LED Efficiency

[dave]

I know that LED's have a very high cool factor to them but what is the real Efficiency. Seems to me that they are very overrated because when someone thinks about LED's they think very bright last forever on one set of batteries.
They last because they don't brake but with the 500 hour LS out even that seems its going away
And with LED's so expensive it seems like
It's not worth it and when you look at fluorescent bulbs they blow LED Efficiency
Away even some incandescent bulbs are on
Par with LED's so are LED's worth it
Or is it all just hype!!!?

 

[Icebreak]

dave-

I'm still kind of a newbie here. My take is this: CPF is a group of forums driven by a great couple of creators, and thousands of people with a natural primal instinct to have a good torch. A "good" torch is user defined. The LED forum, IMHO, is in fact driving technology. Case in point: Surefire.

One question you posed was about the effiency. For me, nothing touches an LED light for close up work. If I am working on a small object, let's say the connections in a computer, I'm going to use an LED. Recently I got contacts. They are a pain for me but they are such a fine thing, I use them anyway. To put them in I use a weak LED pointed at an angle to my eyes. Nothing works as well for me for either application. I am now in search of the best handheld royal blue light available for special purposes. I wish Mr. Bulk would give me his or another modder would build one for me. I was reminded by one of the old guard to have some fun searching for and finding a fine light that I will not only be the first one in my neighborhood to have but likely, the only one in my neighborhood to have.

I know that eventually LED flashlights will serve many of the functions of user defined "good" torches. I will admit that I get irritated with the pace of the progress. I get sick of the fact that luxeons can be puke green or purple. But some of them are just right. I think that for this moment in the progress that multiple nichia bezels are the way to go. However, there are hundreds of folks here that will disagree. I love that. They are driving technology. I get irritated that manufacturers can't come close to what the modification experts here can build.

But man, this is a fascinating time for mankind in the area of personal torches. Yes, that sounds high minded because it is. A good white LED flashlight will illuminate the forest with full moonlight-like light which I've learned by reading this forum is good because it won't blow away a person's night vision. Another may last for days during a power outage. Other specialized LEDs may solve a medical riddle or a crime or purify food or treat a medical condition.

There is one particular light built by ARC that proves that an LED light is an incredibly valuable thing to have. I'll let one of the more experienced CPFers speak about it. I see that you have been registered for a year and a half so you may already know about it. Since you've been here a while I would respectfully submit these humble recommendations. Take your shoes off. Set a spell.

Great question.

-Jeff

 

[Rothrandir]

personally, i like leds because of the coolness, rarity, life, durability, color rendition, effency, and mod-ability. fluorescent are more effecient, but how many fluorescent flashlights do you see? leds are not generally as bright as some other photon creating devices, but the are ultra durable, and last extremely long. and as a result of the extra light life, the bodies of the flashlights can be made stronger and more waterproof.

 

[carbonsparky]

Leds have their place. I have a Energizer Arc Light that works great for creating a nice field of light around the flashlight. I have a Legend LX That eats about 7-1/4 watts of power out of the batteries, can light up the far side of a basket ball court. I have a First Alert 500,000 cp gel cell lantern' good for about 3 hours of use between charges. They each have their place.
My main LED light lives on my key chain (Micro Photon 2). The white light produced by it is more effective than a mag solitaire and it is smaller and lighter.
A 1w LS is a fair match for a Mini-Mag but produces a whiter light and it does not get silvered like the maglight's bulb does. Its light stays pretty much the same color even when the batteries are low.
As for life time of LEDs it is hard to beat even the 500hr 5w LS's. Most flashlight bulbs are good only for 10 to 15 hours.
Cost is going to come down once the bugs are worked out and more manufacturers step in. The level of improvement is incredible. My old Radio Shack dims produced a dim almost useless light at 20 mA, now with the same amount of power we are seeing up to and exceeding a thousandfold increase in output.
For me, I have been in love with LEDs since I bought my first assorted pack of dim rejects from Radio Shack back in the 70's. There is something neat about light that works by passing current through a solid.

 

[Jonathan]

The best _white_ leds, run at full power, have 'efficiency' that is pretty similar to the best halogen lamps run properly. By 'efficiency' I mean 'lumens per watt' or visible light output versus electrical input. I am putting quotes on efficiency because it isn't a proper power output equation, but instead a comparison based upon some other measure of usefulness.

Anyhow, many other light sources (compact florescent, HID, etc) are considerably more efficient than LEDs.

But LEDs have several aspects that make them kick a** in many situations.

1) LEDs are efficient in much smaller packages. The best 0.15W LEDs are about as efficient as the best 10W halogen lamps, and are _much_ more efficient than 0.15W halogen lamps. I don't think that 1W 'florescent' lamps are particularly efficient, and as far as I know LEDs pretty much rule for efficiency below 1W.

2) LEDs get _more_ efficient when they are underdriven. This means that you can efficiently run an LED at fractional power levels, something this pretty much isn't true for any other common light source. Halogens _suck_ when dimmed, and you need very special florescent for dimming capabilities, and I'm pretty certain that they loose efficiency when you do this.

3) As a consequence of 2), LEDs are more effective when you have a power source that gets used up, eg. batteries. When the voltage drops in an LED flashlight, the light gets dimmer because the LED is getting less power. When the voltage drops in an incandescent flashlight, the light gets much dimmer, because you have the compound problem of less power _and_ lower efficiency.

-Jon

 

[RonM]

I love LED lights and use them 5 to 1 over my incadescent flashlights. However, I do sympathize with your efficiency complaints. I guess certain LEDs are quite efficient, but that's in the lab. Doesn't efficiency go out the window once we insert dropping resisitors, voltage regulators, step-up circuits, etc. into our lights? The problem is that white LEDs don't seem to like voltage increments available from standard alkaline batts.

Still love my LEDs though! Go figure.

 

[Brock]

Most of these points have been mentioned but here are some of my reasons for liking LED's.

The most important first, they don't yellow as the batteries die. I can't emphasize that enough. I hate a flashlight that "yellows" after the batteries are 10 minutes old. I know regulation will help out incan's here, but not yet, and certainly not in this size.

The are extremely tough, you can literally throw them around without worrying about breaking the "lamp".

They are really small. There is no way you could get a light the same brightness and size of a Photon 2 or even an Arc AAA, at least not with a similar runtime or relatively flat output.

 

[dave]

Thanks everyone for you opinion
I think LED's Are just to cool
and easy to make mods and Well
that's why I keep buying them
they Need to make AAA meeting
for LED's LOL!!!!

 

[star882]

Florescent lamps still win in the race for efficiency, but LEDs are right after.
LEDs are nice for high endurance.
Read Chris's review for the CCFL light.
You will see that it was damaged when he dropped it, the LED lights are tougher and are harder to break.

 

[INRETECH]

Although a Florescent light is more eff than a LED, there is still a lot of energy wasted in the ballast and the process of converting electrical energy to light energy in all but LED and HPS is a destructive process

Every light source has its own pros and cons; Except for the LED - the more eff a light source is the more difficult it is to dim or control

Mike
www.inretech.com

 

[Charles Bradshaw]

There is another kind of efficiency: most efficient use of batteries! LEDs are useful far below the voltage where you change batteries in incandescent lights.