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Old 09-10-2006, 05:45 PM   #51
aropal
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Quote:
Originally Posted by BarraCuda™ View Post
This is a narrow beam spotlight, it produces a very bright spot thats why they "claimed" to be so bright. If you spread the beam, it would be rather dim.
This is a lumens value. This is not lumens per square metre.
It is immaterial what distribution you spread the light over when comparing the light output in total in lumens.

You have confused lumen and lux. Perhaps this site will allow you to understand the difference.

http://en.wikipedia.org/wiki/Lux

Incidentally I was attempting to demonstrate the fact that that technology has moved on a great deal since the data on which you have based you argument namely 55 lumens for 3 watts.

Indeed, you can rest assured that this small scale reseller pushing these things out for as little as 25 GBP a time is selling what is a long way from ‘state of the art’.
 
Old 09-10-2006, 09:37 PM   #52
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Quote:
Originally Posted by aropal View Post
This is a lumens value. This is not lumens per square metre.
It is immaterial what distribution you spread the light over when comparing the light output in total in lumens.

You have confused lumen and lux. Perhaps this site will allow you to understand the difference.

http://en.wikipedia.org/wiki/Lux

Incidentally I was attempting to demonstrate the fact that that technology has moved on a great deal since the data on which you have based you argument namely 55 lumens for 3 watts.

Indeed, you can rest assured that this small scale reseller pushing these things out for as little as 25 GBP a time is selling what is a long way from ‘state of the art’.
If you are talking about aquarium lighting, I dont see why light distribution shouldnt be taken into consideration.

Whats the point of having 135 lumens when it can only deliver that value on a small spot?

I did mentioned before brightness is affected by the voltage and reflector design. 55lumens is the rating given for a 3V forward voltage for a max 4V LED.

There is no point for a 1000 lumens fixture when the area covered is only 1cmx1cm? All along I'm trying to say that narrow beam LEDs are bright and wide beam LEDs are dim .. so simple

My view is very clear, by today's technology, there is no way 1watt LED can produce 170 lumens period.
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Old 09-10-2006, 10:19 PM   #53
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Quote:
Originally Posted by BarraCuda™ View Post
If you are talking about aquarium lighting, I dont see why light distribution shouldnt be taken into consideration.
If you are looking at a light that is described in terms of its lumen output then you have no basis for making disparaging comments in terms of its lux.

Quote:
Originally Posted by BarraCuda™ View Post
Whats the point of having 135 lumens when it can only deliver that value on a small spot?
The primary implementation of led lighting is that each element produces a small amount of light and then focuses it to a specific location. If you want more distributed light then you use more elements focussed on different areas.. If you want more intense light then you focus more elements on THE SAME area.

Quote:
Originally Posted by BarraCuda™ View Post
I did mentioned before brightness is affected by the voltage and reflector design. 55lumens is the rating given for a 3V forward voltage for a max 4V LED.
How is this relevant. All we care about is how many lumens are produced per watt.
In terms of keeping fish, plants and invertebrates we might also reasonable be interested in CRI such that the action spectrum of our captive organisms are catered for.

[Incidentally, there are numerous bright LED manufacturers which claim a CRI in excess of 80; the only questions remaining are with regard to the location in the spectrum of that missing 20%]

Quote:
Originally Posted by BarraCuda™ View Post
There is no point for a 1000 lumens fixture when the area covered is only 1cmx1cm? All along I'm trying to say that narrow beam LEDs are bright and wide beam LEDs are dim .. so simple
The area covered is not 1cm x 1cm. Each of the three led elements is itself 1cm x 1cm. There are numerous brands of Luxeon led with differing beam angles I believe there are 10, 25 and 30 degree angles available.

Quote:
Originally Posted by BarraCuda™ View Post
My view is very clear, by today's technology, there is no way 1watt LED can produce 170 lumens period.
You have insisted upon many facts in this thread which have been baseless or wildly inaccurate from the claimed 55 lumens for 3 watts maximum to the 1cm squared beam spread. Posting inaccurate and unsupported data is unhelpful to anyone.
 
