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Thread: LED vs Xenon

  1. #1
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    LED vs Xenon

    I'm a Swedish enduro rider who has spend some time reading about your LED projects, I'm impressed!
    My question is what are the benefits of using LED instead of a xenon light?
    It seems like you mtb people prefer LED instead of xenon, even if it consumes the same power. I think we have the same requirements on a helmet light, and many of us enduro riders have batteries in a backpack for our light.

    Now I use a helmet light with a 35W xenon bulb, with the ballast it consumes about 42W, (12V, ~3.5A).

    I have just started a project with the new XM-L led from Cree and my hope is that I will get a smaller, lighter, cheaper and more robust system that generates more lumens than my 35W xenon light (3000 lumen).

    I will use 4 XM-L @ 2800mA, the optics is not decided yet, I want the beam to be quite wide so if someone know of a lens/reflector that I can use please post a answer.
    That leads me to my next question, lens or reflector? What's the difference?

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    Look at the beamshots, there are plenty of them in "XML discuss" topic.
    I would recommend Regina (reflector) or Iris (lens).
    XM-L lets discuss

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    For me and the enjoyment of making my own lights, it was always hard to find affordable xenon lamps and ballasts when MR11 and MR16 halogen lamps wer so cheap and out performed leds or that era by a long shot. Yes you had a big battery but you also had planty of light

    Now however the reverse has happened. Leds are incredibly bright, extremely reliable and rugged, plus, we have a huge choice of optics, colour temperatures, drivers etc that the Xenon lamps just don't cut it in my books anymore for mtb riding.

    The only downside of ultra bright leds, small form factor housings and the high running currents is thermal management. We all know that the cooler the leds run, the more lumen's they put out so a poorly designed housing can really drop the output from the theoretical. Plus, you do run the risk of cooking the leds if they get too hot.

    I am currently making some led lights for my brothers racing quad bike. The options are dual 7up XPG on the bars and a single 3up XML on the helmet, or a 16 up light bar on the handlebars and a 3up XML on the helmet. Either way it's going to be bright and not affected by vibration so reliability will be great, as long as the housings are waterproof. I will run off the alternator so external battery power will not be needed.

    As for XML optics, the lens's seem to be better at present. Have at look at the "XML lets discuss" threat for beamshots on what has been tested. Pick of the lens 's is the Ledil Laura and the reflectors, the Regina. You could also try a MR11 Ledil cute Quad optic for XRE and the Ledil CRS optics.

    Have Fun.
    Last edited by brad72; 02-13-2011 at 04:15 PM.

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    It's hard to beat an automotive type of HID light even with the latest LED's. You get all that light with just a single element. Focusing is also a bit easier than with LEDs. Now if you are riding singletrack you don't want too narrow of a beam, but where I'm at in the deserts of the American southwest a tight focus can be more important. The one thing that worries me about the HID is that you have a powerful high voltage source right next to your head. Things could go very wrong in a crash.

    You can certainly make a more robust system with LEDs. Cheaper? I doubt it. Lighter, maybe, maybe not.

    Instead of making a single light, consider two lights each with two XM-L LED's. Having only a single light invites sudden darkness in case of a failure.

    With the XM-L the efficiency of LED's is better than the 35 watt HID lights. I figure on about 2800 real world lumens out of a 4500k automotive HID. For the T6 XML a real world number is closer to 850 after heating effects are taken in to account. With decent drivers you should be able to run four of the XM-L's at full power which will give a bit more light than the HID you now use.

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    Another significant plus for LEDs is they are easily dimmed.

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    Quote Originally Posted by hoobs
    I'm a Swedish enduro rider who has spend some time reading about your LED projects, I'm impressed!
    My question is what are the benefits of using LED instead of a xenon light?
    It seems like you mtb people prefer LED instead of xenon, even if it consumes the same power. I think we have the same requirements on a helmet light, and many of us enduro riders have batteries in a backpack for our light.

    Now I use a helmet light with a 35W xenon bulb, with the ballast it consumes about 42W, (12V, ~3.5A).

    I have just started a project with the new XM-L led from Cree and my hope is that I will get a smaller, lighter, cheaper and more robust system that generates more lumens than my 35W xenon light (3000 lumen).

