With Edison-style bulbs, anyway, the orientation they're mounted in makes a huge amount of difference. They're last a lot longer if they're oriented upright (base down) than in any other orientation because it reduces the heat buildup in the power supply.
If there was a "DC" light socket in the house we could have LEDs outlasting owners, and for cheap. Nearly all the expense of LED bulbs is the power supply. Everything else is dirt cheap. A single home DC power supply with ~200W of output could light an entire house, flicker free.
What's even more frustrating is I think we could fix it. A national regulation for DC light sockets would fix it. Mandate a voltage, shape, and max amperage and BAM, you'll get 1000 different manufactures making standard compliant bulbs and home power supplies that will last an eternity.
The lights are all basically cut 12v light strips inside of old light fixtures with a custom controller that also terminates PoE. The 48 volts that most PoE standards specify is more than enough to push power down the line for < 100 meter runs.
The advantage of PoE here is that anything under 50 volts is considered low voltage and does not need to follow the same rules as normal house wiring. I did not like that everything is hinging upon a beefy PoE switch so I actually made it passive PoE instead by design.
USB-C PD is at a useful voltage & wattage level, and so is Ethernet POE. I wouldn't be surprised to see them start to be used for general power distribution in niche applications, like RV's and off-grid cabins.
I don't think we're going to ever get a bulb standard, though.
I think the way to change it is to replace sockets with hardwired LED fixtures. This is easy for something like a standalone ceiling light. It may be harder for other devices like ceiling fans that integrate a light bulb socket, but converting those devices to take DC power as in your proposal isn't easy either (most would just get discarded and replaced).
Doing it well is more expensive in the short-term than screw-in bulbs. A quick look on Amazon suggests integrated ceiling lights are about 10x the price of LED bulbs, though I suspect the longer service life pays for itself.
Absolutely, the incandescent light bulbs have that shape for a reason: the screw is small because there is nothing to put in it and it doesn't heat, the bulb is large to dissipate all the light and heat it generates. And the LED light bulbs have exactly opposite problems: almost all of the heat is generated near the screw while the bulb itself generates almost none and the light-emitter doesn't even need the bulb that large around of it. Oh, and the casing around the screw is plastic so the thermal conductivity is horrible. Honestly, it's a profoundly terrible form-factor which we're now stuck with.
I live in Japan, and instead of just a pair of wires coming out of the ceiling, there is a standardized "ceiling socket" [0] which can also support the weight of a lamp. This means that swapping out light fixtures is plug and play, so the standard LED lamp is something like this [1] where you have a nice big flat metal plate backing the hardware is mounted to for heat-sinking.
I don't own any LED bulbs at all - all our lamps are of this type so I wouldn't have anywhere to put one.
It was the same when I lived in Sweden - a standard ceiling light outlet (IIRC there is a EU standard for this now called DCL) so that replacing light fixtures was easy. Moving into an apartment, often they wouldn't even come with light fixtures, you'd bring your own.
[0] https://www.e-connect.jp/images/to_quickB.jpg
[1] https://www.irisplaza.co.jp/IMAGE/HK/PRODUCT/H246902.jpg
And since we need high voltage (at least 100V) to keep line losses very low and allow the use of thinner-gauge copper wiring, we need a switching power supply at every light fixture, so it really doesn't matter if it's AC or DC, since modern SMPS (switch-mode power supplies) work equally well with either.
Finally, on top of all that, LEDs are current-driven devices, and need a constant-current power supply. So the power supply must be very close to the diodes, or else fluctuations in supply voltage will have very negative effects.
That means it's totally fixable. You can install such a system in existing buildings right now, and it's not crazy expensive unless you want to run the wires inside the walls.
If we could shift cultural expectations around this, adding a LV system in new construction would not significantly increase the construction costs. It will start to be done if buyers start demanding it.
LEDs are like 15% efficient and power supplies are >95%. They just need to be separated slightly so the LEDs aren't heating the power supply. Most recessed LED lighting now has a separate junction box with the power supply.
I think the biggest problem is that many cheap power supplies cycle at lower frequencies that cause flickering which is perceptible subconsciously. A modern switchmode power supply might operate in the 50-500khz range which will not cause perceivable flickers.
You can fudge it with resisters like in an LED strip, but you lose efficiency and dimming quality.
That being said, I expect that power supplies with 48VDC input or so would be cheaper.
I think that non-bulb LED fixtures are relatively common. For example, a style exists where you cut a hole in the ceiling and friction-fit the LEDs with the power supply up in the attic (presumably with infinite convective airflow): https://www.lowes.com/pd/Utilitech-Canless-Color-Choice-Inte...
These power supplies aren't going to die from overheating because the power supply is nowhere near the heat-producing LEDs. And, it's not like $30 for your entire light fixture is going to break the bank.
How about power over ethernet?
It's true that the power supply versions are so poorly designed and inefficient that heat is a problem. Design and quality control effort could reduce heat generated by the entire assembly to a fraction of what the socket, fixture, and wiring can sink.
It's more common now to find bulbs that have no power supply at all. They're literally a rectifier made of LED's in series. If the bulb flashes at 2 * mains frequency, that's likely what you have. They die out quickly because the LED strings add up to a maximum voltage a bit over mains voltage, but that's RMS not peak. It's a natural outcome, as using enough LED's to accomodate peak voltage reduces light output by underdriving them, increases obvious flicker from dwell time below minimum voltage, and increases cost.