Old 09-10-2006, 11:21 PM   #54
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Quote:
Originally Posted by aropal View Post
If you are looking at a light that is described in terms of its lumen output then you have no basis for making disparaging comments in terms of its lux.
Dont take my word for it. Ask the manufacturer for the lux rating. See if that particular light fixture is made for spot lumination.

Quote:
Originally Posted by aropal
The primary implementation of led lighting is that each element produces a small amount of light and then focuses it to a specific location. If you want more distributed light then you use more elements focussed on different areas.. If you want more intense light then you focus more elements on THE SAME area.
I agree with that. So you will need alot of narrow beam LEDs to luminate the entire tank right?

Quote:
Originally Posted by aropal
How is this relevant. All we care about is how many lumens are produced per watt.
Basic DC electrical theory tells you that Power(watt) = Voltage x Amperes
Assuming constant current, a higher voltage will give you higher wattage and a brighter bulb!

Quote:
Originally Posted by aropal
In terms of keeping fish, plants and invertebrates we might also reasonable be interested in CRI such that the action spectrum of our captive organisms are catered for.

[Incidentally, there are numerous bright LED manufacturers which claim a CRI in excess of 80; the only questions remaining are with regard to the location in the spectrum of that missing 20%]
CRI only tells you the difference between the colors viewed under sunlight and under the bulb. If the CRI is 100 then the color you look under the bulb will be 100% the same as you would have under the sun.

LEDs are not like FL or MH as it only have a very narrow spectrum. Ask for the spectrum chart of any single LED and you will see that the output will peak at a very narrow spectrum.

CRI = Color Rendering Index, nothing to do with spectrum quality needed for plants.
http://en.wikipedia.org/wiki/Color_rendering_index

What you should be looking at is Photosynthetically Usable Radiation (PUR) Plants typically require a peak at spectrum ~620-700nm for photosynthesis and other wavelength of light to survive. In order to create such a wide spectrum then multiple LEDs peaking at different wavelength would have to be mixed, look uniformed and pleasing to the eyes. Its easier said then done


Quote:
Originally Posted by aropal
The area covered is not 1cm x 1cm. Each of the three led elements is itself 1cm x 1cm. There are numerous brands of Luxeon led with differing beam angles I believe there are 10, 25 and 30 degree angles available.

You have insisted upon many facts in this thread which have been baseless or wildly inaccurate from the claimed 55 lumens for 3 watts maximum to the 1cm squared beam spread. Posting inaccurate and unsupported data is unhelpful to anyone.
I'm only stating an example for the 1000 lumens at 1cm X 1cm spot. It is to illustrate my point that its worthless to have such brightness when the area covered is just a small spot. You will need still alot of them to cover the entire tank.

Again dont take my words for it, ask the manufacturer for specifications. I can sum things up for you now.

No, 1 watt LEDs cannot produce 170 lumens as of today's technology.
High lumens LEDs are highly focused and not suitable for lighting wide areas.
Wide angle LEDs are dim and do not have power to penetrate deep tanks.
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Old 10-10-2006, 12:31 AM   #55
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Quote:
Originally Posted by BarraCuda™ View Post
Dont take my word for it. Ask the manufacturer for the lux rating. See if that particular light fixture is made for spot lumination.
.
I have various manufacturers data I have already asked them for. I have been posting manufacturer supported data for most of this thread.
Further and for your information lux is measured in lumens per square metre. If the beam is concentrated on a small area. Then the lux will be very high, this is how lux is measured. Focussed spot lights have a high lux rating.

Quote:
Originally Posted by BarraCuda™ View Post
I agree with that. So you will need alot of narrow beam LEDs to luminate the entire tank right?

High lumens LEDs are highly focused and not suitable for lighting wide areas.
These statements are mutually contradictory.
You need multiple led’s (something we have been saying from the beginning) due to each having a low total lumen output. If you have a large number of them to get the high lumen total you also have proportionally high coverage.

Quote:
Originally Posted by BarraCuda™ View Post
Basic DC electrical theory tells you that Power(watt) = Voltage x Amperes
Assuming constant current, a higher voltage will give you higher wattage and a brighter bulb!
These are not high voltage devices. Luxon’s LED’s are 4.5 volt (max).
Scaled up from your suggested 55, that would give 82.5 lumens not 135. Technology moves on!