    I will use 4 XM-L @ 2800mA, the optics is not decided yet, I want the beam to be quite wide so if someone know of a lens/reflector that I can use please post a answer.
    That leads me to my next question, lens or reflector? What's the difference?
    Edit

    NVM, I just realized you wanted a helmet light and not one for your fairing.
    Last edited by kan3; 02-13-2011 at 09:19 PM.

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    Quote Originally Posted by vroom9
    You can certainly make a more robust system with LEDs. Cheaper? I doubt it. Lighter, maybe, maybe not..
    You make a very good point about the cost and weight. A reliable system needs a quality driver etc and good thermal management means more material for heatsinking.

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    What about the LM1 RS 21 deg. lens for MC-E?

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    Xenon and LED bulb technologies provide an improvement over but leds are more durable and reliable and last longer than xenon. the life expectancy is 100,000 hrs of operation.

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    Great thoughts from many here. One thing you are all missing is penetration.
    Talking about Lumens doesnt really do the job here.
    A good 30 + Watt HID in a spot form will more than double the distance of any LED that I have seen(small enough for a helmet mounted light and a usable beam.. semi spot 12deg)

    It sounds like the system the OP is using a remote Ballast HID.. Osram or sim.
    Thats scarry to me..
    There are 30 watt HID Helmet mounted lights that have a integral Ballast..Guess who makes those Much safer.
    LEDs are coming of age and eventually will out preform the HIDs. But Not yet.. LEDs are Great for the MTN Bikers.. but still a bit behind in overall preformace for the Moto guys..
    Small lights anyways...Here is the Big Daddy
    .

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    Quote Originally Posted by off road rider
    Great thoughts from many here. One thing you are all missing is penetration.
    Talking about Lumens doesnt really do the job here.
    A good 30 + Watt HID in a spot form will more than double the distance of any LED that I have seen(small enough for a helmet mounted light and a usable beam.. semi spot 12deg)
    ]
    What LED do you have direct experience with? My 6up xpg running at 27w is quite a bit better than the 35w x2 HID.

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    Quote Originally Posted by kan3
    What LED do you have direct experience with? My 6up xpg running at 27w is quite a bit better than the 35w x2 HID.
    Just a few
    www.cyclopsadventuresports.com
    Remember, I am talking helmet mounted lights here..
    The LED light on the bike shown will blow away a 8" HID race light
    Making a blanket statement about LED vs Hid is not quite comparing apples to apples
    I personally have won 24hr Moto races using No bike mounted light, Only a helmet mount HID.. I would never even attempt that with any LED helmet mount setup currently available.
    Speeds over 50 MPH negates any LED helmet mounted light.IMO

  13. #13
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    Good luck with that.

    Hope you don't crash, or anything.

    kthxbye

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    Quote Originally Posted by off road rider
    Oh, so just commercial products? Which for the most part are outdated.

    Remember, I am talking helmet mounted lights here..
    Missed that actually, sorry

    The LED light on the bike shown will blow away a 8" HID race light
    I sure hope so. They're claiming 80+ watts which if used with an xm-l would be ~5900 lumens out the front or about 7800 gross lumens

    Making a blanket statement about LED vs Hid is not quite comparing apples to apples
    I agree

    I would never even attempt that with any LED helmet mount setup currently available.
    What was the best helmet light you've seen and what driver, led and optic did it consist of? That feels like a blanket statement in its own right unless your well versed in most lights from commercial to small time diy style.

    Speeds over 50 MPH negates any LED helmet mounted light.IMO
    Same response as above


    Assuming you had the mill or lathe, you could build a LED helmet light for about $200 that would beat 99% of all commercially available HID helmet lights. You're coming into a DIY forum where most users products here best commercially available units and commenting how those commercial products aren't as good as HID.

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    Dont get your undies in a bunch Kan3 .
    . I applaud you DIY guys, Its how I got my start.in the business..
    Fact is Lumen ratings really dont mean squat.. You can belly ache all you want about LEDs. But put your scratch papper and calculator down. They are Great and are the future. But for a small package, a well Reflected high powered HID will work better on a Dirt Bike.(That was the OPs use for said light). Simply due to the penetration of a well reflected, high powered HID and the lack of it on led side..
    I do have some Incredible LEDs we have built here in the shop.. Things you may see in the next year or so. I like them very much.. But If I'm riding fast and racing.MOTO. guess whats on my lid...Thats My very experienced Opinion. I value yours.. You Might have more experiance at 70+ MPH than I do??

