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0 pointsZak3y ago0 comments

Trying to cram all the infrastructure for an LED lamp into the shape of a light bulb is a bad idea, even if the input power is DC. Good designs for LED lighting have larger surface areas for heat dissipation and some physical/thermal separation between the LEDs and the power supply. A quality power supply does not produce flicker. As other comments have noted, dimming, or even predictable output requires some sort of power regulation even with DC input.

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.

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10 comments · 3 top-level

Joker_vD3y ago· 5 in thread

> Trying to cram all the infrastructure for an LED lamp into the shape of a light bulb is a bad idea, even if the input power is DC.

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.

dredmorbius3y ago

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).

amluto3y ago

I sure hope 12V doesn’t happen. 12V is absurdly low for lighting and needs extremely thick wires to get decent efficiency.

24V is okay. 48V would be nicer for indoor use.

4 more replies

Smoosh3y ago

There are also these type of "ceramic substrate" bulbs which claim to give longer life. I suspect other compromises in the construction may negate that.

https://www.sansiled.com/blogs/learn/what-are-the-benefits-o...

ZakOP3y ago

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).

Joker_vD3y ago

Well, one of the main sales point of the LED bulbs was compatibility with existing E14/E27/etc sockets: no need to change the wiring, or the fixtures, just buy a new, better light bulb and screw it right in! It will also serve longer and be better for the environment, what's not to like? We'll even ban the sales of 100W and higher incandescent light bulbs to help you make the right choice!

That's also the pitch of the smart bulbs: a sane way would be to make a smart light switch but what if you can't do that (e.g., you rent the apartment)? So we'll shove the controller chip into a disposable light bulb, that's still perfectly fine for the environment.

By the way, I don't know how things turned out in your part of the world but over here, after the ban went into the force the manufacturers of incandescent lightbulb started selling 95W light bulbs 8D

petrocrat3y ago· 1 in thread

Probably going to sound crazy, but we could start running water pipes in front of the walls and under the ceilings and mounting the LED's directly on the pipes for cooling. Creativity, thinking wholistically... the entire contemporary western house design needs a rethink frankly, from DC circuits to electrification to modular, mass-produceable utility drop-in pods, all with an eye towards integrated systems design paired with scalable modularity.

wkat42423y ago

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.

kalleboo3y ago· 1 in thread

One of the problems is that in some countries like the US, ceiling lamps are hard-wired and not "user-replaceable", so people have to resort to using those stupid bulbs in their old fixtures.

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

yourusername3y ago

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.

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