Quote:
Originally Posted by BarraCuda™ View Post
CRI only tells you the difference between the colors viewed under sunlight and under the bulb. If the CRI is 100 then the color you look under the bulb will be 100% the same as you would have under the sun.

CRI = Color Rendering Index, nothing to do with spectrum quality needed for plants.
http://en.wikipedia.org/wiki/Color_rendering_index

What you should be looking at is Photosynthetically Usable Radiation (PUR) Plants typically require a peak at spectrum ~620-700nm for photosynthesis and other wavelength of light to survive.
CRI is the ability of a device to accutately render an object within the visible colour spectrum (as supplied by the sun); typically between 400 and 700nm.

http://www.topbulb.com/find/cri.asp

This includes the photosynthetic action spectrum for most green plants (which also use the sun), so if something has a CRI of 100% (or near it) it will naturally cover the action spectrum of plants.
[This is what I specifically questioned when I asked about the missing 80% of a lamp with a CRI of 80]

Quote:
Originally Posted by BarraCuda™ View Post

In order to create such a wide spectrum then multiple LEDs peaking at different wavelength would have to be mixed, look uniformed and pleasing to the eyes. Its easier said then done

LEDs are not like FL or MH as it only have a very narrow spectrum. Ask for the spectrum chart of any single LED and you will see that the output will peak at a very narrow spectrum.
It’s already done by Luxon. They have produced lamps with CRI’s of more than 90.
The CRI of the latest generation of LED lamps is 70 – 80 depending on the model.
Hardly what you’d call narrow band. If you doubt me go and contact them for yourself.

Quote:
Originally Posted by BarraCuda™ View Post
I'm only stating an example for the 1000 lumens at 1cm X 1cm spot. It is to illustrate my point that its worthless to have such brightness when the area covered is just a small spot.
It has a 25 or 30 degree beam spread, the size of the lighting element itself is hardly the issue. At the two feet depth this is not 1cm across. To increase the beam spread you use multiple beams, to increase the intensity you simply overlay multiple beams. (This may well be enough to penetrate greater depth although I have expressed scepticism about this myself.)

Quote:
Originally Posted by BarraCuda™ View Post
You will need still alot of them to cover the entire tank.
As we have been saying that from the beginning. Indeed the LED lamps offered are already of a multiple single LED configuration. The nature of LED lighing is that you have multiple relatively low output lamps to produce a large, more intense output.

Quote:
Originally Posted by BarraCuda™ View Post
No, 1 watt LEDs cannot produce 170 lumens as of today's technology.
Throughout this entire thread I have asked you to provide a source for this claim or any supporting evidence. I myself am highly sceptical of this specific claim by this specific manufacturer. I am happy to consider anything you have based your statement on for the good of providing a further education source for other forum members interested in this subject.

Last edited by aropal; 10-10-2006 at 12:45 AM.
 
Old 10-10-2006, 02:01 AM   #56
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Quote:
Originally Posted by aropal View Post
I have various manufacturers data I have already asked them for. I have been posting manufacturer supported data for most of this thread.
Further and for your information lux is measured in lumens per square metre. If the beam is concentrated on a small area. Then the lux will be very high, this is how lux is measured. Focussed spot lights have a high lux rating.
Please correct me if I'm wrong, lux is measured as lumens per meter square. Please kindly show me how a very bright spot will have high lux whereas the rest of the dark meter square area is outside the spot.

Quote:
Originally Posted by aropal
These are not high voltage devices. Luxon’s LED’s are 4.5 volt (max).
Scaled up from your suggested 55, that would give 82.5 lumens not 135. Technology moves on!
I checked the specs and 3.99V is the max forward voltage to be used.
Page 8 of http://www.luxeon.com/pdfs/DS23.pdf
I dont know where you got 135 lumens from but 55 lumens is for the LED that is driven at 3volts. Of course the bulb will be much brighter at 4V but you risk burning it if operated on its max value.

