A few questions about HID lights.

[mickb]

guys I probably used HID in the day before knowing or caring what they were, or anything about lumens. And its still a grey area having gotten into high power LED lights the last few years.

Wondered if anyone can someone explain the theory quickly, relevant timeline of development, and how they compare to handheld LED spotlights? Any short matrix style crash course paragraph on the subject would be highly appreciated.

 

[Polarion-Sparetech2]

Start here: https://en.wikipedia.org/wiki/High-intensity_discharge_lamp

LED = flat emitters, can be hard to focus, monochromatic, heat management critical in high power applications. Many claims are based on over-driven modes that work for a few seconds.
HID = more or less point source, easier to form into a beam, wide-spectrum emitter, from UV to deep IR, heat management less complicated, can be left on for hours at a time.

No right or wrong answer, just 2 different technologies with pros and cons. Everything depends on customer requirements.

 

[Dr. Mario]

Not to mention that some metal halide bulbs have better color quality (especially with 4,200 Kelvin version being quoted to be at between CRI of 92 to 98, with Sun being practically CRI of 100), especially with the ceramic metal halide bulbs which are comparatively recent invention compared to the classic Quartz arc tube metal halide bulbs we're familiar with.

Most LEDs, except for the brand name LEDs, especially those from Nichia, have poor color quality, which can be anywhere from bluish to greenish tints, so there's some applications where LEDs can't touch HID lamps (hence why I still own a modified Cyclops Thor Colossus Halogen spotlight fit with ceramic metal halide HID lamp, it just work for some use where color representation is important - and I also have Nichia x19 LED flashlights so I knew how good those LEDs are - very close to the ceramic metal halide bulb in term of CRI quality as far as I can see).

Lastly, the metal halide bulbs use certain mixture of metal salts, such as Tin Iodide, Thallium Iodide / Bromide and Sodium Iodide, to name a few to effectively modify the color temperature of the arc, so you have several options of what you want or need for to use. Monochromatic metal halide bulbs also exists, like Thallium Iodide green metal halide bulb for instance. Metal atoms themselves emit light rather than the electrical arc in the arc tube.

 

[yellow]

Not to forget:
Led - more (or less) totally unaffected from bumps/vibrations,
while HID are not this rugged.

 

[idleprocess]

As I understand it...

HID

• operation : Arc lamp ignited by multi-KV DC pulse that transitions to an ~85V AC operating state shortly post-ignition. As an arc lamp its emission characteristics are profoundly spiky; this can be mitigated through adjustments to the fill gas and compounds within the capsule that vaporize upon arc ignition (thus HID lamps' color shift post startup).
• pros : Easily collimated into a tight beam, largely operating temperature indifferent, greater effective light (intensity/lumen) density per source than LED
• cons : High-temperature / high-pressure / high-voltage lamp operation, outer bulb envelope does not trap all emitted UV, bulb / igniter / ballast can all wear out, generally less efficient than LED, generally physically larger and heavier than LED, inherently more complex

LED

• operation : DC voltage to a light-emitting diode causes blue light to be emitted which is shifted to a wide spectrum using a phosphor coating. Varying the phosphor coating and specific wavelength of the blue LED alters the emission spectrum, however all LED will feature a strong blue peak.
• pros : Low-voltage / low-temperature operation, simple DC operation, no UV emissions, high CRI is available, can be packaged very small relative to HID, generally more efficient than HID, lower complexity
• cons : Large emitting area makes tight collimation more difficult than HID, thermals must be given great care in design, in operation overheating is a real concern, failed components aren't usually field-serviceable

In general when it comes to the heavyweight spotlight, HID is king of the hill. The downside is pretty much everything else - they're big, heavy, expensive, produce considerable heat, consume considerable power.

Conversely while you can source a variety of LED throwers that can be so compact as to be pocketable, they're going to come up short vs HID. To the extent I've seen LED attempt to compete in the heavyweight spotlight category they're enormous, feature active cooling for the LED (and possibly the driver), and ultimately approach the power consumption of HID.

Thus, LED's with long reach are generally described as throwers rather than spotlights.

 

[XeRay]

HID is pretty darned robust, can be be commonly mounted on 50 cal machine guns (recoil) also in our case M1 Abrams Tanks next to the main artillery barrel. If you drop HID from a "good" height onto a very firm surface such as concrete, the lateral G forces are high enough to pull the plasma (has mass) out of the electrode arc gap and it will go out, but can be re-lit instantly. D1S and D2S offer 90-115 (35-80 Watts) lumens per watt depending on how many watts they are fed. The higher power HID offers more lumens per watt. High Power CREE LED's we use are about 120 Lumens per watt at about 13 watts each, so in reality not so much difference there. To do this effectively, very efficient thermal management is requires with active cooling. Both of theses together make possible sustained output of the LED's with extended full output continuous operation.

 

[alpg88]

those "robust HIDs" are much much more expensive, and more complex than a LED that is just as robust, they are not always available to general public either, but when it comes to helicopter/ship searchlights, nothing beats hid, for now.

 

[theory816]

In terms of hand held, I just don't see how an HID flashlight can beat out an LED one because of pure form factor. Deciding wether to use HIDs and LEDs depends on the demands. For example, I wouldn't use LED's on car headlights. I also wouldn't use LEDs on street lights.

 

[idleprocess]

In terms of hand held, I just don't see how an HID flashlight can beat out an LED one because of pure form factor. Deciding wether to use HIDs and LEDs depends on the demands.

