# Are 120 volt home LED bulbs technologically inferior to the new flashlight LEDs?



## HighlanderNorth (Sep 21, 2011)

When we first turned 16 and got cars, we lived in a rural area, and my friends and I bought spotlights that plugged into our cigarette lighters in our cars. We used them to check out deer at night in fields and clearings. We didnt shoot them or anything, we just watched them for a few seconds before moving on.

Anyway, we had to use spotlights that plugged into the cars' 12v electrical system, because a standard flashlight that runs on a few portable batteries would've never been powerful enough.

The point is, the more power you have available from your power source, the brighter your light will potentially be. Or at least it should work out that way.

Now, obviously the most powerful power source most of us have access to is our home 120v outlets. These offer even more power than a 12v car system, and much more power than a portable flashlight with a couple/few small batteries....

However, I was again at Lowes yesterday looking at LED bulbs for home use, and I was comparing their power and brightness capability. Now we can all buy portable LED flashlights that offer around 2200 Lumens, so you'd assume that a 120v LED bulb would be potentially much, much brighter....... But they dont seem to be nearly as bright as the small flashlights are! That doesnt make sense to me.

The most powerful LED 120v bulb I found there was a 90w equivalent bulb, which had around 1100 Lumens. Thats all! The rest had much less..... What was more ridiculous, was that it costed like $70!

I can buy 2 compact fluorescent bulbs that are 90w equivalent, that run at 1500 Lumens for $12.99! The only benefit is that the LED will last like 30-40,000 hours instead of 8,000-10,000 hours. 

**Question 1: But the CFL is 30% brighter, and although it lasts only 1/4 as long, it costs 1/10 as much! So whats the benefit?

Another thing was that this 90w LED was listed at 23w, which is the same as the CFL, so it isnt any more efficient.

Also, another thing that confuses me is that the LED had only 1 bulb that was rated at 23w, so why isnt it brighter if it's bulb can use 23w of electricity, when a 3w flashlight LED can produce 2200 lumens with 4 batteries. Obviously a 100w bulb should be brighter than a 60w bulb, right?

**Question 2: Now the bulbs I'm comparing(120v LED vs CFL) were both floodlights, which are both surrounded by a reflector on one side, and focus their light on roughly a 150 degree arc, instead of a regular bulb which sends its light out in all directions, but since it does have to spread its light out to about 150 degrees, it isnt as bright as it would be if it were focused in a 20 degree arc like a flashlight. But still, it should be capable of much more brightness than it is, since its bulb is more powerful and it has a higher power source.........No?


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## idleprocess (Sep 21, 2011)

Incandescents care little about heat; LED's do. That's the primary reason you're seeing LED flashlights outperform LED bulbs - their thermal limitations are far fewer.

The typical LED flashlight is used for minutes at a time with a duty cycle over time that's very nearly zero, and has the benefit of substantial heatsinking/great airflow. I find that I use mine for *seconds* at a time day-to-day. Under these conditions, the 25k/35k/50k/100k rated operating lifespan of the LED's translates into near-_eternity_ working lifespan. Those LED's can be run at >100% of their rated current since they'll likely never see a quarter of their rated operating life and probably won't run for long enough during any one activation to overheat. The market will also pay a premium for some modest increase in lumen output, thus the latest LED's go into flashlights.

Contrast this to a LED light fixture, which must run for hours on end, operate with an appreciable duty cycle, and is typically expected to do so in a fixture with marginal heatsinking and little if any airflow. Suddenly, those tens of thousands of rated hours translate into a pretty fixed number of years' worth of working lifespan. Warranty claims become a big concern with this kind of general consumer product, so older, proven, and less efficient LED's go into these products, often underdriven to increase longevity. People generally buy light bulbs on cost, so every dime away from your price point - _$20 is a good price point for LED bulbs in the 40W/60W equivalent nowadays; $10 even better_ - equals lost sales. Unlike the flashlight market where the brightest is the bestest, you need only hit a given level of light in the incandescent replacement market.

I have an LED bulb I bought in late April that's been running 24/7 - that's roughly 3600 hours or a bit more than 14% of its rated life. If it fails before that time, I won't be surprised (nor filing any warranty claims) since it's in a nearly fully-enclosed fixture.

The typical incandescent socket is a less-than-ideal place for a LED of any flavor, so total _electrical power_ tends to be strictly limited to whatever the manufacturer deems their LEDs/drivers can survive in the lowest-common-denominator location (a completely enclosed fixture or a recessed can fixture). It's also worth noting that most LED flashlights are pushing 5W or less power through the LED while LED bulbs are usually closer to 10W - at least in the >=40W incandescent category.

