this post was submitted on 13 Nov 2023
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I'm looking at clearing down some of the power bricks that are in my homelab along with plug requirements. There's 3 devices that run off of 12v, so the current idea is to buy something like this:

https://uk.ugreen.com/products/ugreen-nexode-200w-usb-c-gan-charger-6-port-desktop-charge

And then this: https://www.amazon.co.uk/gp/product/B0B9FDZX7P

With the aim of powering:

  • Beelink Mini-S12
  • Virgin Media Hub 3 (this is the worst power brick)
  • asus dsl-ax82u
  • Raspberry Pi 4 (no converter needed, but will eliminate a plug)

I'm aware this is a single point of failure, it will be plugged into a UPS. I'm just wondering on the viability of it all.

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[–] [email protected] 1 points 1 year ago

That’s not physically possible, negotiation is required for voltages over 5V. And the voltage may not be within the spec of the device. USB-PD provides higher voltages in order to push more power through a USB cable. Higher voltage means higher wattage for the same amps, meaning less power lost due to cable resistance. You can’t just push 5V 10A through a USB cable or it would melt, but you could push 20V 2.5A, for the same 50W total but with a non-melty cable. So the voltage may not be precise and is usually used to drive a buck converter at the other end to drop it down to a usable voltage again. All this requires expensive components and complex firmware.

What you’re probably looking for is a regular 12V DC power supply. There’s just no need for all the expensive USB-PD negotiation for your use case.

Plus, as others have said, USB-PD chargers will disconnect all devices whenever power requirements change. This can happen at any time even without the devices being unplugged-re-plugged, it happens whenever the power needs dictate a switch to a new USB-PD mode.