I am going to open source it. The goal was to be able to get all the SMD stuff available at JLPCB so you can just send it to be fabbed (with some thru-hole components you would just solder yourself) or I would also sell them at cost + 10%. My brother designed some 802.3at chips and was going to have him review my work first as I don't want to send out into the world a poorly design power system (there are enough of those things out there unfortunately).

If you're introducing electrical incompatibility, why on Earth would you try to preserve mechanical compatibility?

> but that’s problematic when the next owner tries to screw in a standard bulb - what happens when it sees 48V DC?

If by "standard" you mean a incandescent tungsten filament bulb, nothing at all.

For a true LED driver power supply, it would be constant current, so the tungsten filament would see 25mA (or whatever the constant current is set for) of DC, and nothing bad would happen (the filament also would not likely illuminate either).

Screwing in an LED bulb with integrated power supply, the external supply will still feed the constant current value, so what happens depends upon the design of the LED bulb's integrated power supply. If 25mA is enough to drive everything, the LED bulb might light up. If 25mA is not enough to drive everything, most likely nothing lights up.

>screw in a standard bulb - what happens when it sees 48V DC?

Either it lights up or not? I don't see a problem here.

But I'm not sure moving part of power supply elsewhere will help that much, it needs current driver electronics anyway.

The usual counterargument is: voltage drop can become a problem. Trying to use one big power supply and use DC as your only distribution mechanism probably isn't a good idea.

But choosing a DC system for part of the house can make a lot of sense.

For one residential new construction room, it can be practical to have one shared power supply rather than one per LED. Say you have a 12 V, 5 A DC power supply. Using a star wiring topology, this can serve 10 lights (at 500 mA) fine with 16 AWG.

Even 12V over 50ft+ will have noticeable voltage drop unless you have huge wires. 5v? Not even worth considering.

And switch mode power supplies are relatively inexpensive and quite efficient.

The wires would be thick asf

Not practical

Until I see someone defining a representative example and running the numbers, I'm skeptical of their DC vs AC commentary.

I say this, because I was guilty of this exact shortcut thinking (in another comment). But I paused and thought to myself "I should run the numbers before just repeating the usual voltage drop criticism".

So I compared scenarios and it depends a lot on the topology, lengths, costs, and situation (new vs renovation).

Sure, a whole house system doesn't typically make sense, but I don't think that's what people are really talking about. I think people are interested in hybrid systems; e.g. DC power supply for each room.

I don't know if you meant it, but the sentence about "any sophomore level electrical engineering student can solve this" can easily come across as dismissive. I also think it gives too much credit to sophomore students. :)

I would have more confidence in an electrician apprentice on this one. I think they'd have more practical experience when it comes to figuring out what are the right questions to ask.

I did EE in college and do a fair bit of hands on residential electrical work.

P.S. How many sophomore level engineering students learn to do a sensitivity analysis?

There are finned LED bulbs which can fit standard Edison Screw sockets, e.g.:

<https://www.designboom.com/technology/self-cooling-100-watt-...>

<https://i.pinimg.com/originals/b5/c2/c5/b5c2c5d69fb240a571ba...>

It's also helpful to recognise that existing lighting fixtures and lamps were designed around the constraints of incandescent bulbs. The first generation of LED bulbs and lamps largely conform to these. As LEDs mature, both fixtures and lamps which address the limitations and requirements of the technology (transformers, perhaps dedicated 12v circuits, heat dissipation for the transformer rather than lighting elements themselves, and better light-temperature and intensity regulation) should emerge.

We're presently in the somewhat-messy half-emerged state. Think horseless carriages, wireless, and the days of dual gas/electric lighting and lamping systems (yes, these existed, and yes, the failure modes were ... much as you might imagine).

I don't think we're exactly stuck with the old form factor. We can start phasing them out. Replacement of screw sockets with modern fixtures is well within the capabilities of the average DIYer (though perhaps some places it's illegal for anyone but a professional electrician to touch anything hardwired).

In a normal house you're not going to need that much light that you'll need water cooling.

Simple metal fins are more than sufficient along with a high efficiency power supply.

In the Netherlands we have just a pair of wires coming out of the ceiling but everyone replaces their own lamp fixtures anyway. Most people should be able to manage clamping or screwing down the brown or black wire to the L and the blue wire to N.

Low-voltage doesn't necessarily mean 12V. I think it's anything below about 50, although lighting systems currently marketed as "low voltage" are usually 12 or 24 volts.

The constant current thing is true, but that's not a terribly difficult problem.

That works OK because the transformer is relatively close to the lights. If it were a reasonably-large house, and the transformer were on the opposite side of the house, you'd have a problem with a noticeable voltage drop. All these ideas people are throwing out here involve a single whole-house power supply. If it were for 48VDC, it would probably be fine, but 12V would result in significant line losses.

The really cheap stuff actually doesn't even have a power supply! There's a breed of LEDs that takes straight AC and rectifies it using the LEDs themselves. By using a large number of tiny LEDs in series (typically in COB form), you can easily reach close to 110v or even 220v, and then you add a small current limiting controller in series that's dirt cheap compared to magnetics... These are super cheap, and appear bright, but they flicker at 120hz, which can be annoying when there's motion or if you're sensitive to it.

I'd say it's a very bad choice for a bedroom or living room light, but I have nothing against it for the outdoor lights, signage and a bunch of other applications where cost is king.

>Maybe this could be a prosumer retrofit thing, where the AC voltage gets converted to DC in the junction box, and then DC is sent down to the fixture.

The problem is that in 99.99% of homes outlets are on the same circuits as light fixtures, you would need to do some major rewiring.

You will see need to current drive the LEDs, DC alone won't help.

I used to do electrical installs in commercial buildings and this was starting to catch on, mainly because the the practice of running ethernet (including the 8P8C aka RJ45 connector, patch paneling, etc) is already established. This always felt very roundabout and requires expensive networking equipment just to run lights which I do not personally like because it will just cause confusion.