LED lighting ..future or not ? tests + pics ..then dimming control questions!!

[JinMTVT]

hi all!!
First post here! was linked by the great IVB from www.avsforum.com/CCQ forums

so here is a copy paste from a thread i just started over at diyaudio.com

hope some of you will find it interesting


-------------------------------------------------------------

I have ordered a few expensive pieces of LEDS
from Seoul Semiconductor
http://www.acriche.com/en/
wich are AC 120V driven direclty
( there are a 2 resistors on the pcb though )
I believe that they use the up and down of the AC
to drive and reverse/drive 2 different 1W section of the LED pannel, something like that ..quite simple
and that removes the complexity associated with LED electronics and voltage requriements ...

So that said , i now have 10 6500K
( was the only one avaiable by then) 4W ( 2 2W leds on each pcb ) "specialist" Acriche LED units @ 21$USD each from www.avnet.com
I will be receiving some 3000K version of the same leds this week for further analysis.

My point was to test the usability of leds for indoor lighting to replace annoying CFL bulbs and plain ridiculous incandescent light bulbs.

So i tried to compare them to what was available at the moment in my house to see how they could be used.

Here are a few samples of the tests i did for the interested of you.

1- 6X4W LEDS 6500K ( total 24W )dispersed on the ceiling VS 1 phillips daylight 27W CFL ( quality one @ 5500K)

Please do not mind the color temperature difference, i tried to attenuate it by using automatic white on my camera ....the camera was setup to give the best exposure that represented the actual scene as seen with my eyes.


27W CFL
http://img526.imageshack.us/img526/5530/dsc05398ho4.jpg

24WLED "star" setup
http://img526.imageshack.us/img526/6910/dsc05399eb8.jpg


following test was done at kitchen
2 led modules for 8W total were used VS
2 50degree halogen 50W spots
( please keep in mind here that the leds are 110degree patern, so there is no bright spot as seen with the 50degree spots ... thought i do not see it would be a problem if the leds were recessed in a cone spot enclosure ..to be tested )

2 50W halogen spots 50deg.
http://img526.imageshack.us/img526/1473/dsc05403lk0.jpg

2 4W acriche led modules
http://img182.imageshack.us/img182/6635/dsc05405db6.jpg




Now this test is again 2 4W acriche led module VS 3 30-40W candella type incandescent in a round mount under a diffusing white glass ornment

i'd say that the total light output was a little higher with the 2 leds than with the incans here ..

incandescent lighting
http://img526.imageshack.us/img526/5530/dsc05408br7.jpg


2 4W LEDs
http://img526.imageshack.us/img526/2987/dsc05409kq9.jpg


Again do not take care of the color temperature..
only brightness and illumination is in test here



I like what i've tested, and i will be investigating those new LEDs again much soon,
as i intend to use them in 80%+ of my future house lighting !!

What do you think ?

have you personally done tests with leds?

i know there are many more efficient modules,
but none has the retrofit possiblity and the easiness of those 120V AC units ..




Now onto the dimming subject ..


how do regular dimming control works ?

what do we want to control those leds?

i've read that LEDS are current driven units,
but they regulate their current depending on the feeded voltage ..do not know if those are of the same...

I'd very like to be ablet o test those leds with some dimmer, i'll try to purchase one this week end at the store to see how it works wiht the leds.

i've also read that some dimmers work by switching on/off at different speed so there is no power loss from dimming .

my ultimate goal is beeing able to use those leds with regular Z-Wave dimmers to setup automation correctly

neway, any info on dimmers for lighting will be appreciated!

 

[Quixote_1]

Thanks for the informative post. I've always been curious about LED lighting, and I look forward to hearing about your experiences once you've implemented dimmers. I'll be using Insteon with my lights (I have the basics in place), and I've been thinking about making the switch to LEDs, though by the looks of it they are much less bright than the regular incandescent bulbs. I do like that the bulbs would last for 4 years if left on for 24 hours a day, however. Could you let us know how much they cost?
I have sconces on my wall in the livingroom. What would I need to do to set these up in a regular fixture?
Thanks again for the info.

 

[garylm]

My quest for LED lighting began with a $24 rope light from Costco. It had noticeable flicker and was far too blue. I have since purchased the warm white LED ropelights from American Lighting. They cost $75 for a 15-foot string. They still have a greenish cast and look nothing like the color on their webpage, but the flicker is gone. I'm guessing that they are using a full-wave rectifier in the cord, whereas the Costco rope seems to be running AC directly to the LEDs. I'm hoping to get an even warmer string.

I'm not sure, but diodes, whether there's a rectifier in the line or not, should be able to handle any kind of dimmer you throw at them. It they're using a transformer to drop the voltage, I think you'll be wanting a magnetic dimmer. I think you're out of luck if there's a switching power supply in the line.

