Charging a laptop though a USB-C power port with a low voltage/amperage

batterylaptoppower supplyusb

Let's say we have a new laptop with a USB-C port – like the new Macbook1 or the Chromebook pixel which, yes, are meant to be charged through these ports -, a good solar panel for smartphones (5V 3A for example2) and a USB-A to USB-C3 cable to connect the two. Would this setup (very slowly) charge the laptop battery theoretically? Or will the laptop simply ignore the power source, because the voltage/amperage isn't correct/as expected? Of course you can replace the solar panel with just an old fashioned smartphone charger, but I thought the solar charger example was a lot more interesting.

Notes

  1. https://support.apple.com/en-us/HT204360:

    Your MacBook will charge from USB-C power adapters not manufactured by Apple if they adhere to the USB Power Delivery specification.

  2. Random example of such a solar panel from China

  3. Random example of such a cable from Google

Best Answer

I’ve not tested the MacBook. The Dell XPS 13 I have in front of me right now appears not to even trickle charge on USB-C at 29W even when the laptop is turned off ... it wants 45W. I’m going to leave it overnight but I am not confident it will work at all.

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