LED infant mortality and mini-review

While this is a global question, I have a specific reference.

What is the general feeling about LED devices being DOA, or dying shortly thereafter? I realize this is a loaded question, and depends on a number of parameters.

Reference example: I've owned and been happy with the earlier Energizer headlight, but had read several good things about the new 6 LED version. Apparently so did the hunters, fishermen, and campers in my area. As a result, the local Walmart's initial supply of three pegs worth was sucked off the shelves immediately.

Instead of driving to a more distant WM, I decided to wait until the local supply was restocked. I subsequently bought one last night.

Imagine my disappointment when, after inserting batteries and putting the switch through its paces, I discovered that one of the paired flood LEDs didn't work.

First dilemma. I'm NOT going to start dissecting a brand new device to troubleshoot. (Aside, I don't know how these things are wired anyway, unless there's a ribbon cable involved). I decided to wait until today to repackage and return the light. Just before I typed this, I was about to stuff everything back in the blister pack. I cycled the switch, and the previously failed LED started working.

Question: Should I keep the light and trust it to continue to work after the exchange period expires, or return it now? IOW, this is apparently a wiring, connection, or possibly switch issue, rather than a bad LED.

Question: This purchase was local. I know that some of you make purchases out of your immediate area, and not necessarily at Wally's place. For instance, there are many references to Target among CPF members, but the closest Target for me is over 50 miles away. With that in mind, how does early device failure influence the question of returns/exchanges. Do you just figure it was only $xx dollars and let it go? I realize there is a magic dollar value, below which it's not worth making an issue of things, and that distances and amount of hassle plays a part. But I'm curious as to where (and when) those magic variables start kicking in.

To add something hopefully of value to the group, by way of a mini-review of this headlight, I must say that both the good and bad points I had read are true:

First the sticker on the package. To quote, "Advanced LED Technology. 2X BRIGHTER than previous Nichia LEDs". Curious phrasing. Does this mean that the prior version had Nichia's and this version does not, or does it mean that this version also uses Nichia's, but that they are just brighter?

1. This light is easily 2x brighter than its predecessor.
2. The slide switch has been replaced with a rubberized clicker; #1 = two spots, #2 = two floods, #3 = spots and floods together; #4 = two red LEDs; #5 = off.
3. One complaint I read was about the red beams being last instead of first in the cycle, due to defeating the whole night vision idea. To that, I'd say, what if it were reversed, with red LED's being first in the cycle? I think it's a no-win either way if a pair of whites come on -after- the red cycle.
4. The spot beams still have the 'owl eye' effect, with rings, artifacts and hot spots. However, the further away the object being illuminated, the less this becomes an issue. No throw distance test made, but they sure blew a lot of light against a wall 15 feet away.
5. The floods are at the extreme edges of the case, and while protected by the 'global' lense, have no magnifying characteristics. Hard to make a judgement on spill (especially with one missing), but there is a definite difference between spot and flood.
6. The red portion is -bright-, but suffers the same effects as the spots, with up/down alignment problems added. This too becomes less of an issue as distance increases.
7. The package clearly mentions "Outdoor" (as opposed to...?). Other comments have mentioned that in spite of the rubberized switch, they would not consider this a weatherproof (as in rain) device. I don't plan to use it in either outdoor or rainy situations, so this is a non-issue for me.

While typing this and exercising the cycles for this post, the same flood LED quit working again. My decision to return has just been made, but the question stands.

Thanks!

Are you referring here to bare LEDs or LED flashlights? That makes a huge difference. Let's talk first about bare LEDs. As with any electronic component, the lifetime versus number of samples plot is a bathtub-shaped curve. A very small percentage of LEDs won't live very long due to manufacturing defects. Hopefully once testing in the factory improves this number can drop to essentially zero. As it is it's a very small number. The majority of LEDs which don't die in infancy will go on to live long, productive lives, with an ever increasing percentage dying as hours of operation increases. Finally, as the LEDs reach their rated life, the number of failures will start to go dramatically up. Practically speaking, LEDs will usually dim past the point of usefulness long before they actually fail completely. A Luxeon rated for 70% lumen maintenance at 50,000 hours might well "work" for another 500,000 hours, for example, but much past about 100,000 hours it won't be giving much useful light.

Now let's look at LEDs incorporated as part of a flashlight. Here again we have the same bathtub-shaped curve, but a failure of any part in the flashlight means that the flashlight has died. Statistically then the percentage of infant mortality will be much higher than for bare LEDs, although still probably well under 1% for a properly designed flashlight. If a much greater percentage that that fail, I submit it is from poor design/quality control rather than from only the LED itself. As an electronic component LEDs as very reliable if used properly. Overdriving, poor heat sinking, voltage spikes all contribute to early LED failure.

hawk said:

Question: This purchase was local. I know that some of you make purchases out of your immediate area, and not necessarily at Wally's place. For instance, there are many references to Target among CPF members, but the closest Target for me is over 50 miles away. With that in mind, how does early device failure influence the question of returns/exchanges. Do you just figure it was only $xx dollars and let it go? I realize there is a magic dollar value, below which it's not worth making an issue of things, and that distances and amount of hassle plays a part. But I'm curious as to where (and when) those magic variables start kicking in.

Click to expand...

Simple solution.... test it in the parkinglot Well, flashlights and stuff like that... when you go buy a new washingmachine its different... I even installed the radio in my car across the street from the store where I bought it (and as it is an older car, it's not exactly plug and play...)