# Lumen Maintenance in the Retrofit Business



## Cletis (Aug 20, 2010)

*L.M.*

I'm seeing different numbers? All the independent charts I just looked at 
were 70-90k hours at 70% lumen depreciation for induction and LED at about 50k for 70%. 

I'll try to find some more links and post later. 

Cletis


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## LightsRus (Sep 12, 2010)

*Re: L.M.*



Cletis said:


> I'm seeing different numbers? All the independent charts I just looked at
> were 70-90k hours at 70% lumen depreciation for induction and LED at about 50k for 70%.
> 
> I'll try to find some more links and post later.
> ...


Thanks for that. 
The Induction graph I posted previously does actually cross through 70% at 60K hours.
The mystery is that vendors say it's a 100,000 hour light, but what does that really mean? I don't believe any Induction manufacturer has actual 100K Hr burn time on these products, if they did, the data would be more forthcoming. 
Lumileds does have real 50,000+ hour data on the Luxeon Rebel. 

Finding lumen maintenance figures for Induction Lighting is quite a challenge. It must be a secret.

I've gone a bit farther with data gathering and comparison here:








This is very important stuff to know when luminance is actually important, and you need to meet standards at 100,000 hours.


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## Cletis (Aug 20, 2010)

*Led*

Nice charts. Keep them coming. I agree, there is a lot of conflicting info. I'm looking around for some historical data on inductions. If I find I will post. Here is something interesting. The military just banned LED's 

http://www.edisonreport.net/Articles/Army-Air Force LED req 3-30-10.pdf

Didn't have time to read article but it looks like they are banning them in all their facilities inside and out. 

Cletis


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## LightsRus (Sep 12, 2010)

*Re: Led*



Cletis said:


> Nice charts. Keep them coming. I agree, there is a lot of conflicting info. I'm looking around for some historical data on inductions. If I find I will post. Here is something interesting. The military just banned LED's
> 
> http://www.edisonreport.net/Articles/Army-Air%20Force%20LED%20req%203-30-10.pdf
> 
> ...


Not exactly banned. They are tightening the rules. 
To start, every exterior project will be certified (11.1.1) by an experienced registered professional engineer with background in lighting design. 
That is good.
Everything will be specified to some IESNA standard and have LM-79 and LM-80 testing to back it.

I believe they are cracking down on the junk, imported or otherwise, that have cut sheets and marketing with totally bogus (non verified) claims.


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## Electric_Light (Apr 6, 2010)

Decay is contingent on drive current, air temperature and junction temperature. Efficacy is contingent on drive current and junction temperature. 

Here is a prediction on CREE Xlamp XR-E, in a presentation published in 2009.

http://www.cree.com/products/pdf/XLampXR-E_lumen_maintenance.pdf

I picked out a graph with ambient 45C, which is probably about right for inside a fixture that operates after sunset. Lower drive current means lower output per LED, so more LEDs must be used which means higher initial cost. Perhaps 75



LightsRus said:


> IESNA lighting standards can define when to replace the light, if adhered to. However, sometimes a leased streetlight isn't replaced as long as it will glow.


Maybe so, but using something that doesn't have to build-in accommodation for 30% depreciation which requires over spec'ing by 42.8%. If initial x 0.7 x 1.428 is the target, as I mentioned before, you can get away with lower initial lumen fixture and consequently lower power input since the depreciation allowance doesn't need to be made as large.

Perhaps 75C air temp is more appropriate because the encapsulating resin will decay in transparency with exposure to high temperatures during the day as well as sunlight. In Phoenix AZ, 75C inside a sunbaked street light isn't out of question.


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## Electric_Light (Apr 6, 2010)

LightsRus said:


> Not exactly banned. They are tightening the rules.
> To start, every exterior project will be certified (11.1.1) by an experienced registered professional engineer with background in lighting design.
> That is good.
> Everything will be specified to some IESNA standard and have LM-79 and LM-80 testing to back it.
> ...



"8.6. Retrofit conversion of LED lamps or LED lighting module inserts that have been
designed and constructed to be used in existing high-intensity discharge (HID)
luminaires—including metal halide, mercury vapor, or fluorescent fixture
enclosures—are prohibited. New, complete-assembly LED luminaires shall be used"


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## Lighting Retro (Aug 1, 2009)

I would venture to say that the two products you mentioned are ones not used a majority of the time in retrofits, and partially due to this reason. 

