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  1. #1
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    CREE XM-L 1600 & 3800 lumen flashlights on eBay

    I tried searching the forum for users or reviews on the CREE XM-L 1600 and 3800 lumen flashlights being sold on eBay, but couldn't find any. From the looks of all the listings, a lot of these flashlights are being sold everyday. I am curious if these flashlights are good for handlebar or helmet mount alternatives to Magicshine's MJ-808E, which is rated at only 1000 lumen from the same XM-L led using 4 18650 Li-ion batteries. The 1600 lumen flashlight uses only 2 18650 batteries, so how can it output 600 more lumens with the same XM-L led using fewer batteries?

    The 3800 lumen flashlight has 3 XM-L LEDs mounted in a triangular pattern to the head. Some versions allow 2 18650 batteries, while others allow 3 18650s. The price is half of what the MagicShine MJ-808E is, so I'm quite interested to know what riders think about these flashlights, if you all have first hand experience to share. I like the idea of having 3 XM-L LEDs instead of just having 1 XM-L led on the MS MJ-808E for 1/2 the cost. I'm leaning more towards the 3 18650 batteries version of the 3x XM-L 3800 lumen flashlight, unless I hear informative arguments that I would be better off buying the MS MJ808E.

    Comments, input, answers, or suggestions, would be greatly appreciated.

  2. #2
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    Not really...

    Straight from the CREE XM-L Datasheet:
    The highest lumen count bin on the XM-L is the T6 (Cool white) rated at 280 lumens at 700mA. (Same bin as what is advertised on the 1600 lumen flashlight).

    The maximum drive current for the XM-L is 3 amps... Drive it harder than that, and 1) life expectancy falls off and 2), efficiency falls off. There is a 325% increase in the 700mA level lumen output when driving at 3 amps.

    So...
    280 x 3.25 = 910 lumens

    Now add on about 5% derating for the heat losses (50 degC) and you're down to 865 lumens. Not to mention any reflector losses.

    Even if they were able to drive the emitter at the full 3 amps, the boost converter would be burning some wattage as well. Run times on high (assuming a 3 amp drive) would be well under an hour.

    The reality is that most lumen counts from flashlight makers like this are inflated. In this case, it's just blatant false advertising. Not saying it's not a bright flashlight, but 1600 lumens? No way.

    Oh, and by the way, if you want to see what an honest 3800-ish lumens and 5200 lumens looks like on the road from the rider's perspective, you should check out my YouTube video:

    DesignShine DS-1300 Night Time Lens Comparisons - YouTube

    There does come a point where you are putting too much light down on the road/path.
    Last edited by pethelman; 08-20-2011 at 08:32 PM.

  3. #3
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    Reputation: colleen c's Avatar
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    I'm guessing you are refering to something like or similar to Trustfire TR-3 3800 lumens 3 x XML flashlight. It is listed to have a runtime of 1.5 hrs. If it was really 3800 lumens, I would have bought one myself.

    I have a Dry 3 x XML T6 1A CW flaslight. It uses 3 18650 battery in series. The LED is direct driven at 3amps. Even at that it is rated at only 2500 lumens and I honestly think that is a realistic true rating for this torch (at the LED not OTF) A real 2500 lumen flashlight will run hot and the battery will run only an hour. To complicate things further, you will need good quality battery such as Redilast, or AW. The flashlight will easily draw over 2.5 amp from each cell meaning that most lower grade cell will not handle that. Even if it does, the IR will build from the heat where the light will dim fairly fast. So count on spending an extra $50 to $60 for battery.

    Another issue is the size. Anything larger than a single 18650 flashlight will have a big footprint. You will want to look into modding it smaller running external battery as I did for my Dry flashlight before considering helmet mount.

  4. #4
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    A handheld flashlight can probably be presumed to have a lower duty cycle in operation that a bike head light that might be expected to run for 3 hours or so. pethelman nails it - and I'd expect the reliability of these flashlights to be pretty lousy when operated as a bike light. They'd be ok to turn on and shine around for a few minutes but running them for extended periods is going to likely cause them to fail prematurely.

    J.

  5. #5
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    Quote Originally Posted by ussprinceton2004 View Post
    ... The 1600 lumen flashlight uses only 2 18650 batteries, so how can it output 600 more lumens with the same XM-L led using fewer batteries?
    ....Comments, input, answers, or suggestions, would be greatly appreciated.
    1600 lumen from a XM-L emitter?.......UHH...I think NOT. I don't know how the rules on E-smay work but stuff like this shouldn't be allowed. Very sad. Kudos to the OP for asking the question and bringing this sham to light.

  6. #6
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    Wink

    Pethelman has placed these 1600 Lumens lights in context. Vastly over rated lumens. I add the following. Lumens is not a direct measurement of brightness. Brightness is measured either in Candela (metric candle power) or in Lux at 1 metre. Brightness measure gives the final result that includes the lens and/or reflector performance. If you need to learn more try this link: not yet allowed, it can be supplied

    I have tested a low cost 1600 Lumens light (A$19.50) see this link: Can be supplied
    Fully zoomed in, the brightness is 15,000 candela, not bad but indicating a LED output in the region of 300-500 Lumens, this will mean a longer battery life (reduced current draw). It runs with one only 18650 battery, a spare and a charger for two batteries are supplied. Plus a holder for three AAA batteries as an alternative.

    In essence all focused light/lamps should be specified in Candela. One candela = one lux at 1 metre.

    It would seem a good move for the Chinese to stop misleading with fancifull specs and creating a bad record by changing to Candela specs that represent big and impressive numbers that are real.
    Last edited by davmax; 01-24-2013 at 07:47 PM.

  7. #7
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    Now tested the lamp in my last post for current drain. It is 1.5 amps from the one 3.7 volt 3200mAh battery. Therefore a battery life of greater than 2 hours and according to the data sheet an output of 467 lumens, allowing for losses. Within the estimated lumen output in last post.

    In summary a bright lamp (up to 15,000 candela) with over 2 hrs battery life and low cost.

  8. #8
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    Well I fell for it (1600 model). I guess it will be good for a secondary light when it arrives.

    If the price is too good to believe, well then . . .
    Thanks to www.weavercycleworks.com for my awesome bike frames!

  9. #9
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    Quote Originally Posted by Manicmtbr View Post
    Well I fell for it (1600 model). I guess it will be good for a secondary light when it arrives.

    If the price is too good to believe, well then . . .
    The cree 1600 gives plenty of light to ride with! Completely surprised and satisfied for the price. Easily mathches my older twin niterider that I paid 4or 5x the price ... in 1994!!!!!

    It will be interesting to see if I have to modify the batt box for the 1600. Kinda flimsy- but probably an easy mod.

    Can't wait to get the triple led version.

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