Anyone ever wanted to use led as source for LL pj?
Check this out!

http://fullcoverage.yahoo.com/s/nm/tech_ph..._streetlamps_dc

this is actually old news for us in Adelaide, Australia. We have LED street lights and were the official test for this company.. they work really well and i hear the power is WAY WAY down and brightness is actually higher..

We started getting them about 2 years ago, just about our whole city has them now, minus a few.

What a crap idea!

LEDs are WAY less efficient than the usual HPS lamps, and I've heard loads of astronomers complaining about the full spectrum light they give out, which "lights up the skies" white instead of narrow-band orange (which is apparently easy to remove).

The streetlamps are also more expensive, and the longer time between replacement isnt enough to make them financially viable against HPS streetlamps, which are far more efficient devices.

In this case it makes one wonder why they adopted them. However when one considers that the bulbs in HPS streetlamps would need to be replaced 4 times as often, even if the bulbs are twice the cost I can see the savings on parts and labor being rather considerable.

HPS (conversion bulbs) is (are) more viable for our projectors.

Also, HPS fades in brightness over time, something I'm not sure LEDs do...

(Things in parentheses were edited to improve readability)

I agree with it being a bad idea for street lamps. I'm glad we still have HPS with it's narrow band emission around here. Especially with the fog we had this morning. That's the dumbest idea I've heard from Philip's. It'd be a waste of taxes.
It currently can't beat HPS in cost and efficiency in street lamps.

As far as LEDs in projection, I think it's an excellent idea for DLP DMD projectors. It has a longer life compared to the short arc metal halide (using RGB LEDs instead of a color wheel decreasing it's duty cycle will make them last even longer), is more optically efficient, and is at a cost comparable to short arc MH's. LEDs still have a long way to go to compete with the lamps we use in DIY LCD projectors though.



LEDs are far more than twice the cost of HPS currently. It's more like over a hundred times comparably. HPS has a long enough lifetime that there would be little difference in labor costs compared to LEDs. Actually I think it would end up costing more to group relamp $1K+ LEDs every 16 years compared to $20 +/- every 4 years with HPS. Oh yeah forgot to add that LED's do fade although it ramps down compared to the curve of HPS.

Entropy Project, I'm afraid you are incorrect on two counts.

HPS is totally unsuitable for our projectors, since its very narrow band.
LEDs do lose brightness over time. Thats why they need to be replaced.

Hyper Smiley, I completely agree with you!

HPS is viable for our projectors I am using a HPS conversion bulb in mine.

I agree with you that the HPS bulbs from the streetlamps, would not be suitable.

If you'd bothered to read the article linked to in the first post of this thread, you'll note that the life expectancy of the LED lamps is quoted at 50,000 hours compared to the 12,000 hours for the HPS bulbs. The led lamps are twice the price. Hence, a 50% overall savings, before labor is figured in.

I also stated that I was uncertain if LEDs faded over time, and only stated that I knew that HPS bulbs did.

(Edit: I see where I switched between subjects twice in three sentences, and caused the confusion. I will remedy this promptly.)

can you tell us what lamp are you using? I doubt it is a HPS one. (HPS conversion referes to a MH white bulb replacement instead of a HPS yellowish one, maybe it is what confused you)



edit: mm, i think i understood it other way, it looks like it is a HPS lamp to by driven by MH driver. Anyway, can you link us to your bulb?

I am using the Ushio S400DD, the same one sold in the LL store.

https://secure.lumenlab.com/shop/group.php?id=4

It is a MH bulb designed to work with a HPS ballast, or the Lumenlab Eballast, hence the "conversion " or "retrofit" monniker

(I'm gonna really feel foolish if I mucked up the terminology)

mm, that's what I thought. It is not a HPS lamp but a MH (metal halide)

the HPS lamps are unusable for us because of their color and their arc lengh (sometimes). Here the MH lamps are typically designed to work on HPS gears (so conversion takes sense here...). The yellow lamps of the street are typically HPS. they are the most effective ones, but we need daylight (white light).

Rox you are correct. Entropy project, you are sadly incorrect.

NO offense to those that believe this is a bad idea .... but look at the facts ...

An LED will fade, but it fades at a much later point in its life ..... Not a half life that is typical in many bulbs ...... an LED will have intial brightness at 75%-80% life, only towards the end will it begin to fade.

