[Nut-upsuser] Weekend Puzzle: computer posing as an UPS

[Greg Troxel]

Kelly Byrd <kbyrd at memcpy.com> writes:

> With USB-C ports and cables, there are a ton of profiles, I don't know what
> the new Pi's support, but likely something like 3A @ 5V, 9V, or 12V over
> USB-C

Up to the RPI4, I was pretty sure there wasn't PD, just 5V and it drew
what it drew, and you hoped that the supply was big enough.

It seems the RPI5 will use PD if given a capable supply.  Looks like 5V
5A, and it won't negotitate higher voltages.   There's an official
supply that does PD

  https://www.newark.com/raspberry-pi/sc1153/power-supply-usb-c-5-1v-5a-white/dp/82AK3955

and the output spec is

  5A at 5.1V, 3A at 9V, 2.25A at 12V, 1.8A at 15V

  looks like a TUV seal



I find Jim's way of using this interesting, but my approach is totally
different.  First, when I'm using a Pi, it's because I want a low power
computer that I can leave on all the time, or can place in a different
physical location I don't particularly want to do things on a Pi instead
of a desktop.  And then I want it to be reliable.

That leads me to plug a power supply into a UPS, or to use POE (from a
POE switch which is plugged into a UPS).  For RPI3, I found a POE
ejector that splits the POE ethernet cable into ethernet only and a
micro USB.