Barbarin
Flashlight Enthusiast
Hi guys,
I'm in Paris, in Eurosatory show... This is what I have seen there.
I'm in Paris, in Eurosatory show... This is what I have seen there.
Hummer goes for LED headlights!!!
- Thread starter Barbarin
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PhotonBoy
Flashlight Enthusiast
The LEDs won't affect the Hummer's fuel economy very much. :shakehead
There is SO MUCH metal around them to use as heatsink that i doubt that will be much of a problem.
Also, i think one advantage for the military is the redundancy: Even if 1...2...3 of the LEDs break, the driver can still see where he is going.
In situation where a light might be break because of a bullet or something...
Illum
Flashaholic
you oughta see the radiators on mil-spec humvees, they can idle the ting in the desert without overheating, I'm pretty sure the LEDs can only generate a fraction of the heat the power plant makes
Beastmaster
Enlightened
Hey, great link. I was able to work around the linked site's faulty coding and find
this large image.
It bears lens markings indicating compliance with US Federal Motor Vehicle Safety Standard 108. It also bears aiming pads for use with mechanical aimers, which is — again — a measure nominally intended for compliance with FMVSS 108's requirements that headlamps physically capable of fitting into a mount with horizontal aimability be equipped with a horizontal VHAD, since visual/optical horizontal aimability is not permitted by FMVSS 108.
This just got a whole lot more "real" and interesting. The linked Kascar site wants $441 each, which is notable given that Valeo-Sylvania gets $500 apiece for their projector BiXenon 7" round retrofit.
this large image.
It bears lens markings indicating compliance with US Federal Motor Vehicle Safety Standard 108. It also bears aiming pads for use with mechanical aimers, which is — again — a measure nominally intended for compliance with FMVSS 108's requirements that headlamps physically capable of fitting into a mount with horizontal aimability be equipped with a horizontal VHAD, since visual/optical horizontal aimability is not permitted by FMVSS 108.
This just got a whole lot more "real" and interesting. The linked Kascar site wants $441 each, which is notable given that Valeo-Sylvania gets $500 apiece for their projector BiXenon 7" round retrofit.
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VanIsleDSM
Enlightened
Very interesting.. need lumen specs and beemshots.
TorchBoy
Flashlight Enthusiast
Weirdness. Don't forget to not hotlink, tho.
Hotlink removed. I agree, beam shots and photometry needed. One thing that kind of jags on me about this lamp is that it appears to have a plastic (i.e., polycarbonate) lens. Those haven't ever held up well in automotive headlamp lens service, so we may be looking at "forever" light sources with an age-prone, non-replaceable lens. That'd be AFU.
Illum
Flashaholic
no worried bud, I had it rehosted via. imageshack.us
beamshot maybe, but I'm not to thrilled as to what the photometry would look as your considering multiple emitters
at that price it better have a dedicated driver and heatsink:green:
Not just a bridge rectifier and resistors
beamshot maybe, but I'm not to thrilled as to what the photometry would look as your considering multiple emitters
at that price it better have a dedicated driver and heatsink:green:
Not just a bridge rectifier and resistors
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Beastmaster
Enlightened
Arrrrgh...useless pics of the illuminated headlamp, but no beam shots!
This is specifically mentioned as a significant production challenge in the SAE paper on the Lexus LS600h LED headlamp (SAE #2008-01-0339); multiple emitters w/multiple optics to create the different parts of the beam all work well when everything's aligned as it's meant to be, but if the various components are out of alignment, the beam formation goes crapwise.
The two issues with headlamps installed in a military vehicle and specifically one used in Iraq are heat and dust.
The front cover is made of clear Polycarbonate - no matter the quantity of UV additive in the original resin, in desert conditions it will quickly become yellow and brittle.
But before this will happen, probably the scratches will reduce the output considerably.
Sand, wind, and total dry environment act like a sanpaper on the hard Polycarbonate headlight's lens which will become a primary source of disturbance to other drivers.
Regarding heat, in this extermely hot environment any heat sink will become a heat accumulator. I think is a mistake to look at the vehicle's mass of metal as a large heatsink.
Just as a reminder, try touching the car's windshield on top in a hot summer day when entering the car after a couple of hours. It goes to almost 80 deg C.
In the desert the temperature is even higher.
The LED's starting point is at a very high temperature. New and high quality Hi Power types will work, but with considerably reduced working hours.
The primary objective of using LED rather than conventional lamps is mechanical resistance mainly.
What worries me is something else:
It is known that at a given constant current the LED's output is influenced by the environment's heat. The output decreases when hot and increases when cold. That means that if the same hummer will be relocated in Alaska, the headlights will be almost 160% brighter !!! but what about Iraqi desert?
I see that the headlight has the DOT mark on it I wonder how it passed the SAE tests.
Anyone has an idea if they are used in real life or only assembled on a concept vehicle for show?
The front cover is made of clear Polycarbonate - no matter the quantity of UV additive in the original resin, in desert conditions it will quickly become yellow and brittle.
But before this will happen, probably the scratches will reduce the output considerably.
Sand, wind, and total dry environment act like a sanpaper on the hard Polycarbonate headlight's lens which will become a primary source of disturbance to other drivers.
Regarding heat, in this extermely hot environment any heat sink will become a heat accumulator. I think is a mistake to look at the vehicle's mass of metal as a large heatsink.
Just as a reminder, try touching the car's windshield on top in a hot summer day when entering the car after a couple of hours. It goes to almost 80 deg C.
