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I’m planning my first “proper” Raspberry Pi project.

I want the end result to be user friendly, and so should use only a single power source.

But internally I need to power several separate devices: the Raspberry Pi 4 itself, as well as two peripherals that have 12v dc barrel type power sources.

After much searching, I’ve not found much detailed information on best practices for powering Raspberry Pi plus peripherals, other than .

Is there any reason why I should not do the following, or is there a better approach?

  1. Power the project from the mains using a USB-C adapter.
  2. Connect to a USB-C hub.
  3. One port on the USB-C hub will power the Raspberry Pi.
  4. Two ports on the USB-C hub will each use a PD board to deliver 12vdc to the peripherals.

Is there anything I should be checking first to ensure this will work? And is this really a better approach than powering from the GPIO interface?

Thanks for any pointers.

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For one, you need a very good hub that can support a Raspi. Most won't deliver enough power. Also, the PD boards will drain a respective amount of power themselves (unfortunatelly, your link does not specify the max power output of these boards).

Depending on the power requirements of your sensor boards, I'd rather go the other way round and power everything with a 12V power supply and use a (good) car charger to power the Pi from 12V. You should probably have about a 30W power supply (delivering 2.5-3A at 12V).

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    USB C hubs should be enough to light a Pi; ideally each port can deliver 2.4 amps. While the same claim has been made by USB A phone chargers for years and most of them are not really capable of delivering enough instantaneous current, one hopes that C is an upgrade. I notice the hubs refer to them as "charging ports" though, which implies they might have the same problem. I believe there may also be an issue with the Pi 4 whereby it doesn't meet spec properly and hence the port may not respond properly -- not an issue with a dumb wall wart.
    – goldilocks ♦
    Nov 3, 2020 at 15:57
  • @goldilocks Yea, like the USB-CD-Drives we used a few years back, that were USB(1.0)-powered, and sold like this. No chance to get them working except by hardwiring the USB +5V line to the PC power supply directly.
    – PMF
    Nov 3, 2020 at 16:03
  • Thanks both!, this is really useful! Upon closer inspection, it seems that USB C won’t deliver my power needs, and that few hub ports are powered. I’m going to go with a good old 12v supply.
    – Andy Harvey
    Nov 10, 2020 at 20:26

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