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  1. #1
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    Cheap buck drivers for red LEDs?

    First, yes I'm aware of fellow Kiwi torchboy's driver list, which has been very helpful in my research :-)

    I'm looking for cheap drivers for red power LEDs for 3x or perhaps 4xNiMH and 1xli-ion. Something under US$5 or US$15 for 3 including shipping for one. A slow flashing/blinking mode would be good too although not essential (edit: since I may add blinking myself if necessary). I live in NZ so anything in the US, UK etc, even probably Australia is likely to be expensive when shipped so realisticly I'm looking at DX/KD/eBay etc.

    The only things I've really came across are the AMC7135 linear regulator boards (likely crappy efficiency given the low Vf), AX2002 boards (sadly don't have modes, at least not cheaply and not blinky/flashy) or the LEDA 0712 boards (have modes but likely less efficient then AX2002 and limited info exists on these, I haven't even seen a datasheet).

    One of the issues here is while there's ample headroom between the Vf and input voltage, many of the chips aren't rated to go that low, for example from the AX2002 datasheet, 3.6V input is the minimum input and I still have no idea what happens below that when there's ample headroom from the Vf. Also from what I gather, most 5 mode boards tend to have a rather fast strobe.

    There a bunch of shot in the dark stuff like KD product ID 9908, 9910 and 9912, but I haven't been able to find out anything about them and I'm not particularly interested in being a guinea pig :-P and they and exactly cheap and don't claim to have modes even.

    Are there any other drivers people would suggest I'm missing? Or any other thoughts, suggestions etc? As you may have guessed, things like the microbuck or bflex etc are a bit too expensive for my needs.

    I did make a post at CPF http://www.candlepowerforums.com/vb/...d.php?t=285379 which has some more details.

    Cheers
    Last edited by Nil Einne; 08-14-2010 at 12:01 AM.

  2. #2
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    I don't really know if this will help you or not but when I messed about with the idea of running a few red Cree power LEDs a while back I just took apart a few old cheap rear blinky lights and used the drivers from those. They have the right modes as they were rear lights to start with and you'll find old rear lights laying around unwanted if you look/ask hard enough.

  3. #3
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    You can get 200mA out of a 555 timer. Thats brighter than any blinky out there.
    DIY LED Bike Lights:
    A few Dynamo builds and some Small battery lights

  4. #4
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    Yeah I forgot to mention

    Yeah I forgot to mention one of the reasons I wasn't so concerned about blinking was because I thought I could add blinking myself somehow (well I'm not really asking for help with that at the moment, I have various ideas)

  5. #5
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    Quote Originally Posted by yetibetty
    I don't really know if this will help you or not but when I messed about with the idea of running a few red Cree power LEDs a while back I just took apart a few old cheap rear blinky lights and used the drivers from those. They have the right modes as they were rear lights to start with and you'll find old rear lights laying around unwanted if you look/ask hard enough.
    Thanks for the suggestion. Did you just run them without modification (other then substituting the LED)? I did wonder about something like this but it seemed the current would be fairly low.

  6. #6
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    I don't think they do have modes and the ones with modes are either hi/med/low and the useless strobe and sos. You'd be better off with a single mode driver and building the blink yourself with a 555 and a transistor to switch them?

  7. #7
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    Nil Einne, no mods, the current is not very high but you'll still get tons of light when you swap from the 5mm LEDs to the Cree power LEDs. I never actually measured the current but with a driver nicked from the light in the attached pic I was able to run 2 Crees in parallel and get them warm and very bright from a single 18650.

    Donor driver came from one of these:
    Attached Thumbnails Attached Thumbnails Cheap buck drivers for red LEDs?-donor.jpg  

    Last edited by yetibetty; 08-14-2010 at 05:23 PM.

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