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  1. VanIsleDSM

    Brightest MR16 LEDs?

    Nice job Eltehs. I build and sell/install MR16 conversions locally, though I haven't gotten into active cooling with the Nuventix coolers yet. I prefer passive and very efficient setups. Spending more on LEDs and reducing current across them to reduce heat and gain higher efficiency, though...
  2. VanIsleDSM

    Reflow Soldering MC-E

    We shouldn't be trying to heat and cool the LED so quickly. Thermal shock is what will kill the LED during reflow soldering, from being heated too quickly, that's why CREE recommends a maximum of 3C/s on warmup, and 6C/s on cool down. It should take a minimum of 2 minutes to get to the point...
  3. VanIsleDSM

    Lowest ESR ceramic caps for LED drivers?

    Thanks for the reply jtr, I've already found the lowest possible resistance inductor I can fit, while paying attention to magnetic losses in the core as well, along with the other points you have mentioned. ESR, while not playing a huge roll in efficiency, will still add to it if lower, just...
  4. VanIsleDSM

    Lowest ESR ceramic caps for LED drivers?

    Trying to maximize efficiency for an LED driver I'm building, and I'm looking for the lowest possible ESR (equivalent series resistance) ceramic capacitors. In the past I have used the panasonic ECJ series capacitors, which are "low ESR" caps, but they do not actually give a value. I have been...
  5. VanIsleDSM

    Lowest ESR ceramic caps for LED drivers?

    Trying to maximize efficiency for an LED driver I'm building, and I'm looking for the lowest possible ESR (equivalent series resistance) ceramic capacitors. In the past I have used the panasonic ECJ series capacitors, which are "low ESR" caps, but they do not actually give a value. I have been...
  6. VanIsleDSM

    RGB array, why blue so hot?

    Hey thanks jtr, I hadn't quite put that together, but it makes complete sense. Yes everything else is very cool, that's why I was wondering. Thought I was just getting some bad thermal conductivity. Well I suppose everything is gravy then :) I've got this thing fading through the whole...
  7. VanIsleDSM

    RGB array, why blue so hot?

    Using some luxeon rebels in an array, 3 red, 3 green, 3 blue. All SMT soldered onto triple mounting MCPCBs and screwed onto a large heatsink. Running 700mA through each colour in series. I've always thought that the green with only about a 5% efficiency or so, would get the hottest. And the...
  8. VanIsleDSM

    What's in a cop's light bar?

    That attitude disgusts me. The holier than thou take on things has lost the police around here a HUGE amount of respect lately. Along with all of the taser killings and abuse that have been happening there's about to be an uprising. You are in place to serve and protect us, you knew what you...
  9. VanIsleDSM

    Has anyone tested an MC-E to destruction?

    I built some of these boards that allow you to solder an MC-E directly to a piece of a copper, probably saves anywhere from 1-3C/W. I haven't gone overboard on the testing yet, but I'd like to see what I can get it up to.. I have an M flux WD lying around somewhere that was sent to me.. and I...
  10. VanIsleDSM

    IP65 LED array enclosures for outside?

    Headlamps no, taillights yes. Although I took part in a few discussions about them. The taillights are still incomplete unfortunately.. haha. Pretty much done, but I've still got to diagnose a fishy issue the controller board, can't seem to pull the voltage regulators low, there's a current...
  11. VanIsleDSM

    IP65 LED array enclosures for outside?

    I've been searching for a while now and haven't been able to come across any IP65 rated aluminum enclosures for LEDs. If anybody knows of any specifically for LEDs that'd be awesome. If not even just a slim profile IP65 aluminum case with a window on the front that I could attach heatsink(s)...
  12. VanIsleDSM

    SSC Acriche

    I've played with an acriche, I don't like them too much. I'd much rather have a proper LED with a constant current driver. The acriche has noticeable flicker in my peripheral vision as it pulses with the AC power, not very nice for the home. As for the whole mains power danger subject, I...
  13. VanIsleDSM

    rear lights for my car project

    I highly recommend getting genuine lumileds superflux LEDs for your tail lights. The red/orange and amber are DOT certified colours for use on the road, and they are very high quality. 70mA each, you'd want about 15 per side minimum. 150mA versions are also available if you want to use less...
  14. VanIsleDSM

    Best method for attaching LED to star?

    You stick it right into the paste. If I'm soldering an IC I touch the board and paste first, and then move up the pin of the device and pull away.. all done quite quickly, about 1 second, as the small SMT pins don't take much to heat up. I wouldn't use a soldering iron for an SMT LED though.
  15. VanIsleDSM

    Best method for attaching LED to star?

    That board was done by hand with the LodeStar solder paste from DX. Place the solder paste first, and then put the components down, then use a soldering iron. Hold the part down with a toothpick for the first joint, and then it's solid for any other soldering.
  16. VanIsleDSM

    How do you protect your eyesight when playing with LEDs?

    A #5 is most likely far more than you would ever need. The robotic welding machines I work with produce a welding arc 44X the intensity of the sun at high noon on the equator. A #10 or #11 is all that's used. #12 is for extremely hot welding.
  17. VanIsleDSM

    Best method for attaching LED to star?

    I imagine you could mix it with another type of flux, as long as it didn't react badly with whatever flux is left over in your dried paste. As for stirring a syringe I'm not sure. None that I've ever bought has come in a syringe, Usually something like a pill bottle or film canister. Keeping...
  18. VanIsleDSM

    Best method for attaching LED to star?

    Well could be, but all the soldering paste I've used has been.. well, paste-like. Sometimes some near the top dries out and I would describe it as moist sand. Once you mix it back down into the flux it's all good again.
  19. VanIsleDSM

    Best method for attaching LED to star?

    If your solder paste is like moist sand then it's either dried out and no good, or you need to stir it up. The real key to remember when SMT soldering is that temperature alone is not what is going to kill your LEDs. The most likely failure will be from thermal shock. Heating the star until...
  20. VanIsleDSM

    Cree MC-E (4S) at 1000mA too high?

    I made some special mounting boards for the MC-E seen here: http://www.candlepowerforums.com/vb/showthread.php?t=206088 I'm away at work right now but when I get home I'll make a few for some CPFers to try out. These should help eek out as much heat as possible to safely run at 1000mA with...

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