Compare that to HPS/MH lamps that begin to fade at a much earlier point, that ups the replacement frequency.

Labor cost are probably quite a significant chunk, so that save in labor of only having to change the bulbs 1/2 as often probably make up an even more financial defecit. Oddly though, It may result in the loss of a job for someone that works for the city changing bulbs ..... but ... thats all relative ...

I work for a company that designs/builds railway and subway electronics and control systems. We use HID LED's inside the railway crossing lights, where as in the past they used to bulbs as well. They are more effecient, and last a guesstimated 8 times longer than the bulbs previously used.

Lastly, I would have to think that all the engineers at Phillips, with the city, and anywhere else could be wrong, while a few people on a DIY projector site are correct. I believe this is a great Idea.

well, can you tell us the efficiency on them?

May I inquire as to how? It seems that Rox and I were discussing the same thing simply using different terminology. He is referring to the S400DD as a MH bulb due to the spectrum it puts out and the gasses involved in it's lumenescence. I am referring to it as a HPS (conversion) bulb because of the ballast required to operate it.

Both of us are correct.

Your comment of



fails to explain exactly what you are referring to.

If I have made a factual error somewhere, pray tell me what it is and I will either admit my mistake, or explain my reasoning. I believe I have explained my reasoning in regards to the efficacy of LED based street lamps, and I clarified my point in regards to what I was referring to when I mentioned HPS in my comment above.

mm let's calm...

that is wrong!!, or you are wrong!.. Or I never am wrong!... What the hell does it matter?? we are here to learn things, so we need to discuss things...

as i see (here for instance http://www.discount-hydro.com/lightbulbs.asp) HPS conversion bulbs are HPS lamps that work on MH gears. And MH conversion bulbs are those MH lamps that work on HPS gears... well, you can tell lolita to a MH lamp and i will understand what you mean if you first tell me what do you define as lolita of course .


Now i still don´t know the efficiency on the leds, can anyone trhow an input or a link... thanks.

No, I dont know off the head .... .Im not the type of person that is big on specs, cause most of it is garbage anyway ....

here is why they were more effecient for OUR use .....

The lamps that were used before the LEDs in the railway lights had to have a lense in front of them that made the light red, this lense filtered out alot of its output. With the LEDS that lense is no longer used, cause the LEDs themselves emitt the red color.

Also you have to consider that with a bulb alot of light is wasted being sent out the wrong direction, even when you use a reflector there is light loss, with an LED you can control the direction of the light much more effeciently, with less light loss.

So while the best LED's Ive read about months ago, could only do about 800 lm/watt their practicality can make up for it.

for example, our projectors .... granted we cant use them yet, because we cant condense the light properly but .... assuming we can think about ....

With a reflector our large MH bulbs, lose a considerable amount of light ..... and our brightest lamps that we use are 40,000 intial lumens. thats 100 lumens/watt ..... Now lets say we can make an LED array work, that is 800 lumens/watt ...... With the design and the lessened light loss we could potentially control the light better and in fact harness more light from the LEDs that we can an MH lamp.

Again, I know we cant used an LED array just yet, I was just using that as an example to look beyound the piece of paper that lists the Lumen/watt specs.

Just as in my companies case ... .The LED's were much more effecient, we got more light with about the same power, and plus the replacement value of only having to replace the LEDs 1/8 as often as the lamps .....

It really boils down to the application ....

Give me that led, I will pay you all you ask for it .

Please check that spec with time in calm... I think you estimeted it very far from it's real spec.

an LED array that produced that .... yes its true, I read about it somewhere several months ago .....

but again .... why do the numbers mean everything ... read the rest of my post ....

Ill see if I can find the page again.

I was mistaken on my math though ...... a MH lamp is around 100 lumens/watt ... Not 1000 ..... so that would make the article I read claimed aobut 75-80 lumens/watt from the LED array ......

All I remember is that it was about 75-80% effecient as our MH's ...... but setting that aside, it again boils down to the application ....

for example we were able to harness more light output with our crossing lights. There was no filter lense, therefor we were able to switch to the LED, while it didnt produce as many lumens/watt ... we didnt need as many lumens .....

in the end, we got as much light, with less power, and much cheaper replacement cost ....

It is a fact that LED's need to be replaced alot less often, after you add that, and the fact that with the more controlled environment that needs less lumens, then in the end it can be more efficient to your wallet ....

