LED lumens vs metal halide lumens?

idleprocess

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30x80m are 2400m². So 36000lm can create a illuminance of 15lx (with optimum beam angle).
An subway track in london has 150lx.
en.wikipedia.org/wiki/Lux#Illuminance

To reach 150lx you would need at least 360000lm (would draw 3000W / 3kW).

Given that all other measurements the post you cited expressed explicitly are in feet, I believe you're off roughly an order of magnitude high using square meters. It's more like 223 square meters.

EDIT: We're also four years on since the OP last participated in this thread.
 
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degarb

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Not many are over 120K lumens, at that is at the bulb level before losses. MH fixtures are generally less efficient than LED fixtures.

Electronic ballasts are more efficient than magnetic. http://vi.raptor.ebaydesc.com/ws/eB...tegory=178989&pm=1&ds=0&t=1511511602000&ver=0 Can easily put out 120k lumen, lamp level (claiming 140k lumen, probably 110K protected) 14k lux at 5'8" (do math for candela, nearly 13k x4, typically 4k lux for a good sized wall in the field. ) . Using only 1000 watts. For work application, $200, works great. Before, I used a wall of lights, with lesser results.... For led, you have ac dc loss, huge heat sink loss, price barriers to be broken. The other factor to keep in mind is that inside v. Outside, are completely different animals to light up. Photons inside do not commonly get instantly absorbed, rather bounce around, raising lux to surprising levels, beyond predictable candela rating. Outside, yes, usually, only lux matters. For example, at Sherwin Williams, where we do color matches, it is clear the led tube retrofit is a downgrade that is hard to finger. The engineers only took lux and cri into consideration, forgetting the rest of the photon story after the first bounce-lower lumens, lower worker and shopper light induced alertness, due to lower store lumen level.

Show me a $200ish led light with over 100K lumens, a good form factor, and I will buy. Though I paid only $140 for my second 1000W 120k lumen MH on ebay.
After owning this light and struggling with sub 80k lumen setups, I now know how much light we need. Though, will always be flexible for a small, convenient form factor, or cheap price tag (my 500 watt smd based led light, claiming 50k lumens-30k in reality, is worth $50,but I overpaid $100 on ebay, because of led buyer excitement. My generic 50 watt cob burned out after 2 dozen hours, had to solder in a 100w cob, so far underdriven has worked well-so I don't trust ratings on generic led cob emitters, but dang, so cheap, it is nearly impossible to avoid. )... The 250 watt led 70 deg ,claiming 30k lumen spot for $160 is exciting, until I remember testing my 24K lumen Tota against my 1000W Mh, and seeing no contest. Also, 4x, per data sheet, at $160 a pop, with roughly same efficiency as mh. Nonetheless, exciting to see gaining ground. Just reminding, that, ain't there :yet. But wait 2-4 years, at $50 for 30k lumens, will be there to match my 1000W mh. Though, right now, the target is the lower hanging fruit, the lower low and output of the common 400 w mh, which is a light I own several, but never excited me. And I hate my 150 w MH, but tolerate it to light my garage,feeling it unfit for job use... Also, I would not take lightly that the led light is more suited than my indoor electronic ballasted mh outside in rain,buggy environment, and where only candela and beam pattern matter. Though I do respect quality mh reflector v. A poorly designed one, like on my junkie $20 second hand 150w Lithuania mh,which retailed for a ripoff price.
 
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chiller791

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The problem with high wattage MH is they create a lot of light and a lot of heat radiating from a small area, typically one square foot with fixture. While you can light a large area with that 1000watt halide for cheap the quality and distribution of light is *terrible*. This is why the only environments still using this type of lighting are parking lots, etc., basically where you want a lot of light for cheap and often to scare off thieves and give the impression of security.

I'll illustrate this: if you have a 50x50' work area, and you were somebody working in that environment, would you rather have a single 1000watt blazing metal halide from a single point in the room, or lots of LED fixtures distributed around creating even light distribution? I dare say most people including OHSA would prefer the later. When you roll fixture efficiency into the equation, along with distributing light evenly to all work areas suddenly your lumen requirement drops to half if not more compared to that 400/1000watt discharge.