HID is easier to collimate than LED because its source surface area is smaller and emits more flux per unit area than LED. Thus when one has volume/mass/power/thermal margin to spare, HID will easily offer superior throw while being markedly more heat-tolerant than LED and serviceable (bulbs, are field-replaceable as are ignitors, ballasts in many applications). In addition to the formfactor penalties, the cost is also greater as well due to the relatively high-energy physics: high voltages, high temperatures, high pressures (within the HID capsule), stray UV. Ergo my characterization of HID as the heavyweight spotlight king - fitting since ~10W is the smallest HID capsule I've encountered.

For example, I wouldn't use LED's on car headlights. I also wouldn't use LEDs on street lights.

The markets are going the other way and have been for some time. Presumably the performance of LED is proving adequate while costing manufacturers less than HID (or the various arc lamp topologies in the case of street lights) or offering operational advantages, although the novelty of the designs are playing a role in the automotive space.

 

[theory816]

HID is easier to collimate than LED because its source surface area is smaller and emits more flux per unit area than LED. Thus when one has volume/mass/power/thermal margin to spare, HID will easily offer superior throw while being markedly more heat-tolerant than LED and serviceable (bulbs, are field-replaceable as are ignitors, ballasts in many applications). In addition to the formfactor penalties, the cost is also greater as well due to the relatively high-energy physics: high voltages, high temperatures, high pressures (within the HID capsule), stray UV. Ergo my characterization of HID as the heavyweight spotlight king - fitting since ~10W is the smallest HID capsule I've encountered.


The markets are going the other way and have been for some time. Presumably the performance of LED is proving adequate while costing manufacturers less than HID (or the various arc lamp topologies in the case of street lights) or offering operational advantages, although the novelty of the designs are playing a role in the automotive space.

To be honest I don't know much about HIDs and LEDs in the flashlight context. Is there a source on this forums that can get me up to speed with the HIDs? If you talk to a layperson though, the momentum is in favor of LEDs for everything. Try and persuade them that HIDs is still a great technology and should still be used and they'll go haywire for some reason.

 

[idleprocess]

To be honest I don't know much about HIDs and LEDs in the flashlight context. Is there a source on this forums that can get me up to speed with the HIDs?

I took a stab at it in post 5, otherwise I'm not aware of any such resource. Daniel Stern has some writings on the subject, however the articles are light on technical detail and strong on missive as to how the automotive "HID kit" is a Bad Idea™ (which it is).

If you talk to a layperson though, the momentum is in favor of LEDs for everything.

This has been the broader flashlight market reality from my perspective once the power LED established itself some ~20 years ago. After the market moved on from the expensive and difficult-to-work with (from an electronics-manufacturing perspective) original Lumileds Luxeon, LED quickly ate into the market share of all others for more general-purpose flashlights.

Spotlights are a specialized beast, however. ~20 years ago the choice was halogen at the low end and and HID at the high end. This has seemingly morphed into a LED and HID. LED spotlights seem to have largely evolved into long-throw variants of conventional flashlights and are typically described as throwers. HID spotlights tend to retain the large boxy formfactor reminiscent of 6V lantern flashlights out of necessity due to their significant power requirements and the demands for a large-diameter reflector in order to achieve good throw.

Try and persuade them that HIDs is still a great technology and should still be used and they'll go haywire for some reason.

For the average person - even on CPF - LED is the obvious choice due to availability and ease of use. It's only once you have the need for greater performance and budget (money, power, weight, volume) that you're likely to choose HID.

 

[theory816]

I took a stab at it in post 5, otherwise I'm not aware of any such resource. Daniel Stern has some writings on the subject, however the articles are light on technical detail and strong on missive as to how the automotive "HID kit" is a Bad Idea™ (which it is).


This has been the broader flashlight market reality from my perspective once the power LED established itself some ~20 years ago. After the market moved on from the expensive and difficult-to-work with (from an electronics-manufacturing perspective) original Lumileds Luxeon, LED quickly ate into the market share of all others for more general-purpose flashlights.

Spotlights are a specialized beast, however. ~20 years ago the choice was halogen at the low end and and HID at the high end. This has seemingly morphed into a LED and HID. LED spotlights seem to have largely evolved into long-throw variants of conventional flashlights and are typically described as throwers. HID spotlights tend to retain the large boxy formfactor reminiscent of 6V lantern flashlights out of necessity due to their significant power requirements and the demands for a large-diameter reflector in order to achieve good throw.


For the average person - even on CPF - LED is the obvious choice due to availability and ease of use. It's only once you have the need for greater performance and budget (money, power, weight, volume) that you're likely to choose HID.

I'll have to read up on it. But in what cases would the HIDs be used for?

 

[idleprocess]

I'll have to read up on it. But in what cases would the HIDs be used for?

HID normally refers to automotive D-series bulbs, powered at 35 or 25%. Use cases are essentially spotlights and automotive headlamps. D2S is one of the more popular for spotlight applications (albeit not always featuring a D2 socket) since it features a separate ignitor and has been around for so long.

 

[XeRay]

I wouldn't call this boxy, 50/70 watt HID battery powered searchlight. Most good HID searchlights in recent (10-15) years have been of this configuration. This uses D1S or a D1 shaped Igniter with a D2 based (P32d) bulb. Search and rescue, or military/police application primarily.

 

[theory816]

Nice. Looks like I still have a strong case for HID street lights over LEDs that are turning purple after a summer

What a great invention hids.

 

[Mosports]

Nice. Looks like I still have a strong case for HID street lights over LEDs that are turning purple after a summer

What a great invention hids.

I am a Hella Distributer. Three years ago we received a letter from Hella saying that HID had progressed as far as it was going to and that they were not going to do any more Research and Development on HID.

 

[theory816]

I am a Hella Distributer. Three years ago we received a letter from Hella saying that HID had progressed as far as it was going to and that they were not going to do any more Research and Development on HID.

All the more reasons to go with HIDs!