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  1. #1
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    another newbie without a light

    G'day to you all,

    I have some bits to build a small light (1st ever attempt) which I brought from a local electronics shop.

    There is a 1 x 10 degree lens
    1 x Cree XR-E LED
    1 x PSU LED Driver - Input = 3.0 Vdc; Output = 350mA (It's a AA-0590)
    3 x Batteries are 1.2V rechargeable (Ni-mH 2400 mAh)

    I have been unable to find info on - runtime; light output (lumens); watts, etc. The salesman said 185 lumens - is he correct?
    How does one work this out ??

    What else is needed for switching in 3-4 modes - off, low, med, high. I am mounting this in 25mm dia aluminium tube.

    I've looked at many posts and am a bit confused.
    Thanks

  2. #2
    aka RossC
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    It is very difficult to give an estimate of lumen output without knowing which XRE LED it is.

    Cree divide their LED's into "bins" which simply means that they grade each batch depending on what the final specs show from the samples they test. An R2 will be brighter and more efficient than a Q4 for example.

    Cree use a letter at the start of the name to show the model of let.

    "p" older than "q" older than "r"

    They then use a number to indicate the relative brightness

    e.g q1 dimmer than q2 .... dimmer than q5

    Without knowing much about the driver, 3xAA will be a greater input voltage than your 3.0v stated.

    EDIT: Oh, and I am guessing that the "brightness" quoted by the salesperson was probably for that particular LED when driven at 1000mA. At 350mA, it will be no-where near 180lumens

    Keep asking questions, people here are very helpful

  3. #3
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    Quote Originally Posted by ireland57
    G'day to you all,

    I have some bits to build a small light (1st ever attempt) which I brought from a local electronics shop.

    There is a 1 x 10 degree lens
    1 x Cree XR-E LED
    1 x PSU LED Driver - Input = 3.0 Vdc; Output = 350mA (It's a AA-0590)
    3 x Batteries are 1.2V rechargeable (Ni-mH 2400 mAh)

    I have been unable to find info on - runtime; light output (lumens); watts, etc. The salesman said 185 lumens - is he correct?
    How does one work this out ??

    What else is needed for switching in 3-4 modes - off, low, med, high. I am mounting this in 25mm dia aluminium tube.

    I've looked at many posts and am a bit confused.
    Thanks
    Thats a 350mA driver so you'll wont get much more than 100lm from one led, and the leds at Jaycar aren't top notch so likely less than that.
    You can't dim it either.
    Heres the datasheet:
    http://www.jaycar.co.nz/products_uploaded/AA0590.pdf
    You can't use three NiMH to drive one LED, you'll damage it.

    But you can drive two LEDs with it, and 4 NiMH.

    I had a look at efficiency and it was ok, sorry can't find the numbers right now.
    You'll probably find two NiMH will run for around 3hrs.

    Don't buy LED stuff from Jaycar, go to http://www.cutter.com.au/ for the good stuff, or http://www.dealextreme.com/ for cheap and ok.

  4. #4
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    The LED is a Q4; I had a choice of 750 mA but it was bulky.

    Bottom line is I know sfa about this stuff but would like to build some decent lights - helmet and bar mounted for 3 people.

    Thanks for the replies - the more I looked the more confused I got/am.

  5. #5
    aka RossC
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    Quote Originally Posted by ireland57
    The LED is a Q4; I had a choice of 750 mA but it was bulky.

    Bottom line is I know sfa about this stuff but would like to build some decent lights - helmet and bar mounted for 3 people.

    Thanks for the replies - the more I looked the more confused I got/am.
    This is a good place to start looking :

    http://bikeled.org/

    It was where i finally started to make heads or tails of what everyone was talking about.

    My advice:
    1. Figure out how much light you are shooting for. e.g 600 lumens (anyone who has spent some time looking at commercial products will have a bit of a feel for what a lumen is already)

    2. Then figure out how many LED's it will take to produce that light, (e.g 3x cree r2 @ 1000mA will give close enough to 600lumens)

    That then tells you what driver and battery combination you need.

    3. Then you need to figure out what the housing will look like and then you are all done. (Remember - LED's produce heat. Heat kills LED's. You need to make the housing out of something that conducts heat very well such as aluminium. The heat sink that the LED sits on needs to be thermally attached to the outside casing to help disperse the heat. You can't have too much cooling, but you can have too little.)

    4. If you are not committed to any particular battery size yet, then i think 18650 protected cells from deal extreme are the way to go. Much easier to manage than the 3 + AA's it takes to give the same voltage. Buy a battery holder from one of the producers on here and all is sweet.

