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 10 months ago

never even considered that - I'd be curious to hear how you get on

[–] [email protected] 1 points 10 months ago (1 children)

Interesting, but mind you that some USB-C adapters may only be rated for 5V 3A or 12V 3A and will not be able to deliver the full rated 45/60/100W of power at lower voltages.

[–] [email protected] 1 points 10 months ago

12v 3a is 36w, which is what all the devices I've linked cap out at. Most of the devices have a power brick which puts out 12v at 2.5a.

[–] [email protected] 1 points 10 months ago

I use one from Amazon as you show, 12V and 9V. No problem, I use about 9 month.

[–] [email protected] 1 points 10 months ago (1 children)

I’ve found this particular use to be frustrating. USB-PD negotiates how much power each port provides when the device is plugged in, which in practice means whenever you plug or unplug something from the adapter, it cuts off power to every other port while it renegotiates and reallocates the power to each port. This will kill power to the router, miniPC, etc.

If everything is kept plugged in and powered on at all times together—including the Raspberry Pi and the miniPC—then I guess this is one way to eliminate power adapters.

[–] [email protected] 1 points 10 months ago (1 children)

Yeah just reading up on it. I'm wondering if there's a USB-C device which has zero negotiation time? At the worst case, I may just get a dedicated USB-C charger for the Router as that has the most obnoxiously large power brick.

[–] [email protected] 1 points 10 months 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.

[–] [email protected] 1 points 10 months ago

I bought 12v trigger board from AliExpress for different thing (medical device) since its own battery was 150€ and using usb-c pd brick was 1/5 of the price.

Works really well, no complaints from here. It takes 2A of current only so that might be limiting factor.

[–] [email protected] 1 points 10 months ago

At 12v you can draw only up to 1.5A.

Ugreen chargers will reboot ports to distribute power to all ports (so all devices will be rebooted)

[–] [email protected] 1 points 10 months ago (1 children)

I would step out of the USB / PC realm and look just at DC power supplies. Like this guitar DC/Barrel power source: https://www.amazon.com/Donner-Guitar-Supply-Isolated-Output/dp/B00WHLLDWO/

NOTE: I just google for "Multi DC power supply" and found that. Point being. I have zero experience with that power supply, but DC power has been around WAY long than USB and it is very well supported across many industries. When it comes to DC, you really only need to look at the Volts too, forget the Amps. I'd say only the Beelink needs to be considered in Watts everything else just V's.

[–] [email protected] 1 points 10 months ago (1 children)

I took a look around for high-ampage 12v DC power supplies. There's a few out there which do 12v at 12.5a and provide a DC jack splitter (https://www.amazon.co.uk/12V-12-5A-Power-Supply-Replacement/dp/B0BQJ4B8FT), but that's using a brick power supply.

The reason I'm keen to get rid of the power bricks is due to the space constraints I have. If I can replace 4 devices bulky power supplies with 4 USB plug ones (like this https://www.amazon.co.uk/gp/product/B08CDDSVN4) then I'll be happy.

If I had more space then I would absolutely go for something like this: https://www.amazon.co.uk/Surom-Universal-Regulated-Switching-Computer/dp/B072J97N8T and custom-do my cables.

[–] [email protected] 1 points 10 months ago

I did similar, but I got a DC UPS and it's running: 2 Odroids (like Raspberry pi), a wired router, and a 16 port switch. (edit: as seen here https://ibb.co/album/Jxrb06 )

TalentCell Mini UPS Uninterrupted... https://www.amazon.com/dp/B07WLD32RP?ref=ppx_pop_mob_ap_share

[–] [email protected] 1 points 10 months ago

Have you looked at Poe adaptors? You can get them that take in Poe, give out ethernet and 12v, the only concern may be current capabilities.

[–] [email protected] 1 points 10 months ago

Keep us posted op