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Comment by andix | Hacker News Reader

The biggest problem of LED bulbs is usually heat. The design is just not suitable for LED, it would be great if we get a new standard.

First thing is voltage, 120/230V is not suitable for LEDs, if lamps would have an external 12V or 3V power supply a few centimetres away from the LED, this would be great.

The second thing is, that lamps need some kind of (passive!) cooling solution, to remove the heat from the chip. A lot of lamps are more or less closed and heat up as a whole. This is really bad for all the electronics, and probably the main reason why LEDs fail early.

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Aren't filament bulbs the next evolution for both heat and power supply? The filament design puts the heat generation away from the electronics, and the electronics themselves are simpler because each filament can run off line voltage (or something along those lines). But they have more of a flicker problem IIUC.

The nice thing about newer filament bulbs is you can get 1600 lumen bulbs that are rated for enclosed fixtures now.

Yah, filament bulbs are the future of LEDs they solve basically all the existing problems of LEDs - heat, point-source lights, directionality, driver-size. And they are cheaper.

Is this satire, or am I missing something?

It does seem that the filament bulbs check a lot of boxes. The driver is so small it fits in the socket itself. If they can put 1600 lumens in an enclosed fixture, it does suggest they do better with heat. My impression from buying a box is that these are a next generation bulb design, not quite holy grail but a significant step. No more buying bulbs where the bottom half the globe is plastic housing a bunch of driver electronics.

I believe they are referring to LED filament bulbs, which are designed to look like traditional filaments but have the benefit of separating the LEDs from the electronics.

More here: https://en.wikipedia.org/wiki/LED_filament

???? I'm not sure what you find to be satire?

Have you used these LED filament bulbs? They are very good, the quality of the light is much better than the older style LED bulbs.

Without some kind of driver, the light flickers strongly at 120Hz. For sensitive people, the effect is extremely unpleasant.

One can get perfectly nice drivers and perfectly nice LEDs for less than $25 all in. Sure, many people prefer paying less for a screw-base lamp, but the result is not as good.

LED filament bulbs do indeed use a driver circuit. Some use a voltage above mains [1] while others drive the LED chain around mains voltage but in a smoother regulated way [2].

Sometimes there's just a basic dropper cap circuit, though. Those flicker but not too badly. The LED design in these is different than in a discrete LED, with the phosphor being quite thick and having a distinct slow fade/afterglow when switched off. I think in this case they basically use the phosphor to smooth out flickering instead of electronics.

[1] https://youtu.be/t3HpPikRDeY?t=279

[2] https://youtu.be/nMc6mjE9Y1s?t=447

I assume GP interpreted "filament bulb" as "incandescent filament bulb."

Which filament bulbs are you referring to? I was under the impression that filament was what we had before led bulbs.

LED filament[0], not tungsten filament.

[0] https://en.wikipedia.org/wiki/LED_filament

The efficiency difference in a power supply running off 120V or 12V is not significant. The power supply is a negligible portion of heat output. They would last longer if separate though. Slim recessed LED fixtures have their power supply in a separate box.

I.e. https://www.ledsupply.com/led-bulbs/slim-recessed-led-light (arbitrarily chosen, not an endorsement)

120/230V is not suitable for LEDs

It is with many in series, which is how the vast majority of lamps are made today. This lowers the current and reduces resistive losses.

I thought most household bulbs chopped it down to something like 30-40V.

Some lower spec lighting devices might take 120V and run LEDs in both series and parallel, but as LEDs fail, the rest get more current, leading to more failure… positive feedback loops for the win!

the parallel chains of serial LEDs are balanced during production so they all consume the same current and if any LED in a serial chain fails, they all stop working, simply eliminating that chain from the circuit. Of course in reality it's not that simple.

It’s not really very good to use them like that though - without a huge cap you’ll get pretty prominent flicker - I expect it’s probably just cheaper to stick in a cheap SMPS at that point if that’s something you care about.

"First thing is voltage, 120/230V is not suitable for LEDs"

Perfectly-fine if you put them in a series chain. In fact you reduce power losses at higher operating voltages.

USB LED slot would be great.

Tight enough to hold light bulbs, thoroughly time tested.

USB power adaptors are super cheap and durable and the existing designs may be used.

How realistic is whole-home Thunderbolt for lighting and smaller appliances?

Whole-house 12/24VDC power wiring has been a thing for at least 50 years, specifically intended for lighting. It's never proven widely popular, but it's certainly a realistic option. Probably more so in new construction than retrofitting into existing buildings, though.

Whole-home PoE for lighting might be another interesting approach!

In either case, you'd need a very beefy DC power supply somewhere to get enough current, or individual power supplies scattered inside walls, etc. which sounds like a maintenance nightmare.

Or keep the voltage high and step down with a buck converter in each socket as needed and negotiated with the device: there's a good argument to use ~300VDC as a future home electrics design. High-power devices (water heaters etc) will work better and more efficiently with DC, and low-power devices can deal with 48VDC with a lightweight step-down converter (5A buck converters are tiny)

From a purely technical standpoint, I agree completely. However, given the debacle around USB-C cables & PD, I'd be very worried about a world where I have to trust devices to properly handle such high voltages.

How safe is working with 300VDC?

Half-way there to 600 VDC traction power!

The LED strip behind my TV is powered by the USB port on my TV. Most longer strips (5m-20m) use one of a small number of form factor strips and 12V or 24V supply. There are also quite a few USB powered lamps, but a bulb form factor would be interesting.

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