If you want to see LED's really shine in general-purpose lighting, you'll need to wait for purpose-built fixtures to come out that address the unique power, thermal, and optical requirements of LED's. The commercial market is slowly buying into these purpose-built fixtures - expect it to take several years for those kinks to be worked out before you start seeing affordable residential-grade fixtures.


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## HighlanderNorth (Sep 21, 2011)

idleprocess said:


> Incandescents care little about heat; LED's do. That's the primary reason you're seeing LED flashlights outperform LED bulbs - their thermal limitations are far fewer.
> 
> The typical LED flashlight is used for minutes at a time with a duty cycle over time that's very nearly zero, and has the benefit of substantial heatsinking/great airflow. I find that I use mine for *seconds* at a time day-to-day. Under these conditions, the 25k/35k/50k/100k rated operating lifespan of the LED's translates into near-_eternity_ working lifespan. Those LED's can be run at >100% of their rated current since they'll likely never see a quarter of their rated operating life and probably won't run for long enough during any one activation to overheat. The market will also pay a premium for some modest increase in lumen output, thus the latest LED's go into flashlights.
> 
> ...


 

Are any purpose built LED fixures available yet, and how long is it likely to take for them to become widely available?

When they do come out, what will be different about them, and how expensive are they likely to be? 

Are they likely to be geared towards the high-end home market, at least at first?

How will they be able to get rid of heat if the fixture is mounted inside a hole in the ceiling, or hanging just below the ceiling, and enclosed inside a glass dome? 

Maybe producing purpose built LED lamps would be the easier way to go, since lamps are usually out in the open, surrounded on all sides by air, so the heatsink can receive air flow more easily and dump its excess heat out into it.

What is a duty cycle? Is that the lifespan?


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## idleprocess (Sep 21, 2011)

HighlanderNorth said:


> Are any purpose built LED fixures available yet, and how long is it likely to take for them to become widely available?
> 
> When they do come out, what will be different about them, and how expensive are they likely to be?
> 
> Are they likely to be geared towards the high-end home market, at least at first?



They're available for the commercial market at the moment. Cree has some of the highest-visibility products right now for interior lighting. 

In my region (Dallas/Forth Worth), the local 7-11's have replaced _all_ of their outdoor lighting with LED that's difficult to distinguish from the metal halide / florescents they were using; after 2 years of service I have noticed all of one outage at the 2 locations I see with some regularity.

The TCO for LED isn't quite as good as T8/T5 floro, so it will take time for the fixtures to gain traction in the market. They do offer the advantage of near-zero maintenance, the possibility of tuneable output (in terms of lumens and color), and zero aversion to start/restart cycles.

The fixtures I've seen for the commercial market outdoor arena tend to be special-purpose fixtures such as strip lighting, bay lighting, sign backlighting, and parking lot lighting (so-called "cobra" fixtures and the like). LED has been gaining stead traction in the niche field of wall-washing for many years thanks to the likes of Color Kinetics since they can be distributed across many floors due to their near-zero maintenance. For indoor purposes, I see fixtures for suspended ceilings, recessed fixtures (Cree makes some of these, available under Home Depot's "EcoSmart" brand), and accent lighting.



HighlanderNorth said:


> How will they be able to get rid of heat if the fixture is mounted inside a hole in the ceiling, or hanging just below the ceiling, and enclosed inside a glass dome?
> 
> Maybe producing purpose built LED lamps would be the easier way to go, since lamps are usually out in the open, surrounded on all sides by air, so the heatsink can receive air flow more easily and dump its excess heat out into it.


By simply attaching the LED's to some mass of heatsinking (copper or aluminum being optimal) with some potential airflow, you'll be able to reduce the LED temperatures significantly and choose between increased lifespans or increased brightness.

Mounting LED's in a recessed socket with no heatsinking/no convection, and within the envelope of an incandescent light bulb will *always* result in a compromised design. That they can replace 40W/60W _(and allegedly 100W if Switch Lighting ever launches)_ is truly amazing.



> What is a duty cycle? Is that the lifespan?


If I operate outdoor lights 8 hours a day, that's a 33% duty cycle. If I operate a flashlight 5 minutes a day (1440 minutes), that's a 0.34% duty cycle. Devices that run intermittently often have easier lives than those that operate continuously - this is especially true in the case of solid-state devices like LED's that have no "startup cycle." Drive a flashlight at 120% for an hour or so, and so long as your heatsinking is sufficient, noone is going to notice should it dies after a thousand hours of operation since that will likely be *years* outside of the warranty period.

Remember the Luxeon V "portable" from 2005-ish? Brightest LED on the market for some time. Rated at 500 hours operating lifespan. I've got a few lights with said LED and they've going on 4 years old apiece without skipping a beat.

A flashlight's incredibly low duty cycle along with its pretty low average _operating_ timespan (the time that it's actually running) means that its _working_ lifespan (shelf life, or span between first-ever use and last-ever use when it dies) is nearly infinite ... as far as the LED goes.