 

[Timoh]

I despise CFL and LED light because of the colour temperature. Mind you I was recently surprised when I purchased a CFL for the girlfriend and it is surprisingly warm. The neighbour's ourdoor light is white and cold, but hers is warmer. Not too bad.

So I am really interested in the temperature of the LED lights.

I also know that some HA switches have a minimum wattage value they can operate. I think it's usually 10 or 15 watts. I wonder if an ultra low wattage device like an LED light would not load a HA dimmer switch to function properly?

Tim

 

[CollinR]

LEDs can be any color temperature you want however if a single LED the temperature will be very narrow.

They are the future of lighting, it's getting hard to find a flashlight that doesn't use LEDs now. LEDs are superior to but incandescent and compact florescent in just about every way. They last longer, much more durable, the precision light spectrum can be a bonus or LEDs can be mixed to create any range of temperatures.

Also some are very very bright for their size so I assume fixtures will significantly change too.


BTW I want IR christmas rope light, wouldn't that be too cool.


For those with CCTV you know Christmas kicks @ss for more then one reason.

 

[JinMTVT]

again pasted from diyaudio
-------------------------------------
I did a bit of testing with the new 3000K Acriche
LEDS that have arrived today.

I have to admit that i am severly deceived.
I was waiting for a CRI90+ warm white 3000K
nice and mellow/yello colored light ...

For starters, as with all LEDs, the warmer the color temp,
the less output the LEDs produce.
this resulted in estimated 30-40% less light output than the 6500K ones ( usable light without additional lens here )


here is the 4 4W leds VS incan for color comparison

here u can see the blue/green tints of the supposed 3000K led
http://img171.imageshack.us/my.php?image=dsc05416xh5.jpg


comparison shots of the 16W 4 units 3K K Acriche
VS ~ 100W incandescent

http://img171.imageshack.us/my.php?image=dsc05417xf6.jpg

http://img99.imageshack.us/my.php?image=dsc05418js2.jpg



The onto the halogen test ...again 4 4W vs 2 50W 50deg spots

http://img244.imageshack.us/my.php?image=dsc05419vs2.jpg


http://img171.imageshack.us/my.php?image=dsc05420hs0.jpg




Here is a quick setup of under cabinetry lights using those same 4 4W acriche

i believe that it is where they perform the best
though a bit too bright ( i'd prefer half bright at twice the location ...or a bright led rope )

the pictures may be blurred cause i am using slow speeds with handheld shots ...but the last one shows pretty much what the color and light output looks like in real...it is pretty much white white
but surely not warm white at all ..

http://img99.imageshack.us/my.php?image=dsc05426cs5.jpg

i'm tired now ..

let me know what you think ..
but i am going to sleep with much deception

 

[garylm]

LEDs can be any color temperature you want however if a single LED the temperature will be very narrow.

Last year at CES I saw some LED desktop lamps that were achieving a nice warm white by blending yellow, red, and blue-white LEDs in a cluster. Even RGB LEDs consist of a cluster of three diodes (see fellow HA enthusiast Gerry Duprey's RGB LED project page for more info). Producing an "any color" LED from a single diode junction would be a chemistry puzzle.

 

[Timoh]

Well the way I see it... It'll be a few years before they are really refined, nice, easy on the eyes, not to intense, etc.

Look at CFLs... They came out... About 10 years ago? Started being adopted ~7 years ago and only really went mainstream ~4 years ago. And only now I find they are becoming refined with better colours, dimmable, shapes, intensity, etc. I think about 2015 we should be ready and there will be refined LEDs as incandescant replacements.

For the next 2-3 years, I think there will be lots of experimenting and pondering at JinMTVT has done.

Those 3k versions do look nicer than the others. Too bad about the intensity. As you say, perfect for spot lighting and specific applications.

Thanks
Tim

 

[Steve]

I would like to see a nice natural 5500k flood LED. I always use 'natural' light where possible and try to avoid the warm/cool stuff. You'd be surprised how much different things in the house look, with all your decorations being their true colors, etc. But, as many things, this is a highly personal thing, hence the manufacturers need to have many choices to appeal mass market.

 

[garylm]

I'm using the LED ropes for indirect cove lighting. The color isn't very appealing, but it works great coupled with a PIR to light your way through a dark house. (I think it's silly to control fluorescents with a PIR - all that cycling on and off doesn't save you much energy, but LEDs don't mind all that cycling.)

OLEDs featured large at CES this year. Samsung had some super bright 21" prototype OLED flat screens on display. The blues weren't quite ready for prime time but almost.

