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Thread: U2 Ultra 80/100Lumen.

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    Flashaholic* ZeissOEM2's Avatar
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    Default U2 Ultra 80/100Lumen.

    edit
    Last edited by ZeissOEM2; 08-26-2007 at 10:40 AM.

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    Default Re: U2 Ultra 80/100Lumen.

    it's generally acepted to ignore lumen claims. Surefire is pretty conservative.

    luxeon lottery will determine how bright you light is. original release U2's seems to get the highest number of feedback from folks claiming their U2 is Xbin bright or very close.

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    Default Re: U2 Ultra 80/100Lumen.

    Mine is a serial number in the high AO3000s. Box says 100 lumens. I'm not sure if that means anything or not. I'm happy with it and although still curious, have not been dwelling on it. I've never seen a "definitive" answer, either. Just some good speculation.
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    Flashaholic* powernoodle's Avatar
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    Default Re: U2 Ultra 80/100Lumen.

    My AO8047 (new) is very bright and white, and to my eyes out throws and outfloods my Gladius. Cy is right about the numbers, but I'm impressed with mine whatever the number.

    best regards

  5. #5

    Default Re: U2 Ultra 80/100Lumen.

    I contacted Surefire on this exact topic because between my U2 box and their website you get two numbers 100 lumens, and 80 lumens. They told me that the correct output is 80 lumens. The 100 might be a bulb lumen while the 80 lumens is what you actually get coming out of the front of the flashlight? Surefire claims that they get 80% of the light from the bulb out of the front of the flashlight so those numbers would make sens if that was the case, oh well its a great light regardless.

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    Default Re: U2 Ultra 80/100Lumen.

    Hello everyone.

    I just got bit by the flashlight bug (again) recently and I was thinking about purchasing a U2 as my EDC. I was wondering about the 80/100 lumen thing especially since the L2 according to the Surefire website is rated at 100. Unless I'm wrong (please correct me if I am) they both have 5w LEDs. Is it that they are just more conservative with the more premium model? Were they rated at 100 and they changed it? Are the new ones just as bright as the first ones?

    Thanks for any feedback.

    Steve

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    Flashaholic* Sean's Avatar
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    Default Re: U2 Ultra 80/100Lumen.

    Quote Originally Posted by Steve77
    Hello everyone.

    I just got bit by the flashlight bug (again) recently and I was thinking about purchasing a U2 as my EDC. I was wondering about the 80/100 lumen thing especially since the L2 according to the Surefire website is rated at 100. Unless I'm wrong (please correct me if I am) they both have 5w LEDs. Is it that they are just more conservative with the more premium model? Were they rated at 100 and they changed it? Are the new ones just as bright as the first ones?

    Thanks for any feedback.

    Steve
    It varies from unit to unit. They both use 5W emitters, but 5W emitters come in these grades:

    V................113.6 lumens to 147.7 lumens
    W...............147.7 lumens to 192.0 lumens
    X................192.0 lumens to 249.6 lumens

    These numbers don't seem to be what you actually get (seems like you get less), but the range still applies. Higher bin number = brighter LED. So brightness depends on the bin you get and the power it is driven at. The L2 for instance is driven harder than the L4. So the L2 is brighter than the L4 but the battery life is shorter. Also, some people have a really good bin luxeon 5 in their L4 and a not-as-good bin luxeon in their L2 resulting in nearly equal brightness.

    So what does all this mean?
    It means that you should get at least 80 lumens out of these, and if your lucky, more. Surefire is basically under-rating them in general, because you never know what bin luxeon your going to get.
    Last edited by Sean; 10-13-2005 at 08:07 PM.

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    Default Re: U2 Ultra 80/100Lumen.

    I just got my U2 AO6875 tonight. Played with several U2s at the dealership since they allowed me to choose one. After picking one up, compared it to the Gladius at the same store. My U2 seems to outshine and outthow the Gladius and has a whiter light.

