negatives to "snow" LEDs ?

I have been very impressed with my Peak Snow Hi-power 3 LED.

It seems to me that they make all the Nichias obsolete, in beam quality, and in color.

Do they have shorter life by any large margin ? Any other negatives ?

When I use many of my older lights, the blotchy, multi-colored beams pale in comparison.

I have seen others wondering about that. I am thinking of going with the 3 LED high power Matterhorn instead of the 1 LED ultra. More light with the LEDs driven less hard and hopefully longer use without degrading.

JohnK said:

It seems to me that they make all the Nichias obsolete, in beam quality, and in color.

Do they have shorter life by any large margin ? Any other negatives ?

Click to expand...

The Snow29s have a much nicer beam quality, however, their lifespan compared to a Nichia depends on how hard you drive them. See the third post of this thread to see how well they hold up at various currents.

Paul

83Venture,
That was my thinking with my Snow29 Matterhorn 3 LED version. I wanted the most efficient drive live so selected the standard drive level. As with Luxeons, the most efficient level is generally around the stock level or even lower. Luckily, the regular Matterhorn has 3 LEDs that operate independent from each other. In the rare case an LED blows, the other two light up normally.

Still waiting for the Peak Luxeon "1 watt" AAA series, the life should be close to forever considering that it won't get close to stock drive levels. My Lambda MicroIlluminator is a single AAA Luxeon light that runs the LED at 155mA. The potted curcuit board sandwich is enough for it to stay cool and it will probably last forever. If Peak rolls their AAA Luxeon, it should be in that range so comparing a Snow VS Nichia VS underdriven Luxeon chart would be close to impossible. 175mA Luxeon at 37,459 hours is 99.13 % and still going....

The longest I have run my standard snow is around 15 minutes. The lithium AAA powered light did generate some heat as the head felt a little warm. My original lithium AAA is still strong after a month and a half use without dimming so the Snows generally never run long enough to every have detectable heat. Normally, the light runs in the range of 15 to 60 seconds so I don't think I will live long enough to see it start to become dim.

Chimo is right - they don't like being driven at 40mA very much. For better or worse, that's mitigated by the fact that when running under 2v, they're apparently not being driven at that rate for very long. They would likely last longer when driven in short bursts - as they are in "real life" - but no testing has been done to know to what extent. (smirk) If someone figures out a convenient way to test it though, we're all keenly interested in the results.

You'll have to determine how you're going to use your light to determine if the output reduction is a concern.

If you'll use the light for short periods and/or with alkaline batteries, the output reduction may never be noticeable. If you're going to use it for long periods at a time, and especially if you run Lithiums, it may be a factor.

For example, a couple weeks ago I used my Arc AAA with Lithium battery for a dim room light a few evenings in a row. With usage like this or as a tent light while camping, it wouldn't be difficult for me to put 15 or 20 hours of use on the light in a week. This combination of higher drive current and lots of run time would likely guarantee diminished output over a few such uses.

Arch,
There is a way that normal use can be simulated. Take a programmable power supply that will hit the Snow for 2 minutes at 40mA then shut off for 8 minutes. During the off period of time, have a 100 CFM fan blast the head with room air through a funnel to cool it rapidly down to simulate hours of off time.

On for two minutes, off and blasted with strong air stream for 8 minutes to cool... on for two minutes... off for 4 minutes in strong air stream to cool it for 8 minutes. Over 24 hours, it will be on for 4.8 hours. 6 weeks later you would have 200 hours of on time and the results would be much more accurate. I am not aware of anyone that is bored enough to build and monitor such a test device though.

Once the Luxeon AAA Peaks come out, my Snow Matterhorn will be on my wife's keychain... she will go through a battery every couple of years so.... Personally, I will follow the Nichia to Snow to Snow29 to Luxeon upgrade path.

