Are LEDs more Robust and Efficient than HIDs?

[xiaowenzu]

I know that HIDs brag that they don't have a filament to burn, but LEDs don't have a filament either, just electric current which produce light surround by tough epoxy. HIDs are filled with gas which when heated emit light.

Also are LEDs more efficient than HIDs.. I sometimes read that HIDs are the most efficient lighting system, even more so than LEDs.

Lets hope someday that HID flashlights can be shrinked into a small hand-held factor (something the size of a Surefire E2e and requires small start-up voltage.

OR, lets hope soon we can reach the LED theoretical limit of 400 Lumens/watt. That would be right in the HID territory! Either way, it's going to be a bright future! Pun intended. heheh

 

[NAW]

I believe HIDs can reach more lumens/watt than LEDs. One of the main advantages HID has over LED is the capability of reach higher lumens (8500 lumens is what the brightest HID called the "BarnBurner" is capable of) & they are fully regulated.

LEDs have the advantage of being able to have selectable brightness outputs.

HID manufacturers are getting HIDs to be more smaller. I doubt they will be as small as a E2E but the technology is still improving.

 

[xiaowenzu]

Thanks for the info! Yep, current HIDs reach about 114 Lumens/watt such as the Polarian Helio 35watt which produce 4000 Lumens. However LEDs are becoming more efficient too. The Latest Osram Ostar can reach 75lu/watt, producing 1000 Lumens total!

http://www.osram-os.com/news/news-OSTAR-1000lumen.php?lan=eng&id=159

Now only if they can reduce it to a 1x1mm die and run it off 3v instead of 20v.

I agree that both HID & LED technologies are improving rapidly. Leds are becoming more efficient, thus achieving ever higher lumens, whilst HIDs are becoming smaller. Lets hope we'll soon have a 'barnburner' in our little hands!

Although I have to admit I prefer LED technology, simply because as you said, can vary the brightness. That's very important because you don't want 9000 Lumens ALL the time. And because LEDs don't produce much heat and are SILENT to start-up (great for tactical signalling!)

 

[Stella_Polaris]

I KNOW this an LED thread, but to answer your question, check this one out:

http://cgi.ebay.com/35W-28W-DUAL-OUTPUT-RECHARGEABLE-HID-TORCH-FLASHLIGHT_W0QQitemZ180095497682QQcategoryZ106988QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Looks like an awesome light!

 

[TorchBoy]

You know, the only reason "LEDs don't produce much heat" is because they are generally comparatively low power devices. However I can assure you that my Luxeon K2 really does get quite toasty at high currents - certainly hot enough to be very careful of.

IMHO LEDs are more robust than HID but even the best production LEDs are not quite as efficient as HID, and most LEDs really aren't spectacularly efficient even compared to halogen. I believe LED and HID each have their uses, and as yet don't really compete for the same territory. LEDs are very attractive for their relative simplicity, not needing a fancy ballast to be run hard (even a single resistor will do) and like you say, there's a lot more development to be done. Yep, that's pretty exciting.

PS. That HID torch on Ebay is pretty exciting too!

 

[DM51]

HIDs don't like being switched on for brief periods only. If you switch one on, aim to leave it on for a while. There's not much point trying to use HIDs for flashing anyway, as they usually take a few seconds to reach full brightness.

 

[Handlobraesing]

I know that HIDs brag that they don't have a filament to burn, but LEDs don't have a filament either, just electric current which produce light surround by tough epoxy. HIDs are filled with gas which when heated emit light.

LEDs are more durable. An HID lamp can shatter when it strikes something, or when the impact is enough to cause the glass to snap at the base.

Also are LEDs more efficient than HIDs.. I sometimes read that HIDs are the most efficient lighting system, even more so than LEDs.

No one answer. The newer 80+ lm/w LEDs are more efficient than micro HIDs, but you can't beat HIDs when it comes to intensity.

People say LEDs run cool, because they run at very low power in usual applications. They can hold two figure lumens per watt even at fractional watt power, something no HID or incandescent can do.

When it comes to collimated light or amssive amount of light, LEDs lose. Nothing beats LPS, which is around 180 lm/W at 180W.

OR, lets hope soon we can reach the LED theoretical limit of 400 Lumens/watt. That would be right in the HID territory! Either way, it's going to be a bright future! Pun intended. heheh

That will never happen. There is a difference between efficacy and efficiency. Efficiency is Wout/Win. Efficacy is effectiveness/Win.

two 100% efficienct light sources both emitting exactly one watt of light power, but one at deep red and one in green at our eye's maximum sensitivy, the green wins with a big margin, not because of the energy, but because of the way our eyes respond to light.

This web site suggests theoretical maximum for white light is 200 lumen, but green at our maximum sensitivty is said to be around 680 lumen/optical watt

http://www.greenhouse.gov.au/lgmodules/wep/streetlighting/training/training5.html

 

[easilyled]

1) In terms of efficiency ....

I think the answer is "not yet" but certainly potentially given
the quantum leaps in efficiency over the last few years for a
technology that is still in its infancy.

2) In terms of robustness ....

Yes, leds are more robust.