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## cy (Sep 21, 2011)

Sam's club has been a leader in selling compact florescent and 120v LED lights. 
still quiet pricey for LED fixed lights. last one I purchased was $37 last xmas
lots has happened since then. 

looking forward to buying a fixed LED light with latest technology. hopefully MUCH less $$


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## Ken_McE (Sep 21, 2011)

HighlanderNorth said:


> Are any purpose built LED fixures available yet, and how long is it likely to take for them to become widely available?



Discussion of two foot square LED light panel. In 2007 when the thread was started such lights were scarce. When I went to replace it in 2011 I found a whole raft of superficially similar products.

There are also a number of threads here by people who got tired of waiting and brewed up their own awsomeness. Just mouse around in Fixed Lighting.

(PS, when you quote something, trim your quote to just the important bits)


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## blasterman (Sep 21, 2011)

> If you want to see LED's really shine in general-purpose lighting, you'll need to wait for purpose-built fixtures to come out that address the unique power, thermal, and optical requirements of LED's.


 
I agree with everything in your posts, but the reality is that purpose built fixtures or lamps are the exception in residential and primarily intended for commercial use. The catch-22 is that commercial/industrial lighting has been using efficient lighting for years in the form of metal halide or fluorescent, and this means LED alternatives have to work much harder to be competitive. Since residential lighting is in the stone ages it only takes 50 lumens per watt of LED to seem like a technological marvel. When you're comparing LED bulbs to compact fluorescents, which were a hack to begin with, it tends to slant the perspective technology bell curve a bit 

Built to purpose LED fixtures certainly have things easier from an engineering standpoint though, and Cree has shown these fixtures tend to be the top of the food chain. 

In terms of retrofits LED bulbs, which unfortunately get most of the press, 90% of the problem is strictly thermal. In my tests 3 XPGs driven at 700mA and mounted on a 5x5" aluminum plate will get it warmer than Cree guidlines in far less than an hour of run time and uncomfortable to hold. Compare this to flashlight designs posted daily which have less radiant surface area and yet the owner is claiming it runs cool to the touch. So, the runtime on the torch must be very short, and/or the LED's simply aren't making proper contact with the slug. In short, the custom torches presented here are 'cool' in many design respects, except for attention to thermal transfer coefficients so they aren't a good frame of reference. Trying to cram LED's into MR-16 formats is where the trouble starts, then again I'm sure Fred Flinstone had these in his cave (along with recessed lighting).

I'll insert my common rant that you'd be shocked at what you can build with current DIY LED parts rather than wait for Home Depot or Lowes to pull it off the container ship from China. Commercial grade, AC/DC LED supplies from 10-150watts don't cost any more than conventional ballasts and have efficiency ratings in the stratosphere. With the Cree XM-L and MP-L, along with dozens of Bridgelux emitters and nifty heat sinks like the new Wakefields getting multiples of 1000 of lumens of gorgeuous warm-white that will last decades is simply limited to the imagination, not existing technology.


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## idleprocess (Sep 21, 2011)

blasterman said:


> I agree with everything in your posts, but the reality is that purpose built fixtures or lamps are the exception in residential and primarily intended for commercial use. The catch-22 is that commercial/industrial lighting has been using efficient lighting for years in the form of metal halide or fluorescent, and this means LED alternatives have to work much harder to be competitive. Since residential lighting is in the stone ages it only takes 50 lumens per watt of LED to seem like a technological marvel. When you're comparing LED bulbs to compact fluorescents, which were a hack to begin with, it tends to slant the perspective technology bell curve a bit


I should have lead that statement with a more prominent *If...*

Florescent and arc lighting being more or less tapped out technologically, improvements in LED will likely lead to fixtures with a relatively low die count running at a low enough power level that the fixtures can last for well over 100k hours at great electrical _and_ cost efficiency. 

That, or the Mayans kill us all next year, so it's not worth worrying about...



In another decade or so, I think LED will likely gain some ground in the commercial sector, which might lead to some of the winning concepts being pared down into residential designs where the "no maintenance" factor will be appealing enough to replace some of the more utilitarian fixtures (think of the numerous cheap flush-mount fixtures proliferating throughout most homes). How often do you really think about some of these fixtures - in back hallways, secondary bathrooms, closets, utility rooms, garages, etc - _except when they malfunction_? Paying $40-$60 complete for one of these and suddenly having something as reliable as the switch that operates it could go over well.