I am fully aware that 5mm LEDs can degrade at high current (as ALL LEDs do), my real question is that at 30 mA levels, is there any SIGNIFICANTLY increased degradation, compared to a Nichia at the same current.

I do doubt that I will put more than infrequent use of the light anyway. Hundreds, and hundreds of hours of use occur very rarely.

With a zillion lights, if I used them all that way, I'd have to quit sleeping to fit in all the burn time.

Regardless, I am SOLD on the "snow" LEDs. If you haven't seen them, you will be in for a pleasant surprise. Let me rephrase that, you will be in for a HUGE surprise. A very large jump in quality.

Absolutely beautiful beams, in smoothness, and color.

I have also run lumen maintenance tests on the "snow" LED (ETG) and found it to have reduced endurance compared to the Nichia parts, even when run at less current than the Nichia. I can post my results if required.

There are several new LEDs on the market that provide nice beams but have a significantly reduced lifespan.

Peter

Peter,

I was wondering if using E91/92 lithium AA/AAA batteries in Arc flashlights will have any detrimental effect on the life of the LEDs?

Peter, I would be happy for you to post your tests.

I do know you have a dog in this fight, but I will assume you will be impartial.

If the moderators will lead me in this, I will follow.

I don't have a dog in this fight, I just like nice white, bright LEDs.

Simple as that. I like my ARC too.

Gransee said:

There are several new LEDs on the market that provide nice beams but have a significantly reduced lifespan.

Peter

Click to expand...

I find it hard to believe that a nice beam and a long lifespan are mutually exclusive. Perhaps it is just a matter of time. Peter, I hope you find a robust LED with a nice beam to use in your next effort. When you do, I will surely get it

Solstice said:

I find it hard to believe that a nice beam and a long lifespan are mutually exclusive. Perhaps it is just a matter of time. Peter, I hope you find a robust LED with a nice beam to use in your next effort. When you do, I will surely get it

Click to expand...

agreed

Test parameters:

4 LEDs were tested, 2 Nichia NSPW500CS UB2 and 2 ETG/Cree 15degree "snow". In all tests, the Nichias were run at 60mA while the Crees were run at 30mA. The LEDs were mounted side by side on a PCB within 1 inch of each other. The entire rig was placed in a plastic enclosure to reduce any air currents over the test fixture.

The current levels were selected for these reasons: The current the LED is driven in either flashlight varies depending on items such as regulation scheme used, vf of the LED, battery voltage, temperature, etc. For the Arc-AAA, it averages about 45mA to the LED for both the Premium and the Standard versions. In some cases, this may be higher and as the battery voltage drops, this current will drop as well. I decided to use 60mA so as to make the durability of the LED we use in the Arc-AAA very clear and easy to understand. The 30mA for the Cree LED is a guess really. To my knowledge, Peak continues to keep that data to themselves. My observations of the few units I have seen show a wide current variation from to unit. Some could be only running at 25mA while others are over 40mA. Nailing this down is not my responsibility. I selected 30mA to serve as an example of how the LED would perform at a typical current for this type of flashlight. Even if Peak chose to publish a current spec, the best I could think they would be able to do is to provide a wide range of possible currents for a particular model.

Two tests of 2 LEDs each were run. The test fixture utilized a precision power supply feeding dual current regulators each driving an individual LED. LED output was measured using a CDS cell in series with a common power supply. For the second test, the LED brands were swapped in the test setup to factor out any variations in the test rig.

Remember, the response of a CDS cell is logarithmic. That means the differences between the plots are greater than what they might first appear.

Since the LEDs were tested in pairs, any variations in ambient temperature, power supply drift, etc should be normalized between both LED measurements.

This graph was generated in excel. Although the original plots were separated by differences in brightness between the various LEDs, all plots were normalized to the same start value to show relative changes more clearly. Remember this when you read the graphs. And as always, if you doubt the data, test it yourself.



Your comments are welcome of course.