I think the printable OLEDs look promising for home lighting. Some OLEDs shown at CES were printed directly onto a polymer sheet and then laminated. An entire cookie-cutter-shaped region on the sheet was a single LED element, and various colors were possible. You could have an entire sheet be a single LED, and then fasten that sheet to the underside of your cupboards for some very subtle, diffused lighting. Do that under your cupboard shelves to light the interior. Heck, use the stuff as shelf paper...wall paper. And we'll be able to come up with some cool, backlit(only not backlit) control panels. Cut out your own button panels from sheets of OLED. Kids could build their own night lights from an OLED collage.

 

[JinMTVT]

OLED are the future of home lighting ...the current problem is the time it'll take before they are ready

GE has made alot of advances using white OLED
problem is the same as with regular LED :
- life vs brightness
- brightness vs efficiency
- chromatic qualities/metrics

i am trying to get a hold of some EL pannels ( electro luminenscent ) to test some area lighting to see the effect it as
in a room ..problem is the light output is seriously low, and if we crank it up, the life goes down ridiculously
( i was quoted 7000hours @ 50% brightness for a 40-60cmd/m2 ..or 3000 hours @ 50% for a 80-100cm/m2 )

then, to sufficiently light up a room, you have to go in the 40-100 square feet of panels
5wich then makes the price of the setup completly ridiculous ( @ 25$USD/square foot quoted from china )
with less than 7000 usable hours...this is a pretty expensive tech

the thing is that having your complete ceiling acting as a light is pretty much the best u can ever hope for

no spots, no glare, no shadows...everything is almost perfect

then there is color consistency wich all the manufacturers i've discusses with weren't truly able to quote



OLED and LED are the future of lighting ..
problem for me is that i am building my house NOW
and i do not want to invest and plan a lighting solution that i will want/have to replace within 2-5 years
building this house for family for the next 25 yeasr

 

[Timoh]

I would design as normal/incandescent.

I would very very surprised if the LED manufacturers aren't striving for "backwards compatibility" with incandescent. They have to. They don't have a choice if they actually want a market for their products.

If you could only put LED lighting in new constructions, which are specially designed for LED lighting, think about how long it would take to convert folks over.

Thinking about it this is how the CFL market grew. They made CFL backwards compatible to incandescents. How many people would have CFL today if it took new special designs, considerations, sockets, switches, etc.

Tim

 

[murphy]

hi all!!
First post here! was linked by the great IVB from www.avsforum.com/CCQ forums

so here is a copy paste from a thread i just started over at diyaudio.com

hope some of you will find it interesting


-------------------------------------------------------------

I have ordered a few expensive pieces of LEDS
from Seoul Semiconductor
http://www.acriche.com/en/
wich are AC 120V driven direclty
( there are a 2 resistors on the pcb though )
I believe that they use the up and down of the AC
to drive and reverse/drive 2 different 1W section of the LED pannel, something like that ..quite simple
and that removes the complexity associated with LED electronics and voltage requriements ...

... any info on dimmers for lighting will be appreciated!

Hi,

partly I'm living in Berlin/Germany, partly in NE-Texas. So I refer for a lot of information to

www.leds.de

Also they sell the same stuff, from the same South Korean companies as distributors in the US, basicly at the same price-level (if you consider $ 1,45 for 1 Euro).

I tried to light an entrance area with a lot of small LEDs, 1 lm ea.
Those producing light as around a 1 W (flashlight-) bulb but consuming only 20 mA x 3.3 V (DC).
Basicly those little LEDs -as every other LED- are available in every color (red, green, yellow, orange, several blues, brite white, warm white).
So far good numbers:
60 warm-white LEDs in the ceiling are producing the light of a 60 W bulb, and yes they do. All in series on a constant current source.
However I do not realize this project in this way
because it turned out that my project is giving not warm white light, but white with a (too) strong touch of yellow/green!

I also bought 3 very little white LEDs (same datas, SMD at the end of wires!) for emergency-panel-illumination for the panel of my little oldtimer-plane, which are working excellent.

And I also bought (3 month ago) stronger LEDs: real warm white, 3.3 V, 350 mA (max 1 A but than you need some cooling and the efficiency is going down), those I need as a spot light.

The efficieny of LEDs is a little better as fluorescent lights, the lifetime nearly infinte.

When dimming, you need to regulate the current, not the voltage! The current is producing the light, not the voltage. While the current can vary from nearly zero to the peak-value, the voltage is changing only between (maybe) 2.5 to 3.3 (max!) Volts. So think about a fitting interface for dimming!

IMHO there are no fluorescent lamps as energy-saving-lamps in 3 years, all will be lighted with LEDs: Cars as appartments etc. And the prices will go down. Think of Moores Law.

cu E.

 

[garylm]

When dimming, you need to regulate the current, not the voltage! The current is producing the light, not the voltage. While the current can vary from nearly zero to the peak-value, the voltage is changing only between (maybe) 2.5 to 3.3 (max!) Volts. So think about a fitting interface for dimming!

Isn't there a resistor in series with our LED?