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Thread: Need advice for a CREE DRL project

  1. #1

    Default Need advice for a CREE DRL project

    I folks. I thought I'd come here and ask for some advice on a new project after reading some of the posts here to give me various ideas.
    Basically I'm building a fiber-optic Daytime Running Light (DRL) kit for a vehicle.

    I'm using CREE XML T6 modules (4 in total) and after reading some posts on this forum I've decided to use a Taskled driver.

    Just to backtrack a minute, I initially tried a hipCC driver and ran two of the T6 LEDs in series. The driver and the first LED unfortunately blew up within a second of applying power. Something must have shorted out on me, but I'm sure that the circuit design was fine. Anyway, I've got a replacement H6CC driver coming from Taskled but I'm keen not to repeat my costly little mistake, so before starting again with some fresh bits, I wanted to clear up some questions I had and I'm hoping people can give me some advice here.

    - OK.. input power is straight from the car (i.e. 12-14v avg.). Do I need to consider anything before hooking that straight into the H6CC?
    - I want to be able to run 4 T6 LEDs. Now if I run them all in series, my combined vf would probably be around 14-15v in which case that's probably no good in combination with the H6CC right? So the question I had is whether it's feasible to run the LEDs as 2x2 (twin series LEDs connected in parallel) from the one driver or is it better to get two drivers and just run 2 T6 modules in series (as per my original test) ?

    From everything I've read, I know that running the LEDs in parallel is bad voodoo due to the uneven current matching, but are there exceptions to this rule?
    Thanks for any advice or hints on a reliable driver design for on running a quad XML-T6 in a vehicle application.

  2. #2

    Default Re: Need advice for a CREE DRL project

    Welcome to the forum. Please keep in mind that vehicle lights are regulated as to their design, construction, performance, and durability throughout the world. Specific regulations vary by country, but the common factor is that lamps and reflective devices not certified or type-approved to the applicable regulations are not legal. Homemade lamps (as such) are not illegal, but whether you are making two lights for your own car or two million lights for an automaker's entire line of vehicles, your lamps must be tested and certified/approved to the applicable regs or they are not legal. While a range of performance is permitted for every function, the requirements are quite specific and they apply to mandatory as well as optional functions, so if you are in the USA, for example, the fact that DRLs are not mandatory doesn't change the fact that if they're present on a vehicle, they must comply with the regs. Please keep in mind that Rule 11 of this board prohibits advocating or discussing illegal activity.

  3. #3

    Default Re: Need advice for a CREE DRL project

    Quote Originally Posted by Scheinwerfermann View Post
    Welcome to the forum. Please keep in mind that vehicle lights are regulated as to their design, construction, performance, and durability throughout the world. Specific regulations vary by country, but the common factor is that lamps and reflective devices not certified or type-approved to the applicable regulations are not legal. Homemade lamps (as such) are not illegal, but whether you are making two lights for your own car or two million lights for an automaker's entire line of vehicles, your lamps must be tested and certified/approved to the applicable regs or they are not legal. While a range of performance is permitted for every function, the requirements are quite specific and they apply to mandatory as well as optional functions, so if you are in the USA, for example, the fact that DRLs are not mandatory doesn't change the fact that if they're present on a vehicle, they must comply with the regs. Please keep in mind that Rule 11 of this board prohibits advocating or discussing illegal activity.
    No worries. I'm not proposing to do anything illegal. Here in Australia it's perfectly legal to fit aftermarket DRL kits as long as they are switched. Most auto stores sell a vast variety of them here and they're a great idea because it's making the cars more visible. Unlike the US we don't yet have mandatory DRL regulations which include a swag of do's and dont's. I'm sure eventually we'll probably go the same way though.

    More importantly, I'm not even at that stage where I can toy around at mounting anything on a vehicle yet. I'm more interested in designing a light engine in combination with side lit fiber optics and one of those uses is for a DRL kit. The main problem I'm having is how to get enough light into the fiber to make them really visible in daylight. I'm getting promising results when butting the fiber right up against the dome of the T6 LEDs which are amazingly bright but that brings interesting challenges in terms of thermal management, which I'm yet fully to solve.

    First thing for me is to get the electronics right, as it's one of my weak points. The CAD and mechanical design aspects are less of a concern for me.

