That 60W-equivalent LED: What you don’t know, and what no one will tell you

[budm]

http://www.edn.com/electronics-blogs...will-tell-you-

So far my LED lamps I used in real world last about two years (It is on about 2 hours a day), it lasted as long as my CFL but at higher price.

[RJARRRPCGP]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

So far my LED lamps I used in real world last about two years

Only 2 years?! That's like a cheap CFL! Probably would be typical of a Feit brand CFL.

[mariushm]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

If you guys are interested in this subject, this guy does a lot of led lamps reviews:

http://www.youtube.com/user/electronupdate/videos

Yes, the cheapest led lamps are very hot inside and not designed to run for long times - even the packaging says the warranty is a couple or 3 years if you run them 2-3 hours a day.

Some of the better led lamps like the Phillips higher end ones use 130c rated Rubycon capacitors and some Cree lamps use good Nichicon capacitors that

[cheapie]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

I've only had about 2 or 3 CFLs die ever, and I've been running nothing but them (and a few LED bulbs) for about 5 years now...

[Longbow]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

I find Ed's article to be totally ignorant. There is no useful information given there except the general idea that lighting fixtures can get hot.

He did not bother to offer specific information on any of the products he "discusses". But he does mention numerous times that we - the readers - are imbeciles.

What could have been included in such an article, but wasn't, is information about the types of CFL's and LED bulbs that are currently available. There is no comparison between the efficiency of a CFL vs an LED bulb of the same power rating.

Whether we're talking about CFL's, LED's or electrolytic capacitors - for every 10 degrees (C) rise in heat, you will cut the life span by 1/2. Recent LED bulb construction features high power Luxeon LED's that emit lots of light - and they get hot. No surprise there. And lifespan is affected by heat. Also no surprise. The fact remains that LED's are more efficient in producing light watt for watt than CFL's. If you have a CFL that uses 19 watts, for example, and replace it with an LED bulb that uses 19 watts, you will have more light coming from that fixture. Efficiency - that's the point. Prices will change as "economy of scale" takes place.

I can't understand the point of Ed's rant. I guess he believes that LED's are just a way of duping consumers into buying useless products.

[kc8adu]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

so?
the first cfl's were junk too.
second or 3rd gen will get it right.
just wait till that happens.
i make my own led lighting.
the parts i use will be far too costly for mass production.but they will likely never fail.
cheap rules the market because folks are conditioned to buy on price.
and designing for cheap often means no safety margin.parts run right at absolute maximums.a hot day,no ac,and a closed up fixture=BANG!
now all led bulbs suck.

[Uniballer]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

I've been getting the Cree LED lamps (800 lumens, 5000K). So far, so good. If they had a 1500 lumen bulb on the market with a 10 year warranty I would buy it.

I did have some CFLs that clearly were putting out way more UV than they ought to (if I have the old Tek 475A under them then you can see the screen glowing for a while after turning off the CFL). These were Sylvania CF23EL/MINITWIST labelled Y836-2. I'll bet some others are worse.

[SeanB]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

I bought some cheap ones just for the driver boards ( easier to buy the whole thing and toss the junk heatsink) and the internal construction is a guarantee for failure. Poor thermal performance on the heatsink, poor thermal coupling ( you actually need to have a firm attachment and not rely on the thermal paste to hold the thing in place) and running the die at 90C are not good. One old PC CPU heatsink later ( scrapped PC from the skip) and it runs at 30C and with cooler electronics. 9W LED unit is about equal to a 40W bulb, so 2 are perfect room lighting as an uplighter.

[Longbow]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

Here is something worth ranting about. It isn't the heat of a light fixture. Or even the lifespan of an led. These days, green media tells us they made an awful mistake. We should never have used florescent lamp products because they contain mercury. Mercury is going to destroy the world. Or in green language, it will destroy the habitat.

I don't have the figures (someone...maybe?) but I think you can count the number of mercury atoms inside a 4-foot tube. They are needed to start the ionization process. Florescent lamps are far more efficient than incandescents, just like LED's are more efficient than florescents. Doesn't that count for something? A can of tuna fish has more mercury in it than a 4-foot florescent tube.

Yet, we have to call a haz-mat team to dispose of our favorite 5000 degree daylight tubes. I recently had to pay 1$ to dispose of 1 tube - because of the hazardous waste charge. Junk science at work, folks. Where has it brought us? I'm going to fix myself a tuna fish sandwich.

[rhomanski]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

Hope it's not radioactive from Fukushima.

[kc8adu]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

so we are just now in a panic about mercury in fluorescent tubes?
we have only been using them since 1939!
i wonder how much mercury did not go into the environment from the burning of extra coal because of the fluorescent light?
the big flap about broken cfl's is silly.
these are nos from 94?
look at the blob in this one!
glad i found this case of 24 at a yardsale for $5.
full wattage and full mercury.last a long time.

[Snav]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

I have been experimenting with LEDs for the last month or so. First thing I discovered is they get VERY hot. I used the load shown in pic for some testing and at 5.6w the temperature at the base junction exceeded 254deg(124C). After much testing with linear constant current and constant voltage supplies I found they need precision voltage and current limiting for best efficiency. And, using a 10w array, I found that the drive voltage can be from 26 to 38v so unless you adjust the driver per Assy it's not very practical. So far I have found an inexpensive(cheap?) SMPS constant current driver has been the most efficient although I have the array mounted on a stripped 3.5" HD frame for a heatsink it still gets to about 113deg(45c) in free air. The driver's output is a bit lower than the arrays' rating at 8.8w but I would seriously be concerned about stuffing it into an enclosure that was not force ventilated as the proximity of the components are so close it's hard to tell if the cap is hot due to the adjacent components or not. My next thought is to raise it off the board and check but I'm not sure what the lead length will do to the frequency.