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    I've said it before and I'll say it again. Higher powered as in 25 to 35 or more watts, HID has the advantage due to a more concentrated source. That smaller high intensity source is a lot easier to focus. However, not everyone needs 2000+ lumens in a 6 degree beam. I will say that I have wished for one when I had to keep my night time desert riding closer to 55 than 70 because I was out riding my available lighting. Now I prefer tight mountain singletrack at night (or the day) and a 6 degree spot beam is not the optimal in that condition. Speeds are low and a wide spread of light is better since you rarely can see more than 100 feet.

    On my nighttime bicycling outings I really can't say that a 6 degree spot HID is what I would want. Each situation requires different tools. Every day the LED is becoming the better tool. Certainly in the case of the small 11 to 13 watt HID's the LEDs have passed them in functionality.

    Even though LEDs keep getting better I'm not sure they will pass the high power HID's any time soon.

    It's all about the proper tool for the job and for most of the members here that is a LED light. It is a bicycling forum after all.

    One thing I can tell you for sure. There are a lot more people who ride at night on bicycles than on dirt bikes. I have a hard time finding people to go with and I live in Southern California. I have made a few converts though. It's just so cool to ride at night.

    The main issue that I see at this time in making a HID level light is the size and weight of a LED solution. That and how do you cool the thing.

    For overwhelming lumens there was that guy that build a light with a 100 watt LED array that he overdrove to insane lighting.

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    Quote Originally Posted by kan3
    Assuming you had the mill or lathe, you could build a LED helmet light for about $200 that would beat 99% of all commercially available HID helmet lights. You're coming into a DIY forum where most users products here best commercially available units and commenting how those commercial products aren't as good as HID.
    It's not actually that easy. A unit for comparision would be the Trailtech MR16 size HID unit. It's about 1800 lumens if I remember correctly, but on teh spot beam unit it has a 6 degree beam. I'm pretty sure that is a total width so in LED optic speak that would be a +-3 degree optic. Now that is the same as a XP-G and an Iris. It would take four of those to be the same as that Trailtech light. It comes in a larger heavier package.

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    Penetration? I'm not quite sure if I understand you (I'm Swedish ).
    Do you mean that (in theory) a xenon with the same lumen output and with the same beam angle as a LED light has better ability to penetrate air?
    And you mean the result of this is that the xenon light beam travels longer in air, better "light at distance"?

    I have now build a helmet light with 9 XM-L's that I have compared to my 35W xenon helmet light.
    At the same power consumption ~42W the xenon light is beaten pretty much both in light output and "light at distance".
    The xenon light have a 70mm Mila reflector and the LED have 9 LM1 RS 21 deg. lens for MC-E, I think the beam angle is about 25-30 deg. with the XM-L.
    In the test the LED light LED's had a average forward current of ~1400mA (digitally PWM dimmed).

    Have you any theory of why the xenon has better penetration ability than a LED light?
    I develop wall penetrating radar and in that case the penetration ability depends on the frequency of the transmitted radar signal and the dielectric constant of the material you want to penetrate.

    In the xenon/LED case the material is air and visible light has a frequency range of about 405 THz to 790 THz.
    I can't see that the penetration ability can be worse in a LED light, but if you know why please tell me.

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    Quote Originally Posted by off road rider
    Dont get your undies in a bunch Kan3 .
    . I applaud you DIY guys, Its how I got my start.in the business..
    Fact is Lumen ratings really dont mean squat.. You can belly ache all you want about LEDs. But put your scratch papper and calculator down. They are Great and are the future. But for a small package, a well Reflected high powered HID will work better on a Dirt Bike.(That was the OPs use for said light). Simply due to the penetration of a well reflected, high powered HID and the lack of it on led side..
    I do have some Incredible LEDs we have built here in the shop.. Things you may see in the next year or so. I like them very much.. But If I'm riding fast and racing.MOTO. guess whats on my lid...Thats My very experienced Opinion. I value yours.. You Might have more experiance at 70+ MPH than I do??
    I might not, but these guys sure do...


    That's the Audi R18 LMP1 proto by the way, currently in final testing. It utilizes full LED headlights, not just the DRLs you see on above. If you want the ultimate answer to weight, efficiency, and power... That's it. Every gram counts on those cars, higher efficiency means less alternator load (which means more power for the wheels) and for endurance racing you need flamethrowers on the front.