Get out of the spec world. I remember you being heavily worried about commercial ANSI lumens, versus our DIY lumens ...... and when brain posted the results, you still were satisfied and tried finding ways to measure Peak lumens in a DIY PJ ....

You gotta live outside the numbers, and think more about the application .... I listed above a two quite clear examples of how LEDs are more effecient ... sure in some cases a bulb will be the better choice ..... but not always ..... In the end, there are thousands of factors other than the simple Lumen/watt rating ....

Wow wow wow.. didnt mean to offend anyone!

Entropy Project and Rox, I apoligise for not making myself clear.
What I was trying to explain, and failing miserably, was the following.

HPS Are Not Suitable For Projectors.

HPS Conversion lamps are NOT HPS lamps. Do not let anyone fool you into thinking otherwise. They are MH lamps designed to run on HPS gear. This includes the S400D.

scubasteve, I totally agree with you that LEDs are more efficient for your purposes, but I hold my opinion that they are considerably less efficient than HPS streetlamps. If anyone wishes to argue this, Please do so!

I was wrong, what I had been referring to as HPS (conversion) bulbs should have been referred to as MH (conversion) bulbs.

Thank you for correcting me in this matter.

mmm, ANSI lumens.. thats a spine i have yet... would like to discus it with any interested in though .

about your superleds, what if i tell you that you won´t find leds with efficiency higher than 50lm/watt? (and I have inflated a bit this value in your direction).

When the leds did substitute the brakes lights on cars, it is because it works longer and it is MORE EFFICIENT THAN HALOGENS, but our MH are very efficient lamps that you hardly will improve with leds.

I believe the most efficient lamp techonoly is the HPS one, with up to 130 lumnes/watt.

it looks like being wrong is unaceptable for some people .

Apology accepted. A bit unnecessary (see my above post) but accepted nonetheless.

The reasoning (numbers, etc.) that I utilized was pulled from the article linked to in the first post of the thread. While a led based solution may be less efficient, it seems that as an overall solution, it is cheaper. (Hence less efficient, but more efficacious.)

I agree with you: the HPS bulbs utilized in the streetlamps would not be suitable for our purposes.

Again I say .... it was an LED array, maybe there was some time of reflector, or other device that intesified the light ..... it was NOT LED's by themselves ....

None the matter, some people are just toooo hung up on numbers, when you need to start thinking of effeciency in terms of more than just electricity through a lighting element ....

How many Lumens/watt is totally irrelevant when the less effecient component can be harnessed more effeciently .....

Just like a commercial projector that uses a substiantlly lower wattage bulb, but yet is brighter ......

You gotta think outside the box, who cares what the numbers say on paper, what matters is how its used.

Again, im no street lamp guru ... but if Phillips is making these things, its for a reason .... their engineers and the city engineers are just using them because they are bored, there has to be an advantage, and it has to be obviously be cheaper in the long run .....

an MH bulb sends light in all directions, you cannot control this ..... adding a reflector will aid in the direction you intend the light to go. and LED is much more directional, it can be aimed better and light can be collected easier ....

so ........ which is really more effecient .... in MH lamp at 100lumen/watt that ends up with half of its light wasted.... or an LED at 50lumens/watt that has most of its light used ...... If you needed a 20,000 lumen output, with a bulb you would probably have to choose something twice that in order to achieve your goal .... with a proper LED array you wouldnt have to go up so far .......

"None the matter, some people are just toooo hung up on numbers, when you need to start thinking of effeciency in terms of more than just electricity through a lighting element ....

How many Lumens/watt is totally irrelevant when the less effecient component can be harnessed more effeciently .....

Just like a commercial projector that uses a substiantlly lower wattage bulb, but yet is brighter ...... "

Well, thats what i learned as efficiency (desired output/consumition) higher efficiency means les power for same output. (by the way, a leds array will have the same efficiency... than each single led)

"an MH bulb sends light in all directions, you cannot control this ..... adding a reflector will aid in the direction you intend the light to go. and LED is much more directional, it can be aimed better and light can be collected easier ...."

mm, there are MH bulbs as well with included reflectors, do you consider them more efficient just for having a reflector?

