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Comment by Someone1234 | Hacker News Reader

Slight tangent but "in-building DC" exists, and is rapidly gaining popularity but not via the medium many assumed: Power Over Ethernet.

You can buy PoE LED light fixtures now, which are both powered and controlled over ethernet. You buy a single PoE switch, run some low voltage Cat6, and you can power an entire floor's worth of lighting.

EEPoE (Energy Efficient PoE) offers more efficient PoE too which claims up to 94% efficiency.

Definitely a space to watch. Particularly as the cost savings of running low voltage Ethernet cable compared to high voltage electrical cable (110v) are substantial.

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EEPoE is new to me:

Microsemi's exclusive EEPoE technology cuts the power losses on Ethernet cables by 50%, through the utilization of all the copper available on cable when a Microsemi EEPoE PSE IC or Midspan is used. It is 100% compatible with IEEE802.3at, and the savings work with ANY IEEE 802.3at Type 2, Type 1 or IEEE 802.3af compliant PD. In practice, devices that consume 25.5W would consume less than 27.75W, instead of the worst case 30W when a non-EEPoE PSE is employed.

So they use all 8 wires for power instead of just 4 to halve the power loss on the wire. For the worst case device that makes the 20% loss be a 10% loss.

Does that mean you cannot use it for any regular Ethernet data signaling at the same time, or is the signal overloaded on the DC?

You can. I used to work for an ISP and every WiFi access point I installed had Ethernet+DC over the same cat6 cable. Still got 100 megabit speeds

Definitely watching. I once was in the LED industry when it was still hot. The company was called Zega.

They tried every random thing, including putting a small real ARM server on the bloody thing to do remote control. It was back then when I first stumbled on Espressif people and Teo. They got lightyears ahead of us with all-in-one SoC.

you can power an entire floor's worth of lighting

? Must be either very low current lighting or that's some pretty beefy Cat6. I think the average Cat6 cable is only 24 gauge and that won't carry a lot of current very far.

Star topology

Isn't this like saying you could light the world if you had a big enough switch and unlimited cable?

Where did you get that? GP is talking about lighting a floor in a building.

He's talking about running a separate cable for each and every bulb. It's a wasteful solution compared to running all of the lights off of a single circuit (or limited number of circuits) like a normal building.

No I wasn't. PoE+ can support half a dozen LED panels off of a single Cat6 run.

PoE+ will deliver 30W to the far end of up to 100M network cabling. Given that those cables radiate out to endpoint devices from a central point, rather than powering multiple devices in a ring/loop topology, the potential to power lots of devices over a wide area is huge.

Biggest problem tends to be accommodating the central power delivery device. Those big PoE switches run hot and loud.

TIL about PoE lighting.

I always imagined homes would migrate to 12VDC and converge electronics with RVs.

A small DC-input PoE switch in your RV might be the next logical evolution :)

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