Also, the industry is moving away from dense, high powered LED sources and more towards distributed, low powered LED; strips etc. The biggest reason is the later don't require heat sinks. Not sure what Degarb is working with (Ebay Chinese arrays I guess given 90% of what's being discussed in this thread *is* Ebay tech) but the Philips and Cree solutions I works with crush discharge in every dept. and I have no problems filling 10k ^ 2 feet with LED at high CRI levels. I can create a LED installation so that a customer can dial in their preferred color temp using simple dimmer controls (try that with MH), or schedule light levels and color temps, or put LEDs on a motion control and after down conversion I'm not dealing with lethal voltages and UV shields. Again, try that with MH.

If you prefer pinpoint light sources to create obnoxious shadows and reduce worker productivity stick to MH.
 

idleprocess

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Not sure what Degarb is working with (Ebay Chinese arrays I guess given 90% of what's being discussed in this thread *is* Ebay tech) but the Philips and Cree solutions I works with crush discharge in every dept. and I have no problems filling 10k ^ 2 feet with LED at high CRI levels. I can create a LED installation so that a customer can dial in their preferred color temp using simple dimmer controls (try that with MH), or schedule light levels and color temps, or put LEDs on a motion control and after down conversion I'm not dealing with lethal voltages and UV shields. Again, try that with MH.

If you prefer pinpoint light sources to create obnoxious shadows and reduce worker productivity stick to MH.

I believe that Degarb is doing construction jobsites where the lighting is by necessity both temporary and portable. As such, a couple of intense point sources supported by headlamps or task lights for workers may be all that's practical.
 

degarb

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You are correct Idle.

I am not a city. Personal pocket.

The lumen per dollar, when you really want 200,000 lumens per one 115volt circuit, didn't make sense with Cree last cob pricing.
Plus, I am using winged mh reflectors that has a very satisfying light reflection and distribution, unlike the Lithuania parking light I bought.

Wake me when you can get 120k (ansi lumens , not exaggerated lies, typical of China lights) lumens (under 1000 plug watts) for $150, including heatsink and power supply. Cri is over rated for eyeballs, not photography. I did extensive spectrometer tests last year. Made 2 pizza boxes with 150 over lapping color swatches of very slightly differing hues, in every color family. Cri had squat to do with color discrimination between hues for the eyeball. Luminance mattered. Sure cri mattered to the camera. For the eye, just a preference, largely. If anything, color is cri+gai+luminance-like the research of the last 3 decades showed. Cri is madness, an obsession by pale people to look healthier. In some cases high yields worse colors. Hopefully, the newer engineer standard TM 30 - 15, will end the cri madness. TM-30-15 is hardly memorable, and desperately needs better name, like XCRI, to catch on... Still, luminance is Huge to color perception for the eye. Huge!

As a disclaimer, before someone jumps in, yes there are low cri light sources that may be so monochrome, shifted, whatever, that they are of little use. We can argue all year where the cut off, and why some lower cri look better than what ever. .. Cri is just a part of the equation. Unfortunately, an obsession
 
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georges_devontae

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It depends on your assumptions. An LED drops to 70% output in a few years. T5 florescent drops to 90% in about a year. Metal halide is somewhere in between.

Does the LED distribute light better or worse? Does the relamp savings matter? Lumens are lumens, but LED gives you more options (CRI, CCT, beam pattern) at a higher cost. Right now it looks like, unless someone gives you a hefty discount on the fixtures, LEDs aren't it for high bay lighting. Maybe in three years, outside special cases.

It's just power intensive to light a work floor. Some shop owners can skimp general lighting to focus on task lighting. What measurement says you need another 4-6 units? Where do you need what levels of brightness?

but nowadays majority of led lighting has life span of 50000hours at L70, which may exceed a few years.
 

ssanasisredna

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but nowadays majority of led lighting has life span of 50000hours at L70, which may exceed a few years.

That was true when that original comment was made almost 5 years ago. That 5 year old comment was not terribly accurate then, and definitely is not now.
 

idleprocess

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That was true when that original comment was made almost 5 years ago. That 5 year old comment was not terribly accurate then, and definitely is not now.

LED fixtures do seem to be suffering a similar fate to CFL: price-cutting at the expense of quality.
 
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