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  1. #1
    Hack Racer
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    Brightness difference 1000mA and 750mA Cree LEDs?

    I can't tell the difference between running the Triple Cree XR-E Q4 LEDs at 750 mA and 1000mA. Does anyone have any side by side beam comparisons?

  2. #2
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    I have a tripple Cree Q4 light but I don't know how to double expose a digital camera to show the comparison. Actually, your not going to see enough of a difference to make a difference. You should be able to see just as welll with either.

  3. #3
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    Since you can't tell, you might as well run them at 1000mA, then get the bonus of added runtime.

  4. #4
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    You meant 700mA for added run time right?

  5. #5
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    Right, that's what I mean. Sorry for the confusion. It WAS early here...

  6. #6
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    I was noticing the same thing. Also, I'm finding that 400mA seems to be sufficient lighting for my needs at this point. I'm running a Fatman driver, with a resistor wired in for a high/low setup. The 1000mA is blinding, and the 400mA is still extremely bright.

  7. #7
    Singletrack Daydreamer
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    I certainly notice the difference between 1000ma and 400ma, but 400ma is plenty of light for climbing and medium speed riding. I'm using 134ma (using a 470 ohm resistor on the control pin on a 1000ma buckpuck) as my low beam at it seems fine with all three running and uses only about 1.5 watts. I don't know what the lumen output is at that level, but I'd compare it to a 10w halogen.
    Train 'til you puke. Cheat to win. Party like a rockstar. We miss you, Jan!

  8. #8
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    Quote Originally Posted by rockymtnway
    I certainly notice the difference between 1000ma and 400ma, but 400ma is plenty of light for climbing and medium speed riding.
    That's what I meant. Its plenty for the riding I do. However, there seemed to be very little noticeable difference from ~750 to ~1000mA when I was setting things up. I'm thinking of replacing the Fatman with a maxFlex to have the adjustable levels, and will try to post comparison beam shots if I do...

  9. #9
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    With a Fatman you can also make adjustable levels, it is quite easy. (search for big fatman topic).

    Off course you will see a difference between 750 and 1000 mA when you compare them side by side. But when you didn't ride for 2 weeks and I would give you your light, can you tell me then on which level it is?

  10. #10
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    Since the light output isn't exactly linear towards the top end, I'd expect less noticeable changes as you move up in current. The relation between the two is pretty linear to begin with, but does not stay that way.

  11. #11
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    Quote Originally Posted by super-fast
    With a Fatman you can also make adjustable levels, it is quite easy. (search for big fatman topic).

    Off course you will see a difference between 750 and 1000 mA when you compare them side by side. But when you didn't ride for 2 weeks and I would give you your light, can you tell me then on which level it is?
    What I meant was having the programmed settings for 350, 500, 750, and 1000 available at the push of a button. I've read the big fatman topic extensively. The real reason for making the switch is the low voltage shutoff option. I'm also getting a bFlex for another build so I can run my waterbottle battery on a different light.

  12. #12
    maker of trail
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    Yeah with LED's you reach a point of little gain with increased current.

    Keep in mind 750mA to 1A is not even twice, and even if it was a linear relation ship, we see light in a logarithmic scale, so double the power doesn't mean "twice as bright".

  13. #13
    Singletrack Daydreamer
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    It all comes back to when I bought my first Trailtech HIDs. I couldn't imagine anything brighter, then I rode with a guy with an L&M and noticed his were brighter. It really didn't matter from the perspective of being able to ride singletrack at speed, but side by side, you notice the difference. I'm starting to think about using 700ma dimmable pucks instead of 1000ma pucks in my future projects just for the battery life issue alone, no less the heating issues and LED life issues.
    Train 'til you puke. Cheat to win. Party like a rockstar. We miss you, Jan!

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