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  1. #1
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    Winner of triple Cree P4 LED vs Overvolted Halogen test

    Work has been a bear and I'm traveling until Friday, but hopefully, I'll get the beam shots done this weekend (if the wife doesn't mind). I finally got the Cree completed and it turned out quite nice. HOWEVER, to save the suspense, the halogen beat the Achesalot-design triple Cree by a wide margin. This is with the Ledil square optics. The IMS-20 reflectors performed much better and I'll try to get those pics as well, but, I estimate the Halogen is putting out in the 1500 lumen range, whereas the Cree is in the 600 range (at 1 amp).
    Based on cost, taking battery out of the equation (using same spec battery pack on both), the halogen wins again ($8 vs about $80).
    The Cree definitely wins where run-time is concerned. I get just under 2 hours on the halogen and over 4 on the Cree.
    I bought enough parts to build two+ LED's, so if anyone is interested, I have an extra nFlex, 5 P4 LEDs on stars and lots of Ledil optics (I didn't know which would work best, so I bought a bunch of each RS, SS, etc.). PM me if interested.
    Okay, gotta get back to work.

  2. #2
    fuggansonofahowa
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    How about a drop test.....

  3. #3
    Gone riding
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    It’s an interesting test and it definitely shows that there is still merit in playing with overvolted Halogens in terms of dollars / lumens, but it seems like a bit of a strange comparison.

    With the numbers you have given I’m assuming you’re running a 20 watt Halogen, substantially overvolted to get those lumen numbers. Roughly, you’re probably looking at close to three times the power consumption of your triple Cree based light?

  4. #4
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    Yes!

    Yes, 20w 12v, overvolted about 25% (depending if battery topped-off or not). Bulb life on halogen is between 50 and 80 hours (been using for a while, one bulb lasted about 56 hours, the other in the 70's based on log). I scooped up a bunch of GE bulbs at $0.99 each, so replacement isn't an issue and cost is very acceptable. I keep a spare on rides since they can be replaced so easily.
    Can't beat the halogen for the budget rider who only needs about an hour of max light.
    I DO like the option of changing optics/reflectors on the LEDs to change beam pattern. With the halogen, you're stuck with narrow or flood (I prefer the narrow).

  5. #5
    Gone riding
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    Your bulb life sounds a lot better then I was expecting for some reason, itís definitely a very effective way of getting a lot of light for little cost.

    With a 25% overvolt, do you notice much of a shift in colour temperature at all?

    I was also wondering if you have ever thought about using a PWM dimmer for your Halogen system, or would you just rather run it at maximum brightness all the time?

    Dave.

  6. #6
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    I use a 14.8 volt battery with 12 volt 20 watt halogen lights: around 20% - 30% overvolt. I have only really compared it to (I think) a HID Industries - small Australian company - 10 watt HID and mine was just as bright (although slightly more yellow). My son competed in the local 24 hour race last year and when looking at various other lights mine didn't seem at a disadvantage to any of them (again, not as white as the HIDs or the LEDs).

    When i first fired the light up the bulb blew after about 4 hours, but it was at least 5 years old. I have since clocked up around 100 hours on the second bulb. With a 4000 mAh battery I get about 100 minutes run time.

    I run this light with a low end Dinotte on my helmet. I'm not sure it is even a 3 watt emiter. I find that its spot is "brighter" for my purposes than a 5 watt Dinotte that I also have. I will try replacing its emitter with a Seoul this weekend. I have noticed though that the current emitter has a hole in the centre of the back of the star, while the back of the Seoul's star is solid. I will carefully drill it out and see what happens.

    I am very tempted to try a god light as describe by Homebrew elsewhere and will see if I can find some 6 volt 5 watt halogens this weekend. The only drawback is I think I'll have to settle for an MR11 instead of my current MR16 globe and I'll have to then change the ceramic connector as I understand the pins are closer together. If I can get 20 hours out of the globe I will be happy. But I am not sure it will safe riding it on the street if I blind people.

    Perhaps a PWM with the god light would be the way to go.

    Tim
    Last edited by Wombat; 08-24-2007 at 07:45 PM.

