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Thread: Any LED Problems?

  1. #1
    Flashaholic*
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    Default Any LED Problems?

    I've posted that some of my LED lights have lost intensity while consuming more current. Has anybody had LED problems, such as: color shift, bad circuitry, blown LEDs, dimming, heat, intermittant operation or other abnormalities?

    My experience, so far, is that LEDs are more reliable than incans, but have their own quirks, too. Not owning LEDs for very long, I'm less familiar with their failure modes, compared to incans.

    What are your experiences?

  2. #2
    Flashaholic flashlite's Avatar
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    Default Re: Any LED Problems?

    There was a long thread on this a few month ago....how LED's might last thousands of hours but brightness & efficiency would diminish relatively quickly compared to the life of the LED. I was so gung-ho on LED's until I read that thread. I still like LED's because of the long run times but I won't spend big $ on a LED light until there are some advancements in this technology. Unfortunately, the only recent advancements are brighter LED's at the expense of long run times. LED's are losing the biggest advantage they had over incans.

  3. #3
    *Flashaholic* idleprocess's Avatar
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    Default Re: Any LED Problems?

    LEDs beat most other light sources in the low-power arena. They don't scale up to high power as well as most other lighting technologies.

    Good thermal design eliminates most issues with declining output - heat is the killer of solid-state electronics. Not surprisingly, overdriven LEDs decline quickly if thermal management is average or poor.

  4. #4
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    Default Re: Any LED Problems?

    I have not blown any LED lights yet, been trying. There are a few ways to increase the life of your LED lights and as idle stated, heat is the killer.

    If you are using 5mm LEDs, get flashlights that don't overdrive them. The top dog of most overdriven is the Streamlight 4AA 7 LED light...those LEDs hum along at 70-80mA for each LED! Considering that white 5mm LEDs don't like much past 20-25mA each, stay away from that one.

    The beloved Arc AAA overdrives the LED at 40-45mA which reduces it's life but boosts the output. If that bothers you, the Peak LED Solutions AAA light would suit you. It runs at 23mA for the regular and 30mA for the "high power" version. The good thing about the Arc/Peak is the LED is potted in the curcuit so it dumps heat faster. That cooling effect should help their life.

    For me, the 5mm AAA/AA lights are just a stop gap for Luxeon versions. The Arcs will be loaded with lithiums and dumped into an emergency box when the Lux's arrive. Luxeons also need to be kept cool as they generate 1.25 to 5 watts of heat. My BB500 R2H burps along overdriven at 1.6 watts but I have taken steps to cool it down.

    Locking the head down with lock-tite allows a better thermal path to the thick aluminum to cool it down. The regulator overdrives it but also keeps it from being waaaay overdriven also. The one on my bicycle helmet has a brass carrier it mounts on and that helps with cooling. The other bonus is the light is being cooling by moving through the air at 13 to 20 MPH so it never overheats.

    If I want to run a Lux LED light for a long period of time, the good ole' Mag 2D mod cools the LED very well. In still air, the Lux heatsink is 12F above ambient room temp and that is with the head removed. Can't get much better than that.

    One of the good things about building your own mod is the bin code of the LED can be selected. The lower voltage bins generate less heat and if your output bin is high, it will generate more light. My MicroIlluminator single AAA light runs underdriven at 155mA (stock is 350mA) it uses the ultrabright R3J bin to run at a lower voltage (J=3.28-3.50 volts) coupled with the high output of the R bin, it is almost as bright as a "normal" Luxeon but generating almost no heat.

    If it makes you feel any better, my overdriven Luxeon minimag has been lighting my way for a year now with no noticable drop in output (compared to my other minimag BB500 R2H) It has gone through about 15 sets of alkalines and I have recharged my NiMH AAs about 5 times.

    If you want to get a cool running, small, underdriven Luxeon light with variable brightness (it will run even cooler then) Peak is going to be producing single cell AAA/AA Luxeon lights by the end of the year. No more overdriven 5mm lights, get an underdriven Luxeon and don't worry about it until 2104.

  5. #5
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    Default Re: Any LED Problems?

    Anyone know the normal lumen range of a normally driven 1 watt luxeon LED? Is it 20 or so lumens? I'm curious because there are 40-60+ lumen 1 watt LEDs that I assume are overdriven. The Pelican M6 LED (41 lumens) and LedXtreme Predator (60 lumens) seem way too powerful to be driven to specs for a 1 watt LED. And since I own both models, I was curious as too how much these lights are overdriven. They both seem to have good heat sinking, but I'm betting that the LED life will be short on both relative to 1-watt LEDs driven at lower levels?

  6. #6
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    Default Re: Any LED Problems?

    Hello i also have had LED problems in my case i find all green
    LED lights I have owned Inova XT-5 snd other small green no name LED lights have horrible black hoiles in the middle of the beam along with other numerous defects. My question is can
    I buy a KL3 GREEN LED HEAD and use it with a surefire p6 and get a decent beam for night walking .( this light is for my mother-in-law to be and i want to give her something nice for her birthday [yes, she is a senior an a real sweetheart thanks ahead for any and all suggestions
    william a.k.a. FLASH99DARK --a newbee [img]/ubbthreads/images/graemlins/icon3.gif[/img]

  7. #7
    Flashaholic*
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    Default Re: Any LED Problems?

    Welcome to the CPF flash99. I just got an X5T and am pleased with its smooth, bright, beam. Your's seems to have a problem not mentioned before. Can you get warranty service on it, because your description doesn't sound normal for that light?

  8. #8
    *Retired* The_LED_Museum's Avatar
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    Default Re: Any LED Problems?

    Most flashlights using red, orange, amber, yellow, green, blue-green, blue, and violet LEDs will tend to show various artifacts and other beam "defects" generally not found in white LED products.
    This primarily applies to products using 3mm and 5mm round LEDs, not Luxeon LEDs.

    There is little that can be done other than using a satin filter over the head, such as Write-Right or Scotch magic tape.

    My 2¢ here; individual results may vary.

  9. #9
    Flashaholic* Sub_Umbra's Avatar
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    Default Re: Any LED Problems?

    [ QUOTE ]
    flash99dark said:
    Hello i also have had LED problems in my case i find all green
    LED lights I have owned Inova XT-5 snd other small green no name LED lights have horrible black hoiles in the middle of the beam along with other numerous defects...

    [/ QUOTE ]

    Funny you should mention that. I am very fond of green lights and that's what I invariably grab unless there is a compelling reason not to. In the last couple months I ordered some colored CMG Infinities on closeout before they all disappear. The green one had a HUGE hole in the center of the beam. It is still usable but I was bummed because of the four colors of Infinities I ordered, I was most excited about the green as it is so handy.

    Anyway, yesterday I received two old green 'tinned' Infinities from the Battery Station CPF Special page and they both have pretty nice beams. Great price too, at $12 ea.

    You may look into the NightCutter Sport in Green. I have the 3-Green and 5-Green heads and they are both very usable. I use the 5-Green head all the time. The prices on the NightCutters can't be beat.

    I have also been very happy with my old Tektite Trek-2 GREEN. I have used it for years.

    Good luck

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