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    *Flashaholic* wquiles's Avatar
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    Default Re: U2 Ultra 80/100Lumen.

    No offence intended, but the Gladius has a 3W while the U2 has a 5W. Hard to compare between the two. Almost like apples vs. oranges

    Will
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  10. #10
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    Default Re: U2 Ultra 80/100Lumen.

    Quote Originally Posted by cy
    original release U2's seems to get the highest number of feedback from folks claiming their U2 is Xbin bright or very close.
    That was one of ZeisOEM2's questions. Namely, WAS there truly an initial batch that got better emitters, or is it merely speculation?

    My A07416 has tremendous output. Using a lux meter to measure the reflected light and comparing to my HDS U60 (which is calibrated to produce 60 lumens on max), my U2 produces roughly double the overall output. That implies at least 100 lumens.

    Don't know if that's average or above average. Unfortunately it has a significant doughnut beam pattern so all isn't perfect.

    Comparing overall output by looking only at the hotspot is tricky since much of a light's energy output is in the dimmer (but much larger) spillbeam. The U2 in particular has a very bright spillbeam, so it has more overall output than may first appear obvious.

  11. #11
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    Default Re: U2 Ultra 80/100Lumen.

    I don't think the early batches necessarily got better emitters. I got a very early s/n U2 with a hugely underperforming LED. It improved a lot when I replaced it with a WWOT LuxV.

  12. #12
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    Default Re: U2 Ultra 80/100Lumen.

    Quote Originally Posted by joema
    That was one of ZeisOEM2's questions. Namely, WAS there truly an initial batch that got better emitters, or is it merely speculation?

    It's purely speculation, no-one has any figures for the U2s output from the early or newer models.

    Most (if not all)of these claims are of the "it looks as bright as this other light i have which contains an X bin" variety, and binning a LED by eye alone is not the most accurate method.

    **Edit** Someone DID manage to put an early U2 in an integrating sphere, and got a figure of around 113 lumens. So if they are indeed X bins, the U2's reflector is around 50% efficient, which i find highly doubtful.
    Last edited by kakster; 10-15-2005 at 07:56 AM.

  13. #13
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    Default Re: U2 Ultra 80/100Lumen.

    From the charts, a Wbin is rated 147.7 - 192.0 lumens, while an Xbin is rate 192.0 - 249.6. How hard must the LED be driven to achieve these ratings?

  14. #14
    *Flashaholic* wquiles's Avatar
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    Default Re: U2 Ultra 80/100Lumen.

    Quote Originally Posted by seattlite
    How hard must the LED be driven to achieve these ratings?
    That is the rating when driven at the spec. current (700mA or 750mA - don't remember exactly which one). The range is failry wide due to the "Luxeon lottery" since it could literaly be all over the place. You could in theory have a high performing W bin and a low performing X bin and to your eyes they could look the same since the human eye can't detect very small lumen changes.

    If you drive them harder, they will of course get brighter, but they would not be as efficient. If I recall correctly, to get an LED 50% brighter you had to drive it twice as hard, plus this would severely diminish the LED's life.

    So again, in theory, you could perhaps drive a W bin to 1000mA or 1.5A and it could look as bright as an X bin driven at spec (say 750mA), but it would get much hotter and would not last as long

    Will
    Last edited by wquiles; 10-15-2005 at 10:45 AM.
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  15. #15

    Default Re: U2 Ultra 80/100Lumen.

    Quote Originally Posted by kakster
    **Edit** Someone DID manage to put an early U2 in an integrating sphere, and got a figure of around 113 lumens. So if they are indeed X bins, the U2's reflector is around 50% efficient, which i find highly doubtful.

    I've never measured the drive current at level 6 but given the fact SF tends to underdrive a little, it may still be Xbin and underdriven. (A little underdrive will probably lower their cost due to emtters burning out and having to be replaced)

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