Quote:
Originally Posted by aropal
It’s already done by Luxon. They have produced lamps with CRI’s of more than 90.
The CRI of the latest generation of LED lamps is 70 – 80 depending on the model.
Hardly what you’d call narrow band. If you doubt me go and contact them for yourself.
http://www.luxeon.com/pdfs/DS23.pdf page 9, figure 1a
Look at the chart, most LED type peaked at a very narrow band

Quote:
Originally Posted by aropal
Throughout this entire thread I have asked you to provide a source for this claim or any supporting evidence. I myself am highly sceptical of this specific claim by this specific manufacturer. I am happy to consider anything you have based your statement on for the good of providing a further education source for other forum members interested in this subject.
I should be the one asking this question. The reason I entered this discussion is because I seriously doubt your claim of 170 lumens for 1 watt LED.
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Old 10-10-2006, 12:43 PM   #57
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Interesting & enriching discussions here on LED. Glad that there is strong faith that lighting efficiency can be better with LED in the future. With T5 fluorescent best at 92.5 lumens/watt (max), putting MH domimance to some challenge, it will be interesting break-thru if LED can ever produce 170 lumen/watt in the near future.
Of course, right now, my primary concern is how much of what type of lighting will breed nice enough looking red. In the past, I got 4 PL 55W blasting 16 hours a day, now I only running a 54W T5 daylight for my 4'/5' tanks. No side tanning, & Nan/TFC swtich on only during viewing or photo taking. Factors in consideration include light cost, operation cost, & maintenance need. A reliable brand T5 fluorescent is expected to last up to 24,000 hours. As for choice, I will go for commercial Osram, Philips or GE, etc, it is really quite affordable if one can diy a little. I retrofit T5 (tube & electronic ballast) into one of the Big Boy (come with two T8 tubes). Clean & need, & for those that want more brightness, think a Big Boy can easliy hold 4 x 54W T5. That's cool power right?
 
Old 10-10-2006, 07:37 PM   #58
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Quote:
Originally Posted by BarraCuda™ View Post
Please correct me if I'm wrong, lux is measured as lumens per meter square. Please kindly show me how a very bright spot will have high lux whereas the rest of the dark meter square area is outside the spot.
You’re wrong. Lux might reasonably be considered a measure of brightness not one of distribution. A lux reading is taken at a single point in the illuminated area and then the total light given in units involving square metres. So, if you want a higher lux value you simply focus your total lumens on a smaller area. Of course this means when considering areas less than 1 square metre it can provide rather curious results. This is another reason why lux is meaningless when being used to calculate total coverage.

Quote:
Originally Posted by BarraCuda™ View Post
I checked the specs and 3.99V is the max forward voltage to be used.
Page 8 of http://www.luxeon.com/pdfs/DS23.pdf
I dont know where you got 135 lumens from but 55 lumens is for the LED that is driven at 3volts. Of course the bulb will be much brighter at 4V but you risk burning it if operated on its max value.
We don’t care what voltage you drive the led at. All we are interested in is how many lumens per watt and how many hours it will run.
I gave a link to the place where the reseller stated that the luxon star led lamp produced 135 lumens. I’ll give it again:
http://www.ultraleds.co.uk/product_i...b532838ed5c169

Quote:
Originally Posted by BarraCuda™ View Post
http://www.luxeon.com/pdfs/DS23.pdf page 9, figure 1a
Look at the chart, most LED type peaked at a very narrow band
That is because that particular page shows leds specifically engineered to have narrow bands. The page shows specific data for green, cyan, royal blue, red orange, amber AND WHITE. The coloured led’s are quite obviously narrow band. That is why they are specific colours. The white led’s are not. They can be engineered to have a spectrum covering between 400 and 700nm.

Quote:
Originally Posted by BarraCuda™ View Post
I should be the one asking this question. The reason I entered this discussion is because I seriously doubt your claim of 170 lumens for 1 watt LED.
You should indeed be asking the questions. You are described as a senior moderator on this forum and as such you opinion is valued. Thus, it is particularly unhelpful when you present as fact unsupported or misinterpreted information. Your statement that I have claimed it is possible to produce 170 lumens for 1 watt is point in fact.
I have stated from the beginning that 10 lumens per watt is the typical incandescent output and that if the reseller claims a LED produces 17watts of incandescent light it should be equivalent to 170 lumens if true; a fact which I have continually expressed scepticism about.