In the desert the temperature is even higher.
The LED's starting point is at a very high temperature. New and high quality Hi Power types will work, but with considerably reduced working hours.
The primary objective of using LED rather than conventional lamps is mechanical resistance mainly.
What worries me is something else:
It is known that at a given constant current the LED's output is influenced by the environment's heat. The output decreases when hot and increases when cold. That means that if the same hummer will be relocated in Alaska, the headlights will be almost 160% brighter !!! but what about Iraqi desert?
I see that the headlight has the DOT mark on it I wonder how it passed the SAE tests.
Anyone has an idea if they are used in real life or only assembled on a concept vehicle for show?
Agreed. It seems to me toughened borosilicate (hard) glass might've been a better choice. But I didn't spec this part, a military contractor did, so there must've been a reason for using polycarbonate. That said, while I'm not sure glare-to-other-drivers is very high up on the list of concerns in Iraq right now, unintended diffusion by lens abrasion and opacification will significantly reduce the seeing-light performance and increase the glare and backscatter.
That is a good and interesting point. A heat sink doesn't know or care which way the thermal gradient goes; it's just a conductor of heat. If the thermal gradient is such that the component mounted to it is hotter than ambient, you have a heat sink. If ambient is hotter than the component, then you have a heat...accumulator-focuser-thing. What's the opposite of a sink, a faucet? ;-)
Agreed. It doesn't work this way.
This is why LED vehicle lamps have sophisticated control circuitry that alters the drive power profile to maintain constant output (or at least maintain output within acceptable parameters). I cannot imagine this lamp being an exception to that. Will it work well in the real world? Don't know, wait and see.
They're (unofficially) going on the 2009 Hummers, and there are unspecified additional versions soon to be released.
I see some 10 LEDs in this headlight. This setup needs separate LEDs for the high beam and low beam. Assuming the minimum 800 lumen needed to produce a relatively medium intensity headlight (although 1000-1100 lumen is the common 55W halogen) means the headlight uses 200 lm LEDs at least, meaning very new 5W emitters.
I looked at the behind of this lamp - posted by Beastmaster - it is not as large as I thought, in fact is quite small. Even if the electrical system won't allow hi/low to be activated together there are still 25W (or more) to be dissipated.
From the photo it is not clear if the heat sink fins are horizontal (which is a wrong design) or vertical.
Based on my experience with such vehicles and desert conditions dust will accumulate quickly between the fins. Desert dust is like powder and combined with little humidity it clogs and is very hard to remove even by air ventilation.
Regarding the lens, military guys are inlove with polycardonate, this is right - the lamp was probably designed to some spec provided. But a 5 in. diameter or more I guess is vulnerable to impact from stones and not to mention combat situations with mines and grenades exploding nearby.
I see 3 wires entering the lamp, probably common gnd, hi and low beam. In the company's website there is a separate controller needed - from all that is not clear if the lamp is so sophisticated from the controller aspect, this is when speaking about intensity vs. temperature compensation control.
One year ago I designed a headlight for a tank, so far with some 50 installed and tested.
This is to explain my interest in this subject.
I placed a photo of it in this thread: http://www.candlepowerforums.com/vb/showthread.php?t=198606
What I say in such situation, based on my 10 years of experience with LED technology is "let's wait an see" - the problem with leds is they don't burn immediately; it takes a while and a wrong design will show damaged or degradated output after 1000 hours at least.
I looked at the behind of this lamp - posted by Beastmaster - it is not as large as I thought, in fact is quite small. Even if the electrical system won't allow hi/low to be activated together there are still 25W (or more) to be dissipated.
From the photo it is not clear if the heat sink fins are horizontal (which is a wrong design) or vertical.
Based on my experience with such vehicles and desert conditions dust will accumulate quickly between the fins. Desert dust is like powder and combined with little humidity it clogs and is very hard to remove even by air ventilation.
Regarding the lens, military guys are inlove with polycardonate, this is right - the lamp was probably designed to some spec provided. But a 5 in. diameter or more I guess is vulnerable to impact from stones and not to mention combat situations with mines and grenades exploding nearby.
I see 3 wires entering the lamp, probably common gnd, hi and low beam. In the company's website there is a separate controller needed - from all that is not clear if the lamp is so sophisticated from the controller aspect, this is when speaking about intensity vs. temperature compensation control.
One year ago I designed a headlight for a tank, so far with some 50 installed and tested.
This is to explain my interest in this subject.
I placed a photo of it in this thread: http://www.candlepowerforums.com/vb/showthread.php?t=198606
What I say in such situation, based on my 10 years of experience with LED technology is "let's wait an see" - the problem with leds is they don't burn immediately; it takes a while and a wrong design will show damaged or degradated output after 1000 hours at least.
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Actually more like 1000-1500 lumen if we look at H1, H3, H7, H11, rather than just the relatively dim US-favored 9006...then there's the HIR2/9011, 1875 lumen @ 55w...
Vertical. I compared the locating lugs' placement in the photo with the placement specs for the 7" round size format, and it's clear that the dark gray round Gore-Tex hydrophobic breather we see in the photo is "up" when the headlamp is installed, but in this photo it's pointing to the right. So they did orient the fins correctly.
Another good point. Seal the buckets and you cut off air circulation. Open the buckets to airflow and you get dust ingress. Of course, this being a mil-spec project, the buckets could be sealed to ambient but ducted to cabin A/C or something...
More. 7".
...??? I didn't see any separate controller called for. Got a link, please?
I agree!