    The stuff on deal extreme is cheap but I haven't had any probs with their batteries or chargers. It has free shipping, but it is sloooowwww - I just order and forget, then one day I get a nice surprise in the post

  6. #6
    aka RossC
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    Quote Originally Posted by ireland57
    The LED is a Q4; I had a choice of 750 mA but it was bulky.

    Bottom line is I know sfa about this stuff but would like to build some decent lights - helmet and bar mounted for 3 people.

    Thanks for the replies - the more I looked the more confused I got/am.
    Oh, and here are some relatively easy to build "classic" designs that might give some ideas about how to build these things.

    http://forums.mtbr.com/showthread.php?t=407160

    http://forums.mtbr.com/showthread.php?t=368896

    http://forums.mtbr.com/showthread.ph...ight=achesalot

  7. #7
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    Smile

    Many Thanks for your help.

    Looking at other lights I think 600 - 800 for a start; it's a lot better than what I got now.

    Cheers

  8. #8
    aka RossC
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    Quote Originally Posted by ireland57
    Many Thanks for your help.

    Looking at other lights I think 600 - 800 for a start; it's a lot better than what I got now.

    Cheers
    In which case 3x r2's in an achesalot or easy DIY housing would give just what you are looking for.

    I am assuming that you only have a single q4 at the moment? Perhaps make a DIY dinotte or something. That would fill in some time while you order some parts on DX which will get you started.

    r2's
    batteries
    charger
    battery holders ---> #1, #2, #3
    Driver Where the hell have all the drivers on DX gone??
    spot optics
    anyone know the sku for the faux Deans plugs? I can't seem to find them again.

    That would leave you needing some thermal adhesive (i like to use Arctic alumina adhesive) and a mom switch which you can get from jaycar. Probably something else that I haven't thought of yet.

    Good luck and take plenty of photos so we can see what you end up with

  9. #9
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    OK. Good info there.

    I'll see what I can do. I'll muck about with this stuff I got first and see if I can learn ....anything. lol

  10. #10
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    The poet can see beyond , over the fog
    The comedian describes the fog
    www.2you.it/ilmecca

  11. #11
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    I have finished a light fwiw.
    How do I load photos on here without exceeding allowed space?

    After another discussion with the salesman he assured me with this driver I can safely use 3 x 1.2 volt AA's on the 3.0 XR-E LED without a problem..... so I did.

    The end result so far..... it works.... hoorayyy!
    It only cost about 6 million dollars.
    It runs for 4.25 hrs (on new rechargeable AA's) with good light then fades quickly; dead at 4.5 hrs runtime.

    Apart from the cost (about $100) and problems with my workmanship it'll do as a starter... and means I can ride Monday night downhill (on bitumen) without killing myself.... or I can go even faster and need more lights.

    I am very keen to have another shot shortly.

    Any hints on photos most welcome.
    Last edited by ireland57; 09-16-2009 at 03:04 AM.

  12. #12
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    Forgot to ask..... some equation info if anyone can help?

    How do I find out:-
    If I require "x" no of lumens.....
    what wattage should it be run at?
    How many Volts would one use?
    How do lumens relate to volts or watts?
    How do I calculate battery run times (before buying parts) ?

    Thanks

  13. #13
    aka RossC
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    Quote Originally Posted by ireland57

    Any hints on photos most welcome.
    Two options. You can hotlink the photos from another photo hosting site such as flickr/ photobucket/ or your mtbr photo gallery using this button :
    1.jpg


    otherwise, you can upload them directly into the thread (but if people get an email notification of a reply, they can't see the pictures as links in the post) using this button.
    2.jpg

    The pics need to be smaller than 1024x1024 from memory

  14. #14
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    I don't know if these will work or not; they do on my computer.

    Please let me know if not working.










  15. #15
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    It's a direct copy (in looks only); the mount is a bit rough and there's plenty of work to do before the next ones.

    The good thing is even with the parts I brought it outshines any bike light I have at present.

    How do you calculate what size batteries are needed, what size driver to use?

    I used a boat canopy clamp to hold the light at present.


  16. #16
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    Can the Moderators please remove my previous "empty" posts.









    The beam shots are poor.
    The light is 1 x Q5 Cree Led + 1 x R2 driven at 350mA boost driver, 3.6 volts. In reality it is quite a good light for minimal power.
    Last edited by ireland57; 10-30-2009 at 06:57 AM.

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