Whether LED will begin to displace some of the other well-entrenched incandescent venues - accent lights, chandeliers, pendants, recessed lighting - remains to be seen.



blasterman said:


> I'll insert my common rant that you'd be shocked at what you can build with current DIY LED parts rather than wait for Home Depot or Lowes to pull it off the container ship from China. Commercial grade, AC/DC LED supplies from 10-150watts don't cost any more than conventional ballasts and have efficiency ratings in the stratosphere. With the Cree XM-L and MP-L, along with dozens of Bridgelux emitters and nifty heat sinks like the new Wakefields getting multiples of 1000 of lumens of gorgeuous warm-white that will last decades is simply limited to the imagination, not existing technology.


Agreed. I find that I use my homebrew indirect lighting setup in my bedroom constantly, and it's more than enough light for moving around the bedroom/bathroom. I need to get moving on some of the other secondary lighting projects I've been kicking around for _years_ now, in fact... the XR-E's I sourced for them aren't getting any newer.


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## blasterman (Sep 22, 2011)

What you said...

In the commercial / industrial sector your customer's tend to be a lot more skeptical and educated in terms of fixture benefit._ "Ok, you want me to replace 1,500 T8 fixtures using efficient reflectors with LED? Fine....where's the cost analysis breakdown so I don't get fired?"_

Yep, we're hitting +140 lumens per watt with production Cree's, but it's going to be quite awhile before it translates into actual fixtures, and then you have the usual 'state of the art' mark-up premium. So, it's a specialty market mostly with very few mainstream products that have exceptional performance like the LR-24.

For residential, I'm noticing that LED retrofits bulbs tend to be competing more with CFL than incan - at least in terms of the people that buy them. That's hysterical on many levels and says a lot about the mental make-up of the comsumer market, but it is funny.

In terms of dedicated fixtures for residential, that would be cool, but I'm still skeptical of the market for this. Most people want light bulbs that screw into holes in the ceiling, and as long as manufacturers keep riding the extreme edge of thermal performance they'll eventually fill that need {shrug}.


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## LEDninja (Sep 22, 2011)

:welcome:



HighlanderNorth said:


> Are any purpose built LED fixures available yet, and how long is it likely to take for them to become widely available?


Cree has the CR14 to replace 1'x4' fluorescent fixtures. The CR22 & LR24 to replace 2'x2' fluorescent fixtures. The CR24 to replace 2'x4' fluorescent fixtures.
2000 to 5000 lumens. 73 to 110 lumens per watt.
http://www.creeledlighting.com/Products/Architectural-Troffers.aspx
The sheer size of the fixtures provide lots of surface area to dissipate heat.
1152+ square inches for the 2'x4' fixture.
575+ square inches for the 1'x4' and 2'x2' fixtures.

Cree also have fixtures to fit 6" & 4" downlights.
http://www.creeledlighting.com/Products/Downlights.aspx
The CR6 is sold under the Ecosmart label at Home Depot. Note you have to remove the plate at the top of the can to turn the enclosed fixture to a ventilated one for the CR6.
How to install Cree's CR6 LED downlight
http://www.youtube.com/watch?v=2UKP_lvzY3A




HighlanderNorth said:


> When they do come out, what will be different about them, and how expensive are they likely to be?


For pricing use the Locate your closest Cree Distributor page to find a distributor and ask.
http://www.creeledlighting.com/Where-to-Buy.aspx




HighlanderNorth said:


> Also, another thing that confuses me is that the LED had only 1 bulb that was rated at 23w, so why isnt it brighter if it's bulb can use 23w of electricity, when a 3w flashlight LED can produce 2200 lumens with 4 batteries. Obviously a 100w bulb should be brighter than a 60w bulb, right?


 WHOA!
Where can you find a 3W flashlight that can do 2200 lumens?
The SSC-90 driven at 9A can do 2200 LED lumens. 9A*3.6V=32.4W!!!
A 3W flashlight 700mA*3.6V will give you 200-260 LED lumens, 150-200 out the front.
Remember a household bulb is usually warm white, not the cool white of a flashlight.


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## SemiMan (Sep 22, 2011)

HighlanderNorth said:


> **Question 1: But the CFL is 30% brighter, and although it lasts only 1/4 as long, it costs 1/10 as much! So whats the benefit?
> 
> Another thing was that this 90w LED was listed at 23w, which is the same as the CFL, so it isnt any more efficient.
> 
> ...


 
A) A 3W flashlight does not produce 2200 lumens. Any 2200 lumen practical flashlight I have seen is using more like 25-30 watts from the batteries to get 2200 actual out the front lumens.

B) These things are designed to last and are tested for the most part. They have done Lighting Facts, LM-79, UL, etc.

C) They have what is usually a small AC power supply which costs more than a DC\DC.

D) They have limited heat sink capability which is usually the big stickler.

E) They are warm white where efficiency tends to be lower.

F) You are buying online, not from a low markup web-shop like DX.

G) It is assembled for you, unlike a roll-your-own ... if your time is worth anything to you.

H) Give it 12 months ....


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