Piper: Yes, using a 1.7v lithium will reduce the lifespan of the LED in both flashlights. However in the Arc, we have tested the effect of the lithium on our system and do not feel it will make an appreciable effect. We will continue to offer our standard replacement guarantee.

Solstice and others: I also want better LEDs. 200lm/w, perfect color coordinates, infinite lifespan, etc. In the meantime, I will find the best for my goals and use those.

Btw, not trying to stir up controversy or anything. The snow LED does provide some benefits. It is nice that the customer is free to decide what is important to their particular use. The lights I design are not for everyone. That means, not everyone is going to like them.

Peter

Thanks for the detailed reply Peter. Nichia seems to really have it down when it comes to making a durable product. Hopefully, something with better phosphor distribution (if that is the culprit behind the Nichia blue beam) is in the pipeline from them.

As far as the Arc AAA is concerned, I actually believe it is a superior product on most fronts.

As you have said yourself, the Arc AAA comes as a compromise that accomadates a vast spectrum of possible uses, and in most cases it's lumens and durability that matter over beam quality.

Personally, I'm fine settling for less than perfect efficiency and infinite lifespan from LEDs, its just that after seeing the nice white tint that other LEDs are capable of (underdriven Luxeon included), I would figure that Nichia could match the technology while perserving durablity.

I would prefer a nicer beam even at the cost of some efficiency/brightess in a small AAA light, but that is just one user's perspective.

Maybe a little down the road if you find an LED durable enough you could put out a less bright version with a better beam called Arc AAA QB (Quality Beam) or Arc AAA CU (Close Up)... Arc AAA TW (True White)...Arc AAA...I could come up with these all day .

Its all relative. Nichia for now is a better design compared to the Snow LEDs in terms of durability. But Compared to high-outputs like Luxeons, Nichias are in the stone age (MUCH shorter life, inferior tint--never seen a nichia that doesn't have an angry tint in the hotspot, inferior beam).

I have no reason to buy nichia based leds, the tints are awful for a white led my opinion says, and the beam pattern leaves a lot to be desired. With led technology the way it is, one CAN make a small luxeon light that runs off 1 AAA or 1 AA light.

Its good to see this finally begin to happen, with Peak making the Kino Bay 1AA and other companies stepping up to the plate as well. Those that still use Nichias are using inferior technology my opinion says.

Although a luxeon can be attached to a dc/dc converter and a 1xAAA cell, its not a free ride. Either the total package size is increased or the optics suffer. Sometimes both.

I have seen some pretty good AAA luxeon designs. I have a couple sent to me that are the same size as the AAA and produce a focused beam. The beam has a lot of artifacts in it and the optic are difficult to manufacture consistantly (these were hand made). These are all surmountable of course given enough time.

Although some units use a 3.6v lithium ion cell, I am only interested in a unit that runs on a common AAA.

Peter

I agree with the use of a common AAA- that's partially the point of these lights; that they are cheap to run and easy find batteries for. I wouldn't be interested in anything using a special type of AAA battery.

As far as AAA luxeon designs, I wouldn't mind it if the beam was practically unfocused (flood) and if the luxeon was drastically underdriven to achieve a decent runtime. I have the Jil DD (yes, I know its not the same as the Jil uses a 3 volt battery), but I find the amount of light it produces, while not being a flamethrower, is just fine- ideal, in fact, for close up work like reading.

Yes, I have seen a few luxeon aaa mods that have a wide flood beam. Although the lumen values are pretty good, the beam is not as useful for medium range use. An ideal EDC must be able to operate at common distances for everyday use. The Arc-AAA is not ideal, but I certainly don't want to make it worse or less balanced.

Peter

I get your point about that (and the current Arc AAA does a surprisingly good job at middle range), I guess I'm just too much of a flashaholic in my thinking: I figure a small keychain light will be mostly used for closeup work or when *some* light is needed (general navagation, etc.). For anything farther away, I'll use a bigger light (currently a Fenix L1P- gotta love those common batteries).