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There's something off about LED bulbs

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Re: There's something off about LED bulbs

#721

Post by PaulDavisThe1st »

ghayes wrote: post #607
PaulDavisThe1st wrote: post #213

Earlier quoted context omitted.

> I actually am opposed to bans on traditional incandescent bulbs AFAIK, there are no simple bans on them [ EDIT: in the USA ]. What exists are energy performance standards, which these bulbs do not meet. If you want, you can say that this is nit-picking, and that of course that's a ban. But when we have energy performance standards for, say, cars, nobody says it is a ban on cars, just a effective end to the producti…

But if we said cars need to achieve over 1000mpg, then it would be effectively a ban on ICE, right?

In practice yes. However, someone might also just say "No more ICE" and that is semantically different. Sure, in the real world, no practical difference.

Re: There's something off about LED bulbs

#722

Post by t0bia_s »

fexl wrote: post #677
chongli wrote: post #465

Earlier quoted context omitted.

The big problem for me is, as a consumer, how do I know that brand X is producing quality bulbs that'll last a long time? The issue is that LED bulbs aren’t simple devices like incandescent bulbs. LED bulbs have an electronic power supply inside which drives the LEDs at a constant current. Power supply design is a major subfield of electronics engineering and there are all kinds of tradeoffs you can make to optimize…

I've noticed that LED bulb packages say they'll last several years, but so many of them die after just a year or so. I should start tracking this precisely, but I've just gotten the sense that they often die prematurely.

You have 2 year warranty. Return it. My dad did it so often that they refuse to sell him a new one in that shop. What an irony.

Re: There's something off about LED bulbs

#723

Post by verisimi »

tomatotomato37 wrote: post #150

I hate how many of these things aren't limits of the technology but rather the result of cost optimization and general apathy towards the customer. We know how to mass-produce quality LEDs to the point entire TVs are made of the things. We know how to mass-produce rectifiers pretty much ever since diodes existed. We know how to cool mass-produced objects in compact spaces. But because we apparently can't have nice th…

They are poor by design! You want repeat customers of course!

Re: There's something off about LED bulbs

#724

Post by marcosdumay »

Majromax wrote: post #712
marcosdumay wrote: post #626

Earlier quoted context omitted.

What numbers do you expect to see for flicker?

Ideally? Something like RMS and peak-to-peak amplitudes below 120Hz and below 1kHz, when fed with good AC power. The former would be potentially noticeable in peripheral vision or with eye movement, and the latter could affect filming, particularly with a rolling shutter.

Oh, thanks. Those are indeed very good numbers to have.

Re: There's something off about LED bulbs

#725

Post by blackbear_ »

DebtDeflation wrote: post #675
twawaaay wrote: post #622

Earlier quoted context omitted.

As an amateur EE, I have analysed some of LEDs when I wanted to light up my kitchen counters. I wanted flicker-free LEDs with high CRI and temperature matching the rest of my apartment. I ordered samples of a lot of LEDs and found that almost all of them are using their parts, especially capacitors, well above the specs. Driving caps at well above their specs, at high temperature, basically ensures speedy failure. No…

>almost all of them are using their parts, especially capacitors, well above the specs Well, the LEDs themselves will last up to 20 years, so they have to make something in the bulb fail before that. Can't have people only buying replacement bulbs every other decade.

Not sure why you are being downvoted, when that is exactly what has happened with incandescent light bulbs one century ago:

> How exactly did the cartel pull off this engineering feat? It wasn’t just a matter of making an inferior or sloppy product; anybody could have done that. But to create one that reliably failed after an agreed-upon 1,000 hours took some doing over a number of years. The household lightbulb in 1924 was already technologically sophisticated: The light yield was considerable; the burning time was easily 2,500 hours or more. By striving for something less, the cartel would systematically reverse decades of progress.

https://spectrum.ieee.org/the-great-lightbulb-conspiracy

Re: There's something off about LED bulbs

#726

Post by rkeene2 »

marcosdumay wrote: post #587
terr-dav wrote: post #421

Earlier quoted context omitted.

An important point in the article is that CRI for LED bulbs does not meaningfully map to the light quality. >Oh, but: Experts agree that the color-rendering index doesn’t really index how colors are rendered. Some bulbs with a 90 CRI make things look wan; some with an 80 are passable. There are better, more useful metrics, but you can’t have them. Nobody puts them on the packaging. One lighting professional — an LED…

It's interesting how the led datasheets have all the useful information (spectrum, CRI, angular spread). But once manufacturers put them on a bulb, they will refuse to tell even what leds they used. At this point I believe companies are willfully refusing to inform their customers.

That could be because putting it on the box creates a liability that the LEDs are meeting those specifications -- just because the source LEDs claim to meet those specifications doesn't mean that the enclosure being sold using them as a component will actually produce that. Additionally, any change to LED suppliers/etc now means that the box also has to be changed.

In other words, what they are selling isn't the same as the thing in the box nor the aggregate of all the components (since they interact with one another).

Re: There's something off about LED bulbs

#727

Post by cal85 »

simongray wrote: post #493
cal85 wrote: post #367

Earlier quoted context omitted.

I guess you can't tell the difference? For me it's huge. I recently changed my bathroom downlights from dimmable LEDs to dimmable halogens, and it's so much nicer. The colour temperature was the same, so I guess it's not that. It's something else about the way they work. I don't profess to know why, but I can absolutely tell the difference, and I have a very clear preference now. And this is after a decade of me bein…

I'm sorry, but to me you mostly just sound like an audiophile talking about how vinyl sounds better than CDs...

Fair! Although I'm just reporting my preference and not making any contestable claims, other than that I can tell the difference. If someone can make an LED bulb where I can't tell the difference, then I'd fit my house with them, but it seems like this must be impossible or someone would have done it.

Re: There's something off about LED bulbs

#728

Post by t0bia_s »

I pay attention to colour temperature. Lights at home are usually lighten during evening, so it should be not more then 3000K - (for melatonin). I use mostly 2700K, tried even 2000K but that was too reddish for my taste.

Keep in mind that after sunset in nature there is only moon light that has blue spectrum. Fire, as light source is about 1700K.

Re: There's something off about LED bulbs

#729

Post by Whitespace »

I recently bought EcoSmart bulbs from Home Depot (they're a HD brand) that have a color temperature selector on the side (2700k to 5000k). But it also has an option called DuoBright, which will change the temperature in response to the standard cheap Lutron Diva dimmer I have.

It works *perfectly*! I can max the dimmer and it's bright white daylight, or I can dim it down to a very dim 2000k. There's no buzzing, no weird high-temp/low-light weirdness. It works magically. And it's the cheap option!

I replaced all BR30 & BR40 bulbs with it. I wish it came in more shapes! I'd replace every lightbulb in the house with them. I paid $5-$13 per bulb.

No one seems to know about them, not even the guy at Home Depot who worked in the aisle. He was surprised how much I raved about them.

Re: There's something off about LED bulbs

#730

Post by lambdaba »

cal85 wrote: post #727
simongray wrote: post #493

Earlier quoted context omitted.

I'm sorry, but to me you mostly just sound like an audiophile talking about how vinyl sounds better than CDs...

Fair! Although I'm just reporting my preference and not making any contestable claims, other than that I can tell the difference. If someone can make an LED bulb where I can't tell the difference, then I'd fit my house with them, but it seems like this must be impossible or someone would have done it.

Just came to say I agree with your assessment 100%. I think it's about the fact that incandescent light is a broader spectrum. It seems to affect the say shadows are cast etc. It's just not as nice as incandescent.
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