 

[AlecGold]

@ Torch Boy
The K2 is not the best example of a led I guess, the Cree's and Seouls produce much less heat.
but leds are often driven at 60%-80% of their maximum. Driving them lower makes them much, much more efficient. So when a Q4 led is capable of putting out 180lm, it will need over 1,5 watt to be driven that hard. But when driven at 0,7 wat it could perhaps emit 105 or 115 lumens!

 

[TorchBoy]

@ Torch Boy
The K2 is not the best example of a led I guess, the Cree's and Seouls produce much less heat.
but leds are often driven at 60%-80% of their maximum. Driving them lower makes them much, much more efficient. So when a Q4 led is capable of putting out 180lm, it will need over 1,5 watt to be driven that hard. But when driven at 0,7 wat it could perhaps emit 105 or 115 lumens!

I hear what you're saying - I know it's not the most efficient LED around. But I think the K2 is a good example of a really hot-running LED, one that I've had the opportunity to touch when it's running at high current, and that was the point. The high power LEDs that are common these days do get hot.

Unfortunately I haven't had a change to play with a high power Cree or Seoul LED but even with their higher efficiency you're not saying they're not hot are you? At 70 lumens/watt that's still only about 10% efficient. Guess where the other 90% goes to? Yeah, heat.

And even 1 watt of heat gets hot if it doesn't get dissipated quickly enough.

 

[2xTrinity]

I know that HIDs brag that they don't have a filament to burn, but LEDs don't have a filament either, just electric current which produce light surround by tough epoxy. HIDs are filled with gas which when heated emit light.

Well, not exactly. HID are not the same as incandescent (lamps that emit light because they are hot), though they must be warmed up to a certain temperature before they can be efficient. HID lamps produce light due to an electric arc being passed through the gas -- this excites electrons in the gas molecules which then emit light. This is actually more similar to an LED which also emits light due to quantum effects from the current through it, not heat.

The bottom line for a long time to come is that HID is most efficient for high-output lighting, especially for fixed lighting (I don't think we're going to see streetlights and industrial flood lights replaces with LEDs on a wide scale for a VERY long time) For one thing, it's possible to produce over 100,000 lumens from a single HID bulb (a 1000W HID lamp can pull that off no problem) for the price of a relatively few Cree emitters.

Another thing to consider is throw -- higher power LEDs in order to produce more lumens genreally need to have a larger light emitter surface in order to keep from cooking themselves alive (LEDs are very heat sensitive, unlike HID), this limits their ability to be collimated into an extremely tight beam for throw -- which is the niche where HID presently dominates. However, I believe that particular niche will be overtaken in the next several years by all but a few enthusiasts -- but HID will still be king for fixed lighting for decades.

This web site suggests theoretical maximum for white light is 200 lumen, but green at our maximum sensitivty is said to be around 680 lumen/optical watt

http://www.greenhouse.gov.au/lgmodules/wep/streetlighting/training/training5.html

This depends on how you get "White." 200 lm/W is probably the max for broad spectrum white with components in the deep red and deep blue parts of the spectrum. However, an ideal (100% efficient) narrow-spectrum RGB emitter could probably produce almost 400 lumens per watt, and would still appear white.

 

[xiaowenzu]

The bottom line for a long time to come is that HID is most efficient for high-output lighting, especially for fixed lighting (I don't think we're going to see streetlights and industrial flood lights replaces with LEDs on a wide scale for a VERY long time) For one thing, it's possible to produce over 100,000 lumens from a single HID bulb (a 1000W HID lamp can pull that off no problem) for the price of a relatively few Cree emitters.

The HIDs on Luxor hotel at Las Vegas are rated at 7000W EACH! I'm not sure how many Lumen is that, but they have 40 of those lamps.. producing 41.5 gigacandela.
A wild guess would be about 50 Million Lumens. Now if only they can incorporate that whole system into something the size of a U2, I'd be up for it! :laughing:
http://en.wikipedia.org/wiki/Luxor_Hotel

 

[TorchBoy]

This depends on how you get "White." 200 lm/W is probably the max for broad spectrum white with components in the deep red and deep blue parts of the spectrum. However, an ideal (100% efficient) narrow-spectrum RGB emitter could probably produce almost 400 lumens per watt, and would still appear white.

It'll be interesting to see how good the tint is on the RGB emitters when they start to take over from the phosphor white LEDs. A few years away I guess.

 

[2xTrinity]

It'll be interesting to see how good the tint is on the RGB emitters when they start to take over from the phosphor white LEDs. A few years away I guess.

One big advantage of separate RGB emitters is the possibility for variable tint -- such as the ability to light up a room with bright, cool-white tint for doing demanding work, or low-level warm white for relaxation etc. In the case of a flashlight, independently choosing a tint, or even a single color (such as monochromatic red) could be useful in many situations. Another possibility is that they might go to blue + 2 phosphor (red, and green), as soon a lot of the shift with LED lighting will be lighting that looks good for general use, not just as many lumens per watt as possible. Right now the push for lumens/watt I suspect is being driven primarily by computer/gadget manufacturers and so on for backlighting of devices with la minimum of battery power.