  7. #7
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    Quote Originally Posted by Uphiller1
    Work has been a bear and I'm traveling until Friday, but hopefully, I'll get the beam shots done this weekend (if the wife doesn't mind). I finally got the Cree completed and it turned out quite nice. HOWEVER, to save the suspense, the halogen beat the Achesalot-design triple Cree by a wide margin. This is with the Ledil square optics. The IMS-20 reflectors performed much better and I'll try to get those pics as well, but, I estimate the Halogen is putting out in the 1500 lumen range, whereas the Cree is in the 600 range (at 1 amp).
    Based on cost, taking battery out of the equation (using same spec battery pack on both), the halogen wins again ($8 vs about $80).
    The Cree definitely wins where run-time is concerned. I get just under 2 hours on the halogen and over 4 on the Cree.
    I bought enough parts to build two+ LED's, so if anyone is interested, I have an extra nFlex, 5 P4 LEDs on stars and lots of Ledil optics (I didn't know which would work best, so I bought a bunch of each RS, SS, etc.). PM me if interested.
    Okay, gotta get back to work.
    Interesting comparison you have done! There is definately some merit to a very low cost system for the occasional night rider, and a system like your overvolted halogon would fit nicely for some short rides every once in a while. Although I seriously doubt your 1500 lumen estimate! You mention in a later post that it is about as bright as a 10 watt HID, which is about 500 lumens. Maybe your LED optics are not positioned correctly in relation to the LED itself? A triple Cree running at 1 amp should be just as bright, if not brighter than a 10W HID.

    And as far as doing any kind of 24 hour events with your halogen, I simply would not trust it, not to mention the need for lots of heavy batteries. My 14.8V 2600 mAh battery will drive my triple Cree light for over 5 hours at 700mA, not to mention the opton of dimming the light while climbing for even longer run times.

    Mark

  8. #8
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    bikeny,
    I think you might be mixing my thread and Wombats. I haven't made any comparison to a HID, nor would I use the light in a 24 hr. race unless I had an ample supply of batteries (and a back-up on hand). The 1500 lumens estimate is on the low-side as it should be in the 1650 range based on GE's charts.

    Low_Rider,
    There is a noticeable color shift. The halogen is a LOT whiter when overvolted. I'm not saying it isn't still yellow compared to the LED, but not as yellow as at 12v.

    Again, I will attempt to get good beam shots tonight or tomorrow and get them posted.

  9. #9
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    I have a Turbocat s47 and have compared it to an L&M Arc. Never compared it to any upper end LED's though that would be interesting. For comparison sake, the s47 on high drowns out the HID except for the bright spot in the center. The s47 is 10% overvolted w/ a NiCad battery and the light is quite a bit whiter than other halogens in our group. I have no idea of lumen output as it's not listed on TC's web site. I run this w/ another light as run time sucks (40 min) on high. However, quality is superior so I'm contemplating a better after market battery. Difficult choice as there are some awesome new LED's coming out.

    MB

  10. #10
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    Quote Originally Posted by Low_Rider
    It’s an interesting test and it definitely shows that there is still merit in playing with overvolted Halogens in terms of dollars / lumens, but it seems like a bit of a strange comparison.

    With the numbers you have given I’m assuming you’re running a 20 watt Halogen, substantially overvolted to get those lumen numbers. Roughly, you’re probably looking at close to three times the power consumption of your triple Cree based light?
    I have to second Low_Rider on that. Run both lights in a situation where each is drawing the same power, say 10 watts, from the battery and re-examine the results. We must look at lumens/watt in any fair lighting comparison. I generally don't like pulling more than 11 or 12 watts from my battery pack, so a 25 watt drain would not be acceptable. Is the halogen really the winner if they are not playing by the same rules? (power)

    Thanks for posting though and for taking the time to build a triple Cree. What bin Cree did you end up using? (Never mind, I just saw the mention of the P4 at the end of the post).

  11. #11
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    Quote Originally Posted by Uphiller1
    bikeny,
    I think you might be mixing my thread and Wombats. I haven't made any comparison to a HID, nor would I use the light in a 24 hr. race unless I had an ample supply of batteries (and a back-up on hand). The 1500 lumens estimate is on the low-side as it should be in the 1650 range based on GE's charts.

    Low_Rider,
    There is a noticeable color shift. The halogen is a LOT whiter when overvolted. I'm not saying it isn't still yellow compared to the LED, but not as yellow as at 12v.

    Again, I will attempt to get good beam shots tonight or tomorrow and get them posted.
    You are correct, I did mix up your posts, sorry about that. It does sound like your using similar systems though. Anyway, 1500 lumens is ALOT, way more than I would need! My triple Cree with about 550 lumens was plenty, with a single LED helmet light, for my first 24 hour solo race at Allumuchy this past weekend. It even survived the overnight torrential downpours while I was riding!

    Mark

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