phone's battery, why wouldn't it work with 2 laptops?
    – gronostaj
    Apr 8, 2019 at 17:09
  • Some Dell laptops have "Powershare" so it's not beyond the wit of other manufacturers to have similar technologies. Basically if you can find two laptops willing to share power in a compatible fashion then the answer is "probably maybe."
    – Mokubai
    Apr 8, 2019 at 17:11
  • Because they can identify what's connected and behave accordingly. In an Android phone you can select the option to "charge only" so it doesn't care.
    – user931000
    Apr 8, 2019 at 17:12
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    It depends on what the laptops support through this connection, as some of the other comments allude. However, the more relevant question we need to ask you is "Have you tried this, and what happened?" Because it depends on what the laptops support, in order for us to provide you with a good answer you'll have to give us more information, but really, all you have to do is connect the computers. If you're wondering if anything will break: that's not very likely. Apr 8, 2019 at 17:37

1 Answer 1

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The depends entirely on the capabilities programmed in to the USB controllers of the laptops. Or, at least programmed in to one of them.

First, the laptops have to be able to charge themselves from USB-C, which is pretty normal.

Second, one of the laptops will have to support charging a different device over USB-C.

Many laptops support this, but they only send a relatively small charge out over the USB ports rather than the much higher current the power supply uses to charge the laptops themselves.

At very least, you can use a normal USB-3 to USB-C connector (like most Android phones have) to connect the laptop you need to charge to the charge-indicated port on the other laptop.

It typically will NOT be necessary to have male-to-male USB-C cables to do this.

HOWEVER, as noted, unless one of the laptops explicitly supports charging another laptop, it is very likely you will NOT be able to send enough energy to do anything but SLOWLY charge the laptop, and you will NOT generate enough energy to run the laptop from the USB of the other laptop.

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  • This will not work. Laptops need 20V when charging over USB-C. This voltage is negotatiated via PD (power delivery) protocol. I don't think any laptop can output 20V via USB-C.
    – mitjap
    Feb 21 at 0:12
  • It is theoretically possible, which is all my answer promises. Further, you begin saying "this will not work" and then end with "I don't think any laptop...". You don't have knowledge that changes the accuracy of my answer, yet you claim at the beginning it is wrong, and then everything you say after does not disagree with what I say. It is likely this is not currently possible, but even that is only a current state of things, and is also covered by my answer. Future systems may indeed support this, and they could use current tech to do this. Feb 21 at 2:56

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