"so ........ which is really more effecient .... in MH lamp at 100lumen/watt that ends up with half of its light wasted.... or an LED at 50lumens/watt that has most of its light used ...... If you needed a 20,000 lumen output, with a bulb you would probably have to choose something twice that in order to achieve your goal .... with a proper LED array you wouldnt have to go up so far ......."

It is very easy, it will be more efficient the one that consumes less power to obtain the same output. (I believe MH until you prove i am wrong that i don´t reject thisposibility )

Your problems are solved. Here is my design for a high efficiency LCD projector. And a patent is pending on this design.

DJ

mmm, patentpending you said...

lets call it lumenlab pro setup 2. There is cigarete starter included in the design... that's really pro

Perhaps you would like to elaborate on the so called "High Efficiency Plasma Array"?

I have never heard of one of them before.

I still think it's currently a bad idea mostly due to the cost involved. LED's can compete with incandescents but currently can't compete fully with HID lighting. Industrial HPS is too cheap comparatively. LEDs can compete with incandescents, lamps in DLP projectors due to cost, and possibly HID headlights, but not HPS streetlamps. You can't really compare railroad signaling that used incandescents to streetlamps that use HID.

At current productions of LED's at 60lm/w and 5 cents per lumen and a projection of 80lm/watt at the end of this year it can happen in the future, but not now. Then it'll probably be another decade for it to become mainstream. Look how long it's taking for incandescents to become obsolete. Only incandescents in my home is in the major appliances.

I've always had a high amount of respect for Phillips. They have great engineers and quality control, but we know they've made bad business decisions in the past. HPS streetlamps should be last on their list. But who knows? With enough marketing, pseudo-science, and fiction... We get enough garbage pushed on us from salesmen.

Calm down, gentlemen.
It would be really convenient to get definitive led specs from philips before anyone throws the next stone. Three definitive advantages I can see so far, is less power consumption, less heat and longer longevity (leds), don´t know about lumens though.

There would probably be more heat, and more power consumption with LEDs. and LEDs are less effecient in terms of output light, however their light can be harness more effeciently.

You said the KEY word .... DESIRED OUTPUT. an MH BULB is NOT a controlled source of LIGHT. in most cases we want light to go in a certain direction. Street lamps we want the light to shine down, in our projectors we want the light to shine in the direction of the LCD ect.

WITH an LED you can achieve your DESIRED OUTPUT in alot of situations with less lumens than with an MH bulb.

For example ..... ill futher clarify one of the possible street lamp scenarios.

I dont know the exact lumens a street lamp has, so I will just throw a number out there ..... 500Lumens .....

Now, the engineer wants 500 lumens of light shining down on the street, he will have to use a bulb that produces MORE than 500 lumens, because alot of light will be wasted. Using a reflector helps, but just like when you look into the fan hole of your DIY PJ, you see alot of light going where WE dont want it too ..... so lets say he needs to use a bulb that puts out 700 lumens in order to do his job ... (Again im just using numbers to illustrate)

That same engineer decides he wants to incquire about an LED setup. He determines that sinces the LEDs are far more directional with their light output in a controlled setting, he can harness more of their output light. and Determines that he only needs an LED setput of 550 Lumens to do the same job.

In the end the same amount of light reaches the concrete on the street. Yes, more light is created by the MH bulb, but unfortunatly more light is lost by the MH bulb. Which at the end of the day, an LED is more EFFECIENT in some applications




Yes, the bulb doenst create any more light, but it can be intensified for its use, and it can force more light into the directions we want it. Of course plenty of light would still be lost. Thats why adding a reflector to our DIY PJs are a good idea .... we got more light on the screen with the same power consumption ..... Adding a reflector doesnt increase power consumption ....



If you sit in the middle of a room and huddle around an MH bulb like its a campfire ... then YES the MH BULB is more effecient ..... But other than that I cannot think of an application that MH bulbs are used, in which light is desired 360 degrees around the bulb .....Even in warehouse lightings (their most common aspect), they arent used for 360 degrees around the bulb ... but rather the bulbs are shined stright down, intending to light of the shophouse floor ....In any situation where you want light to go in a certain direction, if you use a light source that is more controlled like an LED, you can get the same job DONE, with a lower lumen output source ....