    Penetration is a function of optics. for light sources, LEDs are the newly crowned king. The optics may not have caught up quite yet, but they're not far behind. And certainly replacement LEDs are a hell of a lot cheaper than quality replacement HID bulbs!

    Then again, you may have more experience at 200+mph than they do.

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    Quote Originally Posted by vroom9
    It's not actually that easy. A unit for comparision would be the Trailtech MR16 size HID unit. It's about 1800 lumens if I remember correctly, but on teh spot beam unit it has a 6 degree beam. I'm pretty sure that is a total width so in LED optic speak that would be a +-3 degree optic. Now that is the same as a XP-G and an Iris. It would take four of those to be the same as that Trailtech light. It comes in a larger heavier package.
    Having used both systems (Trail Tech 30w HID and a Troutie 7up) the 7Up is good, very good, but the HID has a depth that I miss and want to replace but LED is not quite there yet - for me, the move was the cost of replacement HID bulbs, this p'd me off.

    On the HID, the width from the spot was actually quite wide but the depth was just amazing, now if I could get that from LED's I would be happy, the other thing (and size matters here) is the 7UP (because of heat) will not run at full output for very long whereas the HID will run at full volume for the duration of the battery's runtime and that also makes a huge difference.

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    Quote Originally Posted by off road rider
    Dont get your undies in a bunch Kan3 .
    I'm not upset that you gave your opinion. If I came off that way it wasn't intended.

    Thats My very experienced Opinion. I value yours.. You Might have more experiance at 70+ MPH than I do??
    My experience is road racing, supermoto and enduros. Supermoto doesn't count as there aren't night events. At 80-100mph, I've found 6up xpg r5 and reginas better than a 35w hid. I tried and disliked the TT mr16 6deg bar mounted beam for enduros. I also hate that the blub "seems" to have a ridiculous low life span. My enduro bike is battery powered so my ability to build the beam width to my liking and reduce power consumption allows me much longer run times with similar results. Maybe his terrain is different then what we have in my area but you never get to desert racing speeds.

    Also, if you're doing 24hr endurance races by yourself, how many battery packs do you have to carry?


    Quote Originally Posted by hoobs
    Do you mean that (in theory) a xenon with the same lumen output and with the same beam angle as a LED light has better ability to penetrate air?
    And you mean the result of this is that the xenon light beam travels longer in air, better "light at distance"?
    No, they mean that it's hard to get the same beam width in LED at high powered applications than it is for HID.



    Quote Originally Posted by efmax
    Having used both systems (Trail Tech 30w HID and a Troutie 7up) the 7Up is good, very good, but the HID has a depth that I miss and want to replace but LED is not quite there yet - for me, the move was the cost of replacement HID bulbs, this p'd me off.
    The troutie 7up uses carclo lens though.
    Last edited by kan3; 03-30-2011 at 06:36 PM.

  22. #22
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    given the picture (Golddigger's I think) of an SST-50 with an aspheric lens looking like some kind of futuristic orbital defense lazer, I don't think it's about LED vs. HID but new and untested optics/reflectors vs. established technology.

    I also think that the ability to put multiple LEDs in the same thermal package as a HID allows a lot more freedom in tailoring the beam pattern to the situation. Also note that with LEDs, the larger the reflector, the better the throw. A lot of the builds on here are small, due to weight constraints, but the 35mm+ reflectors almost always produce better throw.

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    Quote Originally Posted by kan3

    The troutie 7up uses carclo lens though.

    Correction it used the Khatod optic

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    Quote Originally Posted by troutie-mtb
    Correction it used the Khatod optic
    Am I confusing that with the Liberator or does that product not use them either?

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    LED lights are small, and you can group them together to concentrate light. LED lights are good in areas that need bright, direct lighting, such as displaying art or under kitchen cabinets to highlight counter space. You can use LED lights in high-traffic areas because of their durability. You also can use them in waterproof devices, according to toolbase while LED lights are small, and you can group them together to concentrate light. LED lights are good in areas that need bright, direct lighting, such as displaying art or under kitchen cabinets to highlight counter space. You can use LED lights in high-traffic areas because of their durability. You also can use them in waterproof devices, according to toolbase.

    source: livestrong.com
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