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Thread: 27w Ebay bike light 12v-18v

  1. #1
    Flashaholic*
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    Default 27w Ebay bike light 12v-18v

    I have just received this eBay bike light. Its definitely lighter and a tad smaller than the 10w VisionX/Magnalight Solstice.
    I just don't see how this light will stay cool enough when pushing 27w. It does get hot pretty quickly. Will have to time it to see when the thermal sensor shuts it off.
    Its all aluminum except for the metal bracket. The rear heat sink unscrews. Will need to replace the steel bracket with a copper or aluminum L-bracket so that it'll conduct heat away from the light and onto whatever I bolt it to(maybe thats what the wanna-be engineers were thinking....bicycle frame=big heat sink).
    Was going to use it above the garage to light a parking spot. Not sure if it'll survive being on 12hrs every night. Light is also a little spotty for me. Settings are low, medium, high, strobe, and SOS.
    The LEDs have 3 dice each. So, each die gets 3watts for a total of 9w per LED and 27w total on high. They look like 20mm stars so upgrading to XP-G, MC-E, SST50, P7 LEDs looks easy enough. I just don't think the housing is big/heavy enough for anything over 10w.
    Once I get the time, I'll pull it apart for some current/voltage readings and to see how its all wired.
    Want to use it as a 'fixed light'. Not sure if it'll survive being cooked at 27w all the time.




  2. #2
    Unenlightened
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    Default Re: 27w Ebay bike light 12v-18v

    Does it put out much light? How many lumens would you say it puts out?

    Thanks,
    Ambrose

  3. #3

    Default Re: 27w Ebay bike light 12v-18v

    Looks like 16 fins x 2 = 32 and the body. With some crude guesses from the picture I get about 100 square centimeters or about 16 sq inches. Or about 0.6 sq inches per watt. It better be very efficient. That's about 14% less area than a Magicshine per watt, and we know how they need their airflow. So you were right, a nice aluminum mount to an aluminum bar would be nice secondary heat sink.

    IMHO even with an excellent thermal path, you'd probably only want the full power for screaming descents. In a sedentary application you'll need a fan or more heat dissipation area or both. I wonder if some of the larger hobby motor heatsinks (helicopters etc) come in a 55 mm size? Some thermal epoxy to help thermal path, and you'd have more heat transfer area.

  4. #4
    Flashaholic*
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    Default Re: 27w Ebay bike light 12v-18v

    Using a small 3.2Ah 12v(measured 12.85v fully charged) battery swiped from my ups (be325r):

    Battery amp/voltage measurements:

    Low = .11A x 12.65v = 1.4 watts
    Med = 1.06A x 12.35v = 13.1 watts
    High = 2.04A x 12.05v = 24.7 watts

    Seller claims it to be 1500lm on high at 27watts. But, I'm at 91.5% power output(24.7/27)and will guess that 91.5% of 1500 is 1372lm. It is bright but won't know until I can compare the beam to something. And, there's gotta be some power lost to the driver........so chisel off another 100lm or so...... getting less efficient the more I type..... I have a feeling that the driver wants more than 12.8v.
    I will compare it later to my Quark Mini123(189lm) and the VisionX Solstice(900lm) when I get a chance.

    The steel metal mount doesn't conduct heat as it is barely warm when the frame surround is hot enough to burn. So, I'm definitely going to use a piece of copper or aluminum and make my own L-bracket. Also, I will probably glue a dozen or so copper 'ram sinks' leftover from my computer building projects. Hopefully the added mass & fin surface area add cooling reliability

    For $60, not a bad light. And, when the driver/LEDs burn out, I'll stick a trio of XPG's or P7's @1400 mAh for some real light.

    I will post dis-assembly pic's and hopefully a couple beam-shot comparisons tomorrow.

    The 3 LED's are wired in series and are about 10V on high. Each LED is at about ~3.3 volts.
    Last edited by deadrx7conv; 06-22-2010 at 08:47 PM. Reason: Added vf data

  5. #5

    Default Re: 27w Ebay bike light 12v-18v

    i vbought the 1500Lm version of this, its super bright! it's more like 1200 lm, but for 75 bucks who's complaining!

  6. #6

    Default Re: 27w Ebay bike light 12v-18v

    look for ebay seller id: '24x7diy' they have heaps

  7. #7
    Flashaholic* znomit's Avatar
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    Default Re: 27w Ebay bike light 12v-18v

    Whats inside that thing? I see three dies shoved together.

  8. #8
    Flashaholic*
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    Default Re: 27w Ebay bike light 12v-18v

    Unknown on the brand/type of LED.
    There are 3 dies in each LED, and without the optics, its a kaleidoscope of 9 dies kicking in.

    Since there is at least 8watt per LED, 1500lm rating is possible since its only 500lm per each LED. Even if the "OTF" is only 1200lm, how can you complain for the price? I'm guessing that my $120 VisionX Soltice which is rated to 900lm might only have 600-700lm OTF.

    Ebayer 24x7_DIY has the 550-660lm 9w(3LED@3w each) with normal Cree Q5's. Also seems to have a better 'mount' on the pricey 660lm version as the housing is tapped for a screw that I do not have. And, his 'Magicshine' clones have either MC-E instead of the P7. Interesting options.

    To find the light I received, search ebay for "12v 27w LED" as my light only costs $57.50 delivered!

    Bike mount is way better than the stamped steel 'insulator' that I have:


    Arrow shows screw, which I don't have, that locks the bike mount in place:

  9. #9

    Default Re: 27w Ebay bike light 12v-18v

    Hello
    Please check this picture to see the Visually Effective Lumen difference between Chinese 900Lm Bike Light and Indian 660Lm Bike light

  10. #10

    Default Re: 27w Ebay bike light 12v-18v

    Can you write the price?

  11. #11

    Default Re: 27w Ebay bike light 12v-18v

    I would really love to see some more pictures (in detail) of that housing!!

    What does the rear view look like without the heatsink?

    Any details on the inner parts of that housing?

  12. #12

    Default Re: 27w Ebay bike light 12v-18v

    heres some photos of the internals:

    the thickness at the edge is 1.5 and the thickness at the base where the heatsink touches is 3mm. the plate that the stars mount on is 6mm thick and makes contact with the outside housing.

    the optic can be replaced with this http://www.dealextreme.com/details.dx/sku.1915 or anything the same diameter i guess... pretty bright light!








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