The only place we have installed induction is where the cost of servicing the fixture is outrageous. Some depreciation is fine in that scenario, but part of the selling point against HID is depreciation. Doesn't do you much good if you put in something similar IMHO. 

The newest and best T8 lamps used most often in retrofits by us are now claiming 95% lumen maintenance over the life of the lamp. When that is 42,000 hours in some cases, it can be pretty difficult to justify LED or induction unless it's a specific application where linear just isn't a fit. 

I would use them all day to replace incandescent, and in some cases a like for like replacement on HID would make sense. It certainly would not be worse than what is currently in the facility. I personally just cannot stand having a new lamp next to a depreciated one and having a MAJOR difference in output. Just bugs me.


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## Electric_Light (Apr 6, 2010)

Lighting Retro said:


> I would venture to say that the two products you mentioned are ones not used a majority of the time in retrofits, and partially due to this reason.
> 
> The only place we have installed induction is where the cost of servicing the fixture is outrageous. Some depreciation is fine in that scenario, but part of the selling point against HID is depreciation. Doesn't do you much good if you put in something similar IMHO.


Those low-frequency square wave driven ceramic metal halide looks promising compared to induction as far as depreciation, but the life is limited to 24-30K before failure. 

The newest and best T8 lamps used most often in retrofits by us are now claiming 95% lumen maintenance over the life of the lamp. When that is 42,000 hours in some cases, it can be pretty difficult to justify LED or induction unless it's a specific application where linear just isn't a fit. 



> I would use them all day to replace incandescent, and in some cases a like for like replacement on HID would make sense. It certainly would not be worse than what is currently in the facility. I personally just cannot stand having a new lamp next to a depreciated one and having a MAJOR difference in output. Just bugs me.


The good old 4' tubes are the way to go for offices, government and school and more recently homes, but they're really sensitive to heat, as you know. 

normal linear lamps are not for outdoors. You could put a jacket on them in the winter, but they'll get too hot in the summer and suffer reduced efficacy. 


Now for LEDs, I can attest that ":" that separates the hours and minutes have not failed after 52,000 hrs + in actual service. the upper and lower dot that indicates AM or PM are still fine after 26,000 hours too. None of the segments failed either. Are they as bright as the day I bought it? I have no idea.


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## Lighting Retro (Aug 1, 2009)

There are also some digital ballasts and new metal halides coming that are not supposed to experience the same lumen depreciation. 

I believe Mpower and Accenture are the two I've been exposed to. There are limits to applications like anything else, but not too bad.


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## Electric_Light (Apr 6, 2010)

Lighting Retro said:


> There are also some *digital ballasts* and new metal halides coming that are not supposed to experience the same lumen depreciation.
> 
> I believe Mpower and Accenture are the two I've been exposed to. There are limits to applications like anything else, but not too bad.


I don't remember the brand, but there are some compact MH designed for use only with a matching ballast, not a standard ANSI ballast. "digital ballast" is just a marketing ploy, like digital headphones that plug into standard headphone socket. 

Apparently, acoustic resonance can happen at high frequency and destroy HID capsule, so a common way of driving HIDs with an electronic ballast is low frequency (<500Hz) squarewave. Square wave has a crest factor of 1.0, which I believe is responsible for reduction in lamp decay. (crest factor is peak current over RMS current, its 1.0 for square wave, 1.41 for sinewave and it can be above 1.41 with series capacitor) 

I believe the Philips 320W ceramic metal halide still lose 15-25% over lifetime, which is better than 40% or so of traditional MH.


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## LightsRus (Sep 12, 2010)

Electric_Light said:


> Maybe so, but using something that doesn't have to build-in accommodation for 30% depreciation which requires over spec'ing by 42.8%. If initial x 0.7 x 1.428 is the target, as I mentioned before, you can get away with lower initial lumen fixture and consequently lower power input since the depreciation allowance doesn't need to be made as large.
> 
> Perhaps 75C air temp is more appropriate because the encapsulating resin will decay in transparency with exposure to high temperatures during the day as well as sunlight. In Phoenix AZ, 75C inside a sunbaked street light isn't out of question.


