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  1. #1
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    Some XML Lumen figures for you

    I just got some early results in from the lumen testing lab

    I sent a single XML with Laura lense and driven by a Lflex. set at 3amps
    and a triple XML with cute ss optic. driven by a H6Flex. at 3amps



    Lumen:
    Magicshine (reference): low = 185, high = 500
    single XML: low = 110, med = 550 high = 900
    triple XML: low = 260, med = 900, high = 2800

    For the single, 3.71V was supplied, current drawn was 0.24A, 1.30A and 3.08A
    respectively.

    Note that on high the values were dropping rapidly over the first few seconds.
    The measurement is taken at about 10 seconds after switching.
    It takes this long for the meter to auto-range and stabilize.

    Peak Lus at 1m distance:
    Magicshine (reference): 1430 and 3700
    Single XML: 760, 3580, 5900
    Triple XML: 1180, 4015, 13000

    Again on high the values were dropping. Measurement after about 10 seconds.
    The room temperature is controlled to 24C.

  2. #2
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    Excellent stuff!

    Is that the new XML MS?

    I think 3 minutes is a good timespan for the innards to warm up (with fan on).
    DIY LED Bike Lights:
    A few Dynamo builds and some Small battery lights

  3. #3
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    Quote Originally Posted by znomit
    Excellent stuff!

    Is that the new XML MS?

    I think 3 minutes is a good timespan for the innards to warm up (with fan on).


    Just come back from vacation have I missed something (XML MS???)

    the leds were XML T6 S2

    Chris the tester who does this for his job and has just been approached by a couple of mags to test lights for next season said these were his first test results and will be doing some more testing to confirm so will post his findings when they arrive .

  4. #4
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    Quote Originally Posted by troutie-mtb
    Just come back from vacation have I missed something (XML MS???)
    XML MS.
    DIY LED Bike Lights:
    A few Dynamo builds and some Small battery lights

  5. #5
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    Thanks Znomit

    no it will be the old P7 MS Bastid used as a reference

  6. #6
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    It's nice to know that my tripple XML is kicking out around 2800 lumens...
    Get in there

    Thanks for the figures Chris

  7. #7
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    ramble notes...
    at 3.71V x 3.08A was that with driver ?
    that would have been ~3.4A at LED, since the xml does 3.14V ,
    and barely gets to 3.2V .
    for continuous use, the XML is good to 2A, at 2.5A it already looses efficiency big time,
    just generates more heat than lumen.
    the thermal junction is rated for bare LED, mounted directly in heatsink,
    while all XML's come on a alu star, with isolation layer, so thermal junction is probably double.
    did a test recently , with 2x xml, c-bin, an lfex, at 2A set,
    with my Bender-box ( lux x pi x my thumb) it gets 1050 bender lumen,
    at less than a minute , start. per my bender calc, it gets 974 lumen.
    that's less than 500 lumen for 1x xml at ~2a.
    one guy in germany did a lumen test at the university, with a T5 bin,
    at 3000ma, at 80C junction, mounted on a big heatsink, did about 75 lumen per watt ,
    about 770 lumen.
    to get to 2800 lumen , within spec, and sustainable, would say need at least 4 xml's.
    ---
    if the led got 3.71V * 3.08A ... (no regulator) be around 78 lumen per watt after 10sec.
    for worst case, at 2A crappy star board, 100C junction, I'd be around 87 lm/W .
    for cooling, running hot, still need 2 sq inches surface per watt, while a good design is
    over 8 sq inches per watt with natural convection cooling.
    anything below 2, be limited by the thermal protection of the driver, and the LED be already cooking.
    non the less, troutie is delivering one of the brightest mtb lights in a decent fashion.
    thumbs up !
    in practical therms , anything over 1500 real lumens, on a handlebar, plus a helmet light,
    is decent enough for single track, as not to fall for the upgrade envy.
    just my 2mah , ehm lux, cheers, Rob

  8. #8
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    Some more data just in from the Lumen Lab

    single XML T6 and Laura optic driven at

    out the front lumens

    3 amps 905 lumens
    2.5 amps 840 lumens
    2 amps 780 lumens

    ---------------------------------------------------------
    Triple XML T6 - Cute SS optic driven at

    3 amps 2883 lumens
    2 amps 2290 lumens

  9. #9
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    thanks for the info Troutie. I'm surprised that the lumen values are so close to the theoretical output of the bare LED (from the Cree datasheets), I would have expected a larger loss. Didn't you see that with your previous lumen readings from your 6 LED (XP-G?) light? I wonder if it's down to plain optic vs. reflector + cover glass/ lexan..

  10. #10
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    Nice work

  11. #11
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    Quote Originally Posted by mattthemuppet View Post
    thanks for the info Troutie. I'm surprised that the lumen values are so close to the theoretical output of the bare LED (from the Cree datasheets), I would have expected a larger loss. Didn't you see that with your previous lumen readings from your 6 LED (XP-G?) light? I wonder if it's down to plain optic vs. reflector + cover glass/ lexan..

    To be honest Mattthemuppet I have not looked closly at the results just copied them on here
    been busy building a new bike and riding it with summer here lights are low priority at the moment


  12. #12
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    no worries.

    nice bike though, I'm guessing that it's your latest XC race machine?

  13. #13
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    Quote Originally Posted by mattthemuppet View Post
    no worries.

    nice bike though, I'm guessing that it's your latest XC race machine?

    Race and me in the same sentence
    my race career lasted 2 races about 20 years ago I am more a diesel engine than petrol

  14. #14
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    I'd bet you'd cream them all on the DH sections though!

    Looks like it would do pretty well over here - lots of very big rock gardens and long DHs. I had to up the travel on my fork from 100>130mm and add 3/4in of spacers under my stem just to cope.

  15. #15
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    must be a new record !
    3.2V * 2A = 6.4W ~121 lumen per watt , including optics, +10%+
    would make it over 130 per watt at 6.4W

    mine only gets about 86 lm/w once warmed up , at 2A.

    lumens usually go down, when optics added, and the measuring sphere
    has a diffuser. the smaller ones only can measure up to a point,
    where big lumen monsters , usually get measured in a room setup.

    lumens here or there, you do have one of the brightest lights !!
    looking good.

    ---> addition
    for ballpark figures , use cree calculator
    pct.cree.com
    optics 85% , electrical 92%
    these are probably still optimistic.
    reduce by 5% each, will get you there.
    still not counting , front glass, and tolerances.
    for reflector use 94% .
    lots of drivers, are actually under 90% efficient.
    now this is for quantity , quality is another story.
    -> color, CRI, light spread , distribution, etc.
    cheers, Rob

    Quote Originally Posted by troutie-mtb View Post
    Some more data just in from the Lumen Lab

    single XML T6 and Laura optic driven at

    out the front lumens

    3 amps 905 lumens
    2.5 amps 840 lumens
    2 amps 780 lumens

    ---------------------------------------------------------
    Triple XML T6 - Cute SS optic driven at

    3 amps 2883 lumens
    2 amps 2290 lumens
    Last edited by rschultz101; 06-18-2011 at 03:35 PM.

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