Effecieny doesnt stop at their power consumption only .... or else the issue with the street lamps, and with everything would be based around simple power consumption effecieny and not paying attention to other relevant effeciencies ....

as an electrical engineer, I often have to correct power factors, to make things more effecient in power consumption, but that doesnt mean that end of the line stops there. Thats why engineers across the world are switching to LEDs in alot of lightings situations. Granted the lumen/watt ratio from the source itself is worse, but sometimes it goes alot further than how many lumens the source creates. lenses, color filters, wasted light, replacement frequency, all of that matters, and all of that determines the overall effeciency of a product. After all how could the thousands of engineers across the world be wrong in switching to LEDs in traffic lights, railway crossings, street lamps ect ...... IT HAS TO BE MORE EFFECIENT ... CAUSE THEY ALL WANT TO SAVE MONEY .....

It is very obvious to see why they work out far cheaper for things like signal lighting, or anything where you want a specific colour, because LEDs are available in very short spectrums, so they only produce the light thats needed, thus eliminating the need for filters, thus drastically improving efficiency.

However, what i don't know is the efficiency of using reflectors in the warehouse type HID lights. Scubasteve, whats to stop people using reflectors to direct all 360 degrees of light in a downwards direction?

ahhh ... You cant ..... thats whats stopping them ...... You can block light, but you cant take it and send it in another direction .... you can some of the light, but not all of it

Thats why our reflectors dont block light from escaping the back of your PJ (when you build one) ..... Granted using a reflector will reflect some of the light back onto the floor, but it cant reflect ALL of the light ..... with a lamp/bulb there will always be more wasted light ....

with an LED there will be wasted light too, but in their physical characteristic they are far more directional ... thats why they are often rated with a viewing angle. This allows more of their light to be harnessed in a certain direction....

What it all boils down to, is if the harnessing of their light can overcome there lumen/wattage ratio. ....

You also have to consider heat. While an LED system with the same wattage consumption will generate more heat, what about a system in which your using alot lower wattage LED system.

For example .....

Our PJs ... like in the other thread, 80% of an MH bulb is wasted for our use ..... we have to deal with heat of that wasted 80% ..... while using an LED setup (ignoring the axis relativity), we wouldnt generate as much heat, because we would only be using about 10,000-12,000 lumens ..... Even though the lumen to lumen rating of an LED produces more heat, and waste more electricity ..... the harnessing of the light is sometimes good enough to OVERCOME that ... in some cases it will, and in some cases it wont ..... It depends on the situation ....

and it definatly depends on the ability to be able to see past the one element of lumen/watt ratio ....thousands of other factors come into the picture when determining a devices overall effeciency ....

WOW!! Who would'a thought a simple news headline would get everyone so riled up.

So many experts. So little experience.

ok scuba, i like your argues .

anyway i don´t know if it is effeciency the word you should use... Actually my english is soo limited that I have serious problems to argue with you .

In spanish; "rendimiento y eficiencia " are two different things, one does mean lumens/watt but the other is something like what you are saiyng invloving all things (color filter... reflector...) so final output is less.

Anyway, I hold by now we should keep on the MH, but I don´t discart to the leds as a future posibility, somehow far yet...

we leave it in a draw?

fair enough ...

Im in electrical engineer, so when I say effeciency Im usually refeering to electrical power versus output ... but in terms of the ENGLISH language. Effeciency is a common term relative between work performed (output) versus Input ....

We use the term effeciency in everything .....

Ahem.. I think you mean American "ENGLISH".

Nope ... Just ENGLISH in general ....

Im sure over across the sea you guys use the word effeciency as a broad term as well, not just relative to power consumption ....

We do indeed, but for all you know we may not have done, or it could have been one of those different-spelling situations like "color vs colour"

EDIT: correcting typo.

I'm surprised that no-one in this thread sofar has mentioned the true measure of (usable) light, the Lux.



The efficiency of any luminaire must therefore be Lux/Watt (output over input). and should be pretty easy to measure. It'd just take someone to take the two measurements and do the math - no speculation whatsoever.

or i could be totally wrong

lux/wat, mmm do you mean the lux on the lcd?

this is very relative value, since we have different size lcd and diferent condenser lense will have diferent lux values with same lamp...

I believe it is something like candelas directed to the lcd what you mean. The candelas units will tell you how much light is hiting the lcd.

candela is the lumens on 1 stereoradian solid angle.

You are correct ....... This is exactly what I said many many times above ..... I debated the overall effeciency of the lighting rig (how much light actually shines where you want it to) versus how bright the source was .....