There is a segment of us in agreement that diminishing output by 30% is too much. That was the point of this thread, what is it worth to flatten that characteristic? We will all notice that darker lamp, especially within a mixed group of old and new.

There is a segment out there that is perfectly happy with 100,000 hours to burn-out. They don't care, or don't understand the reduced light output. It depends on the application.
_
Not sure what you mean by 'decay in transparency with high temperatures' as that would suggest temperatures far greater than any found in a fixture (unless maybe it's on fire?). _

Bottom line is that any light source output level will diminish over hours of use. The original question is basically how to deal with the cost to remedy. Will we:
1) over-size lamp to allow the dip and remain in spec? or 
2) replace early in the life cycle to ensure spec? or 
3) use product with better lumen maintenance? 
It seems a matter of where you put the money, so, which is easier for a customer to accept? (Remember, some only need for the light to glow and don't care if that light is usable.)


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## Electric_Light (Apr 6, 2010)

LightsRus said:


> There is a segment of us in agreement that diminishing output by 30% is too much. That was the point of this thread, what is it worth to flatten that characteristic? We will all notice that darker lamp, especially within a mixed group of old and new.


So its about aesthetics with no regard to performance consideration and how far you stretch your BS regarding your performance, or lack thereof?



> There is a segment out there that is perfectly happy with 100,000 hours to burn-out. *They don't care, or don't understand* the reduced light output. It depends on the application.


so, I take it your business model is to exploit your customers' lack of knowledge to sell overpriced garbage? 



> _ Not sure what you mean by 'decay in transparency with high temperatures' as that would suggest temperatures far greater than any found in a fixture (unless maybe it's on fire?). _


I cited my reference for the graph, with a publicly viewable PDF no less. It helps to do your reading. Since you found yourself unable/unwilling to do so, here are some quotes from it:

"However, Cree has observed that high ambient air temperatures also play an important role in the longterm
lumen maintenance of silicone-encapsulated LED lamps.
As an example, the graph above shows the lumen maintenance results

Most high power LED lamps, including XLamp LED
lamps, use silicone materials in the package. When exposed to high
temperatures these silicone materials will degrade, reducing the light
that is transmitted through them from the LED chip"




> Bottom line is that any light source output level will diminish over hours of use. The original question is basically how to deal with the cost to remedy. Will we:
> 1) over-size lamp to allow the dip and remain in spec? or
> 2) replace early in the life cycle to ensure spec? or
> 3) use product with better lumen maintenance?
> It seems a matter of where you put the money, so, which is easier for a customer to accept? (Remember, some only need for the light to glow and don't care if that light is usable.)


4) Once its determined that LEDs high depreciation rate of 30% is acceptable and you choose #3, you can actually use LOWER wattage product, or reduce the number lamps, depending on applications. So if we had just for comparison, a zero depreciating source (well, LPS is more or less zero depreciation, but its monochromatic), then it can start with 70% the LED's initial level. If the efficacies are comparable, that's 30% energy savings right there.

Philips Lumileds Luxeon Rebel you use to construct your light module doesn't have exactly impressive efficacy. What is the power input to actual output efficacy at stabilized normal working temperatures (that means not as soon as it comes on, but after it is allowed to heat up until it no longer heats up any further)?


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## Lighting Retro (Aug 1, 2009)

Have you guys ever spec'd out Compact Metal Halides for Can lights? Just starting to see some of that, and the output via spec sheet is pretty impressive.


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## LightsRus (Sep 12, 2010)

Electric_Light said:


> "However, Cree has observed that high ambient air temperatures also play an important role in the longterm
> lumen maintenance of silicone-encapsulated LED lamps.


Luxeon specifically addresses this in the LM-80 data for the Rebel LED, and they found this to be negligible.

In that CREE, the mean of this effect is actually only about 2%, and it appears to be even less as time goes on.



> Philips Lumileds Luxeon Rebel you use to construct your light module doesn't have exactly impressive efficacy. What is the power input to actual output efficacy at stabilized normal working temperatures (that means not as soon as it comes on, but after it is allowed to heat up until it no longer heats up any further)?