  4. #4

    Default Re: Need advice for a CREE DRL project

    Quote Originally Posted by DBO6 View Post
    No worries. I'm not proposing to do anything illegal. Here in Australia it's perfectly legal to fit aftermarket DRL kits as long as they are switched
    Yes, but they must be tested and certified compliant with applicable Australian regulations (ADR 76 and 13 ) or type-approved under applicable international regulations (ECE R87 and R48). Homemade lamps are neither unless you go to the expense of putting your lamp through the required testing. Lamps not ADR-certified or ECE-approved are not legal on public roadways. The design, performance, construction, and durability requirements contained in the regulations are quite specific and particular and cannot successfully be guessed at. You don't get to just declare "Hey, it's a DRL" because you think it looks nice and bright

    Most auto stores sell a vast variety of them here and they're a great idea because it's making the cars more visible.
    Yes -- DRLs are a good idea. Yes -- there are a lot of ADR/ECE-compliant aftermarket DRLs widely available. No -- this does not mean homemade DRLs are effective, safe, legal, or a wise idea.

    Unlike the US we don't yet have mandatory DRL regulations
    The US does not have mandatory DRLs. However, if DRLs are installed they must be certified as compliant with Federal Motor Vehicle Safety Standard 108, which contains specific, particular requirements for lamp design, construction, performance, and durability. That is the same situation that presently exists in Australia, except rather than FMVSS 108 Australia uses the regulations referenced above.

    By all means, keep experimenting and building, but take some time to become familiar with the regulations that apply to the lamps you wish to build, if you ever wish to use them legally on public roadways.

    designing a light engine in combination with side lit fiber optics and one of those uses is for a DRL kit.
    Osram showed such an item in their Joule lineup about a year ago -- interesting application.

  5. #5

    Default Re: Need advice for a CREE DRL project

    That's the trouble in Australia, the states are all different. In Queensland the relevant regulation which covers vehicle modification (and DRL fitment) is Division 4 (Section 67) of the Transport Operations (Road Use Management—Vehicle Standards and Safety) Regulation 2010. What you are referring to are the guidelines under the Commonwealth which are over-rulled by the state legislations.

    They are working on combining the acts to be more in-line with Commonwealth regulations to unify the country, but it's been years in progress and will probably take a while yet.

    Hey you got any extra info on that Osram item you mentioned? What prompted me to toy around with some of this stuff was actually seeing the new Audi A1 headlight DRLs, which use some kind of Optical fiber or ribbon of sorts. Looks very neat. Not quite as bright as some of the direct LED models, but still very noticeable.

  6. #6

    Default Re: Need advice for a CREE DRL project

    Quote Originally Posted by DBO6 View Post
    That's the trouble in Australia, the states are all different.
    Same in the United States and in Canada -- the States and Provinces each have their own vehicle lighting installation and usage codes, some of which explicitly require lamps to be compliant with the national standard and some of which do not, but in all three cases -- US, Canada, and Australia -- the national regulatory structure contains provisions against the importation and sale of noncompliant equipment.


    What you are referring to are the guidelines under the Commonwealth which are over-rulled by the state legislations.
    They're not "guidelines", they're regulations, compliance with which is not optional, and generally the national standard preempts the state standards through one of several different chains of regulatory coverage.

    I admire your initiative and creativity, but sidestepping through what looks to you like a gap in the law does not exempt this conversation from the prohibition on discussing illegal lighting modifications. If you persist, the thread will be closed.

    Hey you got any extra info on that Osram item you mentioned?
    It's their Joule JFL light source with an integral light guide that can of course be a range of curved or linear shapes. As far as I know it has not been commercialized because no automaker has yet bought it, but I could be wrong about that.

    Audi A1 headlight DRLs, which use some kind of Optical fiber or ribbon of sorts.
    There are a lot of DRLs like this coming onto the roads. Audis, BMWs, Fords, etc. Expect to see more of them.

  7. #7

    Default Re: Need advice for a CREE DRL project

    Quote Originally Posted by Scheinwerfermann View Post
    I admire your initiative and creativity, but sidestepping through what looks to you like a gap in the law does not exempt this conversation from the prohibition on discussing illegal lighting modifications. If you persist, the thread will be closed.
    Fair enough you're the moderator here so do what you feel is right and I'll accept that.
    It's always good to point out pitfalls for people starting works which could potential see them get into hot water with relevant legislation. I have no problem with that. However I just think that it's a wrong to make an immediate assumption of illegality without a) knowing the exact laws yourself and b) having no doubt that a breach is likely.

    Let's not forget, this is a prototype project that hasn't left the bench - not an illegal lighting modification. If I was posting photos of an illegal act, or asking for advice on how to fit a knowingly illegal item to a car then fair enough. Who's to say that if the design actually works as potential DRL that in the end I would not consult the relevant authorities to ensure that the device meets the guidelines before fitting to a road-going vehicle ?

    You know I was just looking for like-minded enthusiasts who could offer some of their experience and advice on designing a circuit. Hopefully I can still get some of that advice, either from yourself or others on this forum.

  8. #8

    Default Re: Need advice for a CREE DRL project

    By all means, yes, proceed as long as the conversation doesn't veer into on-road use of noncompliant lights. Just needed to put the matter in front of you. Please carry on.

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