[Uniballer]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

The truth is that I don't like CFLs very much. The low light output at startup really bugs me. I want LEDs that work well, and take even less power, and I want them to last a long time.

I bought a couple of these on Monday. So far, so good. I hope they come down in price soon.

[Uniballer]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

I know the Home Depot website in the link in my previous post says they are only available online, but they are in my local store, and that's where I bought them.

[Longbow]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

Well, it is misleading to say that LED's get very hot. Anything gets very hot if you pump enough current through it. That's the whole point. There are a lot of LED's available, and it is up to YOU to decide how to run them.

A typical 5mm LED is rated around 20-25 mA maximum current. That maximum is a limitation based on how much heat is produced at 20 mA. Try one and see. A single 5mm LED running at 20 mA emits more light than you would want for a front panel indicator, but not much if you want a survival flash light.

That same 5mm LED might have a life span of 2000 years if you run it at 1 mA or less. It will give off plenty of light as an indicator, too. But these days bigger is better. The Luxeons and similar units have a built-in heat sink, and are designed for high power flashlights that will blind you. I have one that runs just under 1 ampere through one LED (5 watts). That flash light is so bright that I am blinded by the reflected light, let alone the main beam. It is all relative.

[Snav]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

Well the issue is heat in existing fixtures. As most are designed simply to be safe up to a particular wattage of incandescent with no ventilation as that would contribute to heat buildup in uncontrolled areas. Regular incandescents run at 4-500deg while LED lights are maxed at 185. The LED also still creates heat from 70%+ of the power consumed. The LED I have been working with is a 3x3 array of one watt illuminators. Pic provided. when being driven at 9w they are about 80-85% as bright as a fresh fully warmed up 13w cfl rated at 850 initial lumens which draws 18w total.

Mounted on the old HD chassis as heatsink it just gets warm but mounted on a 60x60x20mm heatsink it gets to well over 185degF so if longevity is the requirement then throttled output by way of temp controlled PWM or possibly active cooling for use in an A19 form factor. I'm betting that they are going to cut output to control temp.

[kaboom]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

Well the issue is heat in existing fixtures. ...
Mounted on the old HD chassis as heatsink it just gets warm but mounted on a 60x60x20mm heatsink it gets to well over 185degF so if longevity is the requirement then throttled output by way of temp controlled PWM or possibly active cooling for use in an A19 form factor. I'm betting that they are going to cut output to control temp.

And light output, by extension, unfortunately.

If I was to believe their silly 50,000 hours claim, even if the inverter didn't die by then, that shiny LED will be down to half its lumen output. Oh sure, the good ones only have a 20% reduction after 50k, but do you honestly think those'll be used?

People say metal halides are harsh. Sure, most have a clear outer bulb and the arc tube is a small source, but at least there's some spectral (thermal) broadening. LEDs, with their narrowband spectra, are absurd. While the phosphor is somewhat wide, there's a break between the spike from the diode, and a valley with increasing wavelength, before the phosphor "catches up." Sure, CFLs also have "bright line" spectra, but at least the modern phosphors, 700, 800, 900, series have many bright lines interspersed. As they should be, for high CRI.

Those awful "cool white" LEDs- 6600k, with a CRI in the 50s or less, is not a viable replacement- for anything!

And what's with the misleading CCTs anyway? "Cool white" was always anything from ~3800 to 4500k or so. It was daylight whose CCT was 6500 or so.

Those silly LED pushers. People buy "cool white" LEDs, already familiar with CW fluoros, only to end up with ghastly light that makes similar colors appear muted and indistinguishable.

Having a CRI of 85 or better should be emphasized, rather than the CCT, typically misrepresented in "LED style."

Oh, wait. CCT is the only metric cheep LEDs can be classified by, since their CRI may as well be "random" or "undefined."

[goontron]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

i will take metal halides over LEDs any day! even with ballasts that sound like a lockedup motor.

[RJARRRPCGP]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

i will take metal halides over LEDs any day! even with ballasts that sound like a lockedup motor.

Same here, even if the ballasts sound like the Family Feud buzzer!

In Springfield, they're now usually only on private properties! Because of the LED crusade of 2012.
(2013 for most other towns that got LED street lights in Vermont.)

-> Me thinks, are Rutland and Ludlow the only cities left in Vermont that still have the metal vapor lights for the majority???

Go over the border to New Hampshire, things are majorly different! It looks like heaven for metal vapor light lovers!

If you hate LEDs, New Hampshire will give you relief!

[kaboom]

Re: That 60W-equivalent LED: What you don't know, and what no one will tell you

i will take metal halides over LEDs any day! even with ballasts that sound like a lockedup motor.

Same here, even if the ballasts sound like the Family Feud buzzer!

I made this 150W MH "portable" thing with a parabolic reflector and ballast mounted on a base. A bit clunky, yet totally self contained.

Let's just say it kept me from "going mad" in this basement with abysmal lighting I was doing work in. I'd almost say it was pleasant because of such wonderful lighting.

It's great for crawlspaces, too!

LEDs? Nah- even with all their light, you never actually see anything.

Because of the LED crusade of 2012.
(2013 for most other towns that got LED street lights in Vermont.)

Wait, they actually get hot enough to melt the snow that accumulates on them?

Or will they be changing them back out next year after our "wonderful" winter so far?

There was a "learning experience" with LED traffic lights somewhere. See, they didn't get hot enough to melt the snow and remain visible, so the "fix" was.... to add heaters to the traffic lites!

"LEED," indeed, bwahaha!