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Thread: new 9 cree light i made

  1. #1
    Flashaholic aljsk8's Avatar
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    Default new 9 cree light i made

    just a look at a tripod flood light i made





    the purpose of this contraption is to light up areas in total darkness
    to allow skateboarding in the winter months (skateparks etc)

    the light will brightly light up a 5m radius and then sufficiently light up a 20m radius - which is enough for my needs

    it is made from a camera tripod
    aluminum sheet
    heatsink (cpu)
    9 x cree p4
    3 x 3w 1ohm resistors
    wire
    12v 12ah sla battery

    cree's are 3 parallel sets of 3 in series

    battery under load is 12.4v and after 1hour is 11.8v

    so id be interested in knowing the current to each cree (at the start and end of 1hour)

    the heatsink just gets warm - as its in the cold winter air

    let me know what you think of the light (and the answer)

    Alex

  2. #2
    Flashaholic* LED Zeppelin's Avatar
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    Default Re: new 9 cree light i made

    Cool. My nephew is also into skateboarding and recently purchased some halo worklight floods and a generator.

    If he sees yours he'll want me to build one for him.

  3. #3

    Default Re: new 9 cree light i made

    Out of interest which CPU type heatsink is that?
    Looks nice and big!

  4. #4
    Flashaholic aljsk8's Avatar
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    Default Re: new 9 cree light i made

    led zep - originally i had the idea of halo work lights and a generator
    but the cost and weight put me off - and all the messing with petrol etc

    so then i made this tripod but for a year it had 2 x 50w halogen globes
    obviously not as bright as the work lights but cost 1/4 of the price of a generator but the battery started dimming at 40mins runtime and was dead after 1hour - not good for skating or for the SLA battery

    so this winter i did the cree's - now it lasts twice as long and is just as bright

    and you can carry all this in a backpack

    just need to work on a bit of protection for the front

    -----------------

    not sure about the heatsink i just got them off an IT guy i know
    but i do have another one

    -------------------

    so can anyone help me figure out what im driving these cree's at??

    thanks

    Alex

  5. #5
    Flashaholic*
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    Default Re: new 9 cree light i made

    Awesome!!!

    I wouldn't have paralleled the LEDs though, as the one with lower Vf will suck more current and eventually burns before the others, and then the others would burn. I have a couple of cheap torches with parallel LED, they reliably and systematically burned.

    Please correct me if I'm wrong about parallel / unbalanced load / burning; as I am not certain about the theory behind resistors

    I prefer 3 buckpucks 1000mA for 3 Cree each; they're cheap, potted, and efficient. If you want to spend extra $ you can have the ones with external potentiometer; as you can overdrive them up to 1200mA.

    I made a fixed lighting with BuckPuck with ext. pot. and it scares my wife; she said that she couldn't accept the fact that a tin chocolate box can emit light; she feared explosion

  6. #6
    Flashaholic aljsk8's Avatar
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    Default Re: new 9 cree light i made

    i dont think any of them will burn out if that is what you mean

    the heatsink works very well and all the leds stay cool

    i use this thing perhaps 2 hour a week for 20 weeks of the year

    so the leds get used 40 hours per year - ill probably change the leds long before there is a problem with them

    Alex

  7. #7
    Flashaholic
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    Default Re: new 9 cree light i made

    Ive thought about doing that (the local police took issue with us parking out cars on the skatepark for night time bmxing). so its good to see it working might motivate me to do something (got other (mostly unrelated) projects to do first though).

    Ive not experimented much with high power LEDs yet but i think you you wont get the problems mentioned of parallel LEDs because you (correctly) havent used one resistor for parallel loads.

  8. #8
    Flashaholic aljsk8's Avatar
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    Default Re: new 9 cree light i made

    good to see there are other "extreme sports" people who are also flashaholics!

  9. #9
    Flashaholic curlyfry562's Avatar
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    Default Re: new 9 cree light i made

    Amazing build , I am definitely building one of these. I have decided to run 4 of the tri-LED Rebel stars, 2 in parallel for each 1000mA Buckpuck. Because of the 2v drop across the buckpucks each LED will be receiving 10v @ 500mA, which I figure is close enough to the recommended 9.45v. I am going to use a large heatsink, although not quiet as bis as yours, but I was wondering how you attached the heat sink to the tripod mount. I was thinking of using epoxy, but it doesn't look like there is a great deal of surface area on the tripod to work with.
    Specs:
    Input 12v 2A
    Output 1,300 lumens


    Thanks for the concept, once again great idea. I will be making an Instructable on it in about a month http://www.instructables.com/group/danpowerled/
    awesome website, this is a group devoted to LEDs

    I will link this thread in the instructable

  10. #10
    Flashaholic* TorchBoy's Avatar
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    Default Re: new 9 cree light i made

    Quote Originally Posted by aljsk8 View Post
    so id be interested in knowing the current to each cree (at the start and end of 1hour)
    ...
    let me know what you think of the light (and the answer)
    It's a pity no one ever answered that question. The light is great, but to give you an answer we also need to know what the operating voltage of each triple LED string is. Something around 10.5-11V probably.
    No, a torch does not always mean flames.
    Ian.
    LED Driver List - now database driven and with new search features.

  11. #11

    Default Re: new 9 cree light i made

    Dude, this is almost exactly what I've been planning! I got a couple aluminum blocks in earlier today (technically yesterday), and I drilled and tapped them for tripod mounting. I'll be using 11 Crees in series with a 1-ohm resistor and three 12V 10Ah SLAs (also used in my HMM) for the larger one, and four Crees driven by two KD "Kennan" drivers for the smaller one. I'll be finning the blocks and painting them black for emissivity.

  12. #12
    Flashaholic aljsk8's Avatar
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    Default Re: new 9 cree light i made - need advice on revamp - Phlatlight, Bridgelux, mce, p7

    well the dark nights are only a few months away and night time skateboarding will be upon me and my friends

    i want to revamp / refine the setup in post 1

    ill be using the same tripod and i have plenty of heatsinks cable and conectors so all i need is advice for leds and resistors or drivers

    the current setup is 9 x cree xre P4 leds at about 1.2A

    im guessing about 1800 Lumens and about 50 l/w

    heres my requirements:

    2500 Lumens or more
    50 l/w or more
    £40 or less ($65)
    no reflectors needed
    less emitters the better
    4000k would be nice but no more than 6000k

    can be newer crees, mce's, p7's, Phlat 50, 90, 360 etc Bridgelux....

    just need to know some options prices how to drive etc

    thanks

    Alex
    Lights - Not enough

  13. #13

    Default Re: new 9 cree light i made

    Neat light!

    if you mount a CPU fan onto the heatsink, you could supercool the LED's........and perhaps overdrive (is that the right term for more voltage?) or "superclock" them
    MY EDC: JETBEAM M1X - it replaced 8 other lights.

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