I've designed and shipped hundreds of product with many different families of CREE, of Luxeon and of others. Each have their qualities, good and bad; those things that we work with or around.
You have lots, and lots more reading ahead in order to catch up with that technology. Try not to get bogged down withhttp://www.answers.com/topic/minutia minutia.


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## Electric_Light (Apr 6, 2010)

LightsRus said:


> I've designed and shipped hundreds of product with many different families of CREE, of Luxeon and of others. Each have their qualities, good and bad; those things that we work with or around.
> You have lots, and lots more reading ahead in order to catch up with that technology. Try not to get bogged down with minutia.


Perhaps you didn't understand my question. I was asking what your system efficacy is at stabilized operating temperature in lm/W. IESNA does not recognize the use of "scotopic" crap LED sales people often use. This means photopic lumen output measured with LED assembly at temperature seen in actual use, divided by full power consumption including driver loss. 

I didn't ask about your subjective qualities. I asked for a number as it relates to the thing you're selling.


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## LightsRus (Sep 12, 2010)

Electric_Light said:


> I was asking what your system efficacy is at stabilized operating temperature in lm/W. IESNA does not recognize the use of "scotopic" crap LED sales people often use. This means photopic lumen output measured with LED assembly at temperature seen in actual use, divided by full power consumption including driver loss.


Couldn't find the reference to _"scotopic"_ in this thread. Maybe I missed it.

I've seen it used several different ways, so am not sure how _"scotopic"_ fits into that math without seeing how it was used, or how you are using it. There must be more to that statement.


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## Electric_Light (Apr 6, 2010)

LightsRus said:


> Couldn't find the reference to _"scotopic"_ in this thread. Maybe I missed it.
> 
> I've seen it used several different ways, so am not sure how _"scotopic"_ fits into that math without seeing how it was used, or how you are using it. There must be more to that statement.


You mentioned it in a different thread. It was/is a common marketing scam used by LED cram-in retrofit in order to make their poor performance comparable with lower CCT source their products are replacing.

Industry standard is photopic lumens. Foot candle values, lumen values in catalog, etc are all based on photopic. LED sales people and Lights of America are known to use scotopic. Lights of America 6500K CFL outdoor lights at one point used scotopic lumens in its packaging.

Some LED vendors compare their 6500K LED scotopic(which is like 250% of its photopic) to HPS scotopic (which is like 80% of its photopic) to make their products look like its three times more efficient.


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## LightsRus (Sep 12, 2010)

Electric_Light said:


> You mentioned it in a different thread. It was/is a common marketing scam used by LED cram-in retrofit in order to make their poor performance comparable with lower CCT source their products are replacing.


Correct, I did not mention that in this thread. In that _other_ thread, I believe it was to question "Scotopic" advantage. 



> Industry standard is photopic lumens. Foot candle values, lumen values in catalog, etc are all based on photopic. LED sales people and Lights of America are known to use scotopic. Lights of America 6500K CFL outdoor lights at one point used scotopic lumens in its packaging.
> 
> Some LED vendors compare their 6500K LED scotopic(which is like 250% of its photopic) to HPS scotopic (which is like 80% of its photopic) to make their products look like its three times more efficient.


There are plenty of brand name companies jumping on that. One example is this link http://www.sylvania.com/BusinessProducts/InnovationGallery/Post+Top/ claiming 80% energy savings for lighting. Such a claim is only possible by reducing the lighting requirement.

It brings into question the actual training or education in lighting of many LED sales people. Some think that because LED traffic signals saved over 80% in energy, they can make that claim in illumination. That has given the LED sales effort a black eye. 

Now, the Induction Lighting sales effort is trying the same thing with "Pupil Lumens" which is a phrase coined by PhD's that knew what it meant. The scientists meant well, but good information fell into the wrong hands.

The damage comes from believing the hype, and without doing a real lighting layout, they just buy and install lighting product that can't do the job. Who will pay to correct the mess?
*
But the topic is lumen maintenance, and how to actually define and handle end of life.*


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## Electric_Light (Apr 6, 2010)

LightsRus said:


> *
> But the topic is lumen maintenance, and how to actually define and handle end of life.*


Lumen maintenance is just another way of saying resistance to lumen depreciation and for lamps that do not fully burn out, thats what marks the cut off point for no longer useful. So it's fully relevant.


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