Fun applications of PoE in homelab?

Looking at the amount of PoE splitters and how much people hate having too many power bricks, I was wondering of anybody is doing something unconventional with PoE at their homelab?

If you look at the PoE table at Wikipedia, you’ll see that apart from the common 802.3af (~13W), 802.3at (25.50W), there is the beefier 802.3bt with 51W and 71.3W depending on the type. I was wondering if anybody has stories of playing with the higher power types?

The list of bookmarks

… but given how many splitters there are:

  • PoE to USB-C (data+power) - guess it’d be cool for a dumb Home Assistant tablet - everything connected with 1 cable, but it’s easier to just use regular USB-C and WiFi :P Could be also used for a wifi-less weird phone server. Can also just charge your phone
  • PoE to Eth+12V - limitless possibilities. There’s a guy on reddit that connected a PoE to Eth+12V splitter to power his ISP modem. The PicoPSU also takes a 12V DC plug, so you can go PoE -> PoE to 12V+Eth splitter ->PicoPsu -> some low power computer -> burn down your house
  • Did some electrical engineer finally make a PoE solution for having so many power bricks when somebody has a SFF/TinyMiniMicro cluster? Those things are big.
antlion ,

I wish there was good PoE hardware. I wish I had it for powered blinds, doorbell (real chimes), and even can lights which are now so poplar.

litchralee , (edited )

Similar to your modem case, the fibre ONT on the side of my house is now PoE powered, because it would otherwise need two pairs from the CAT6 cable to provide 12v to itself, from a backup battery supply inside the house. Replacing that supply with PoE, this allowed me to centralize my network stack’s power source, so that a single UPS in my networking closet can power that ONT. It also reflects the reality that if my PoE switch goes down, my network is hosed anyway. There was also the issue that with only two remaining pairs, it would be impossible to realize 1 Gbps on the CAT6.

I also have PoE to the RPi1 units which attach to my TVs. These serve as set-top boxes with interactivity with CEC via the TV’s HDMI port, and are PoE because I insist on all my devices being wired rather than on WiFi, so might as well provide power as well. These use a microUSB PoE splitter, because 1) the RPi PoE hats mean I can’t fit into standard RPi cases, and 2) the PoE hat runs very hot and makes a high frequency squeal, which was unacceptable in this application.

Power cycling via SNMP on the switch is another nice benefit to having stuff PoE powered. In fact, I have one more application which depends on this behavior. I have a blade server which sits in my garage, that would otherwise consume a lot of standby power when I don’t need it. To fix that, a 240vac relay with 12vdc control coil sits ahead of it, so activating the relay turns on the blade server. That relay is powered by PoE, commanded by the switch, so whenever I want the blade server, it’s only an SNMP command away. iDRAC then communicates over the network using that same CAT6 that’s powering the relay, again recognizing the dependency that if PoE fails, the blade server is down anyway.

I’m only using 802.3at power levels right now, as that’s all my switch can do. If I ever acquire an 802.3bt switch, I might consider PoE lighting or PoE phone chargers, or silly things like that. There’s a lot that can be done with 60ish Watts. Note that the efficiency of PoE switches tend to be abysmal when lightly loaded.

Shadow ,
@Shadow@lemmy.ca avatar

Other than aps, I use several of these in places I don’t have space for a real switch (like behind my tv).

shop.poetexas.com/products/gbt-4-iw

Available on Amazon

unsaid0415 OP ,

My short unexciting story of replacing 2 power bricks with PoE:

I recently bought a D-Link DGS-1210-10P rev. B1 switch from ~2014 for $50. It has an 76W PoE power budget and supports up to PoE 802.3at (~25W).

(On the switch, OpenWrt is supported from rev. F1 - don’t be stupid like me with the rev. B1)

I had some PoE-compliant devices in my homelab that I was powering with ordinary power bricks, but now that I got my switch, that had to change.

In total I was able to remove two power bricks:

  • My MikroTik RB5009 UG+S has a 802.3af PoE-in on eth1, so I removed its power brick and powered it with PoE instead
  • My UniFi AP 6 Lite supports 802.3af PoE-in, so I removed the unifi poe injector that I had and powered it directly from the switch

My homelab is rather small, so the only two remaining devices which I could swap are:

  • RPI 4 with 2 SSDs - there are official PoE HATs, but you can also buy a shady PoE to USB-C + Ethernet splitter too - aliexpress.com/item/1005005764965215.html
  • ISP router changed into bridge mode, so it works as a modem only - you can also use a PoE splitter to power it, like this guy (bing cached version of reddit post). My ISP’s one uses a 12V 2.5A power brick, while the splitters 802.3at splitters are just 12V 2A, so I’ll probably won’t do it
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