Hotwired LED strings are cheaper to design, source, assemble, bad parts fail fast more consistently with no effort wasted on quality control, and the market's so flooded and volatile that there's no room for consumer side quality awareness effective enough to make the negative outcomes matter. Power supplies in these bulbs are going away. Ubiquitous 2 * mains frequency strobing, short-lived, hotwired LED bulbs is where the home LED lighting market is taking us.
This is a great idea and I would love it if you would post a Youtube how-to video. It might encourage a bunch of hobbyists to do something useful with those dead bulbs.
I've had a number of LED's fail after only a year or two, in fact more quickly than the average incandescent bulb. Seems like it defeats the whole purpose of "upgrading" and in fact may be more of a downgrade.
LEDs are super cheap. I bought few hundred pre-covid for $3.
I have the exact opposite experience, virtually every single light bulb I have torn down - one LED (all in series) has a black dot, if I shorten it - it will 'work' again. The bulbs I have seen tend to drive the LEDs so hard that some of the latter fail, power supplies might have huge ripple but generally don't fail catastrophically.
Edit: now thinking, it can be a US thing, with the voltage being ~120. Lower AC voltages means worse efficiency for the power supply (and all of them tend to be universal, unless totally cheapen out on the primary capacitor [250V] for the US market). Generally speaking low AC voltages have mostly disadvantages.
I have had lamps that lived long enough to see LED failures (the "black dot of death") but that's not the most usual failure mode that I've personally encountered.
I've been considering following in the footsteps of Big Clive and modifying new LED bulbs to stop them from overdriving the LEDs, but my interest in doing that hasn't yet overcome my inherent laziness.
If the bulb dies but you notice that all of the elements are still just barely on (like a dim spot of light in the middle of each one) then that's a good indication that you have a dead LED.
This is also the same industry and the same players that were perfectly fine with agreeing to not improve incandescent light past 1000 lifetime hours, illegally. I have no doubt that there is a tacit agreement not to make good lighting, as that would extremely disrupt the industry.
Otherwise, for probably at least 40 or so bulbs swapped for LEDs over the years, I've experienced maybe 4 or 5 failures. The vast majority of my bulbs have been Feit and GE. I never buy smart bulbs. My best experiences have usually been to just buy LED fixtures though, I replaced a lot of my flush mount ceiling fixtures and ceiling fans for ones with integrated LEDs and have not had a single failure so far after a few years, knock on wood.
I had some problems with my old dimmer switches, but upgrading dimmers to newer ones which advertised good LED dimming and ensuring I had bulbs which stated dimming compatibility it eliminated my noise and flicker issues. There's a recent standard out there, NEMA SSL 7A, which seeks to ensure good compatibility. I set my dimmers to this SSL 7A mode and I've had no problems since.
https://www.energystar.gov/sites/default/files/asset/documen...
They're all in freestanding floor lamps installed in a horizontal orientation, which might have something to do with it. That seems like it'd dissipate heat a lot better than e.g. a pot light housing in the ceiling.
They produce great light at the temperature you want and I’ve yet to have one fail after nearly 10 years using them.
Not cheap, but given I’ve never had to replace one maybe in the end they are
* bulbs with the UK-standard bayonet fitting in light sockets that are suspended from cables from the ceiling with lampshades -- these I don't think I've ever had fail on me yet
* 4.6W bulbs with a GU10 fitting in recessed spotlights -- these fail on me more frequently (perhaps every few years to every five years)
My assumption is that this is all down to the spotlight-fitting bulbs being in a confined space and getting a lot hotter. I use Philips bulbs in both cases.
- Older LEDs house bulbs were much worse than newer ones; far more prone to failure from "things". I had many of them fail after only a few months because our power was "flickery" and their power supplies could not handle it. That's _far_ less common now.
- The power supply / controller circuitry is not a fan of heat. Don't mount them upside down (so the heat floats up to the circuit) and never mount them in a recessed mount. The heat buildup will destroy them a lot quicker. That being said, this advice can be ignored is you're paying attention... mounts that have a way to heat to escape; bulbs that are designed to go in upside-down mounts (maybe?), etc.
- While you certainly don't want to always buy the most expensive bulb, you also don't want to buy the cheap ones. They are far more likely to be made from poor, failure prone components.
It’s not my fixtures’ problem.
It’s these crappy bulbs.
You don't go buy offroad vehicle, then complain it doesn't drive as comfortably on the highway and say it's an objectively worse vehicle. It was designed for a different goal than the 4 door sedan you're comparing it to. It does better at that goal, and worse at others. And, over time, offroad vehicles have gotten better on highways; they'll just never be as good.
The way most people use lighting goes far beyond whatever the manufacturers want to foist.
I don't know if there are any regulations around the 10-year claim, but if there are then I'd expect that it's either an average or something like a one-standard-deviation threshold, like 68% last past that but 32% don't.
"Guaranteed 10 years" doesn't actually say anything about expected lifetime at all, just that they'll do a warranty replacement if it fails sooner.
Personally I'd want a durability guarantee to be more like two standard deviations, on top of replacement in case of early failure.
A lot of this topic smells like typical geek snobbery. They're lights, folks. Cheap consumer products have always been cheap. Halogen bulbs suck too.