Further, the light I have bought is not Luxeon. Again, as stated from the beginning the light I have bought to test has a “claimed by the reseller” light output of 17 incandescent watts. This should be 170 lumens but since the same reseller states that 20 watts is 135 lumens on the Luxeon link, this should mean my test lamp produces 114 lumens. Of course the reseller insists this is for 1 watt but this can easily be tested by confirming the current used when running. My guess would be that the reseller made a type-O and this is 114 lumens for 3 watts still a great deal more than the value you previously insisted as being the maximum of 55 lumens for 3 watts.
 
Old 10-10-2006, 10:30 PM   #59
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Quote:
Originally Posted by aropal View Post
We don’t care what voltage you drive the led at. All we are interested in is how many lumens per watt and how many hours it will run.
I gave a link to the place where the reseller stated that the luxon star led lamp produced 135 lumens. I’ll give it again:
http://www.ultraleds.co.uk/product_i...b532838ed5c169
If you dont know the voltage then how do you know the wattage? The formula is given to you. Wattage = Voltage X Ampere
The higher the voltage, the brighter the LED. Grab an LED, connect it to 1.5V then connect it to 3V, tell me if the LED is brighter at 3V.

You grab a 3W LED and apply 1.5V, it will light up but it will be dim. Now apply 4V and the LED will be very bright. The voltage directly determine the total amount of power the LED will use.

If you apply 3V to a 3W LED that have a max of 4V then technically you are not driving the LED at its max value of 3W. The manufacturer will always give you the max value possible but is it practical to run at the max 4V?

The product posted is 3x 1watt LED, its different from a single 3watt LED. Can a person with 6 hands do the job of 3 normal man?

Quote:
Originally Posted by aropal
That is because that particular page shows leds specifically engineered to have narrow bands. The page shows specific data for green, cyan, royal blue, red orange, amber AND WHITE. The coloured led’s are quite obviously narrow band. That is why they are specific colours. The white led’s are not. They can be engineered to have a spectrum covering between 400 and 700nm.

You should indeed be asking the questions. You are described as a senior moderator on this forum and as such you opinion is valued. Thus, it is particularly unhelpful when you present as fact unsupported or misinterpreted information. Your statement that I have claimed it is possible to produce 170 lumens for 1 watt is point in fact.
I have stated from the beginning that 10 lumens per watt is the typical incandescent output and that if the reseller claims a LED produces 17watts of incandescent light it should be equivalent to 170 lumens if true; a fact which I have continually expressed scepticism about.

Further, the light I have bought is not Luxeon. Again, as stated from the beginning the light I have bought to test has a “claimed by the reseller” light output of 17 incandescent watts. This should be 170 lumens but since the same reseller states that 20 watts is 135 lumens on the Luxeon link, this should mean my test lamp produces 114 lumens. Of course the reseller insists this is for 1 watt but this can easily be tested by confirming the current used when running. My guess would be that the reseller made a type-O and this is 114 lumens for 3 watts still a great deal more than the value you previously insisted as being the maximum of 55 lumens for 3 watts.
My answer is above.
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Old 10-10-2006, 10:54 PM   #60
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Originally Posted by BarraCuda™ View Post
If you dont know the voltage then how do you know the wattage? The formula is given to you. Wattage = Voltage X Ampere
The higher the voltage, the brighter the LED. Grab an LED, connect it to 1.5V then connect it to 3V, tell me if the LED is brighter at 3V.
You grab a 3W LED and apply 1.5V, it will light up but it will be dim. Now apply 4V and the LED will be very bright. The voltage directly determine the total amount of power the LED will use.
If you apply 3V to a 3W LED that have a max of 4V then technically you are not driving the LED at its max value of 3W. The manufacturer will always give you the max value possible but is it practical to run at the max 4V?
The product posted is 3x 1watt LED, its different from a single 3watt LED. Can a person with 6 hands do the job of 3 normal man?
I’m perfectly aware of the methods to calculate power. This is within my field of work.

Firstly, we don’t need to work out the wattage as the manufacturer supplies the data.
Secondly, the output difference shows no relation to voltage for the baseless and dated 55 lumen figure that your repeatedly state.
 
 


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