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  1. #1
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    Idea! Electra Bullet Headlight Hot Rodded With Cree R2

    Here is my Electra Townie Balloon 3 (more info on it and it's carp slaying usage in this thread: http://www.bikeforums.net//showthread.php?t=444390)

    The Electra LED Bullet Headlight: http://www.electrabike.com/miva/merc...egory_Code=CLT is a sweet looking retro light, but the stock LED has the candle power of, well, one candle. It's unsafe and useless as a light but it looks really cool.

    Enter Cree, problem solved! I used a "Cree R2-WC 250-Lumen 5-Mode Memory Drop-in LED Module for Flashlights (3.6V~8.4V)" SKU 14442 from DealExtreme: http://www.dealextreme.com/details.dx/sku.14442), some of these battery holders: http://www.batteryspace.com/index.as...OD&ProdID=2320 and this set of 3.6v RCR123A batteries and charger: http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1387

    The Electra switch is easy to use as a momentary switch to select modes with no modification. You just flip it back and forth to cycle modes, then click it all the way on once you find your desired setting.

    To mount it I sanded the (plastic) reflector plate down until the drop-in fit perfectly through the hole. Three daisy chained tie wraps hold it in place to center and aim it. Silicone II is liberally goobered around the tie wraps and module to hold it firmly to the reflector.

    I used the drop-in's aluminum reflector module in this setup to provide more of a heat sink. The brass heat sink of the circuit/LED is too hot to use on it's own mounted to the plastic reflector. As an added bonus, upgrades will be as easy as unscrewing and desoldering the old one and popping a new one in.

    The battery holder assembly is made and mounted with 3M Scotch Dual Lock (über velcro), a velcro retention strap, super glue and a bit of extra double sided tape to fit the curve of the light chassis.

    With 2ea. 3.6v RCR123A batteries in series at 7.2v (8.4v peak) it runs on "high" for 2 hours of nice bright light, then about a half hour of OK light equivalent to medium on a full charge. I have another battery holder built for the option of adding two more cells (in series parallel, still 7.2v) for longer runtimes. I avoided putting it in right away because the LED's heat sink (the brass ring you see) gets very hot and would be very close to the batteries. I would rarely go for a ride longer than 2 hours at night, but if so it's fast and easy to change batteries, even by feel in the dark.

    I didn't add a protection circuit to this but I may do so if I decide to add a charging jack. Protected cells would work nicely as well, I considered these: http://www.batteryjunction.com/uf16340.html and may upgrade to them in the future.

    There you go! A light can look retro cool and still be functional. I'm VERY pleased with the performance of just one Cree R2, the hotspot and ring are clearly visible on the road even directly under streetlights. It lights up the local canal path very well. On my first test ride I stunned and blinded an opossum - it didn't move until I was about 2 feet away from it, then I saw it's eyes reflecting moonlight in the bushes as I passed. Electra LED Bullet Headlight - Now with 'possum stunning action!

    I hope those looking for a retro yet functional bicycle light find this post illuminating.

    PR
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    Last edited by paulrichardson; 09-19-2008 at 05:28 PM.

  2. #2
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    Here's some beamshots from my evening ride.

    This is a the same phone camera that I used for the other shots, it doesn't perform as well in the dark so work with me here. I like the hot spot and fill this has, it lights up the path in front of you as well as things on the sides. Not bad at all for a single emitter with no optics other than the reflector. I also like how the hood gives it the "Eye of Sauron" shape. I'm not at all bothered by the shadow of my Fat Frank tire, it's like having a peepsight to aim the LED death ray with.
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  3. #3
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    Wish I would have thought of that. I put a mini mag head with a cree in it on the front fender of an old torquer cruiser a while back. It looks ok but converting a real retro lamp would be better. I bet your now thinking the same thing i am, I want a generator hub.

  4. #4
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    Looks nice and retro! my only concern would be the heat build up inside the head...

  5. #5
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    Quote Originally Posted by bikerjay
    Wish I would have thought of that. I put a mini mag head with a cree in it on the front fender of an old torquer cruiser a while back. It looks ok but converting a real retro lamp would be better. I bet your now thinking the same thing i am, I want a generator hub.
    Hmm, a generator hub would be interesting, but it would have to include a front brake - my Townie has Shimano Nexus hub brakes on the front and back. If I installed one I'd probably have the fork drilled to hide any ugly wires, though. A generator hub would be a nice companion for a Rohloff 14 speed internal hub in back... when I win the lottery

  6. #6
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    Quote Originally Posted by SkUG
    Looks nice and retro! my only concern would be the heat build up inside the head...
    Thanks!

    I've had no heat issues yet, there seems to be enough airspace in there to cool things off. I have the wires bent to stay away from the heat sink when it is closed, but I will retain them somehow when I'm done playing with the circuit. While testing it indoors at home with no airflow the lense and chassis feel slightly warm but not alarmingly so. The batteries never feel warm at high charge or low. I'm not ever completely discharging the cells, I shut it off before the beam gets really weak.
    Last edited by paulrichardson; 09-19-2008 at 08:19 PM.

  7. #7
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    Cool "sleeper" light, and simple design!

  8. #8
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    Here's a white wall beamshot, light on "high". My phone camera struggles to capture medium and low, but you get the idea.
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  9. #9
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    I stunned a bunny with this light tonight! He froze when I hit him with the ray and didn't move for a good 2 minutes or so. Again, crappy pictures at night from my phone cam, but that is indeed a rabbit stunned by a Cree R2! This product WAS tested on animals! My bicycle is a menace to wildlife.
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  10. #10
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    Just a note on this light after some use - It is BRIGHT. It's unbelievable how bright just one R2 is! I've had cars flash their brights at me and pedestrians have told me I was blinding them. Animal and human testing have been successful! I bet the multi-LED arrays some of you DIY leave people with charred and smoking eyesockets.

  11. #11
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    Awesome Idea!

    Great work Paul! I've been using your posts to get an idea for upgrading an vintage bullet light for a newly acquired Raleigh Sports. Just wondering if you could give some advice.

    Is there a big difference running the LED module using rechargeable AA batteries instead of CR123's? I think there will be room inside the housing of this light for a four unit AA pack. I'd like to have the option of a longer than two hour run time at full brightness and maybe even running it at medium during the day for extra visibility. Great idea for the protected cell BTW!

  12. #12
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    Quote Originally Posted by arkiemark
    Great work Paul! I've been using your posts to get an idea for upgrading an vintage bullet light for a newly acquired Raleigh Sports. Just wondering if you could give some advice.

    Is there a big difference running the LED module using rechargeable AA batteries instead of CR123's? I think there will be room inside the housing of this light for a four unit AA pack. I'd like to have the option of a longer than two hour run time at full brightness and maybe even running it at medium during the day for extra visibility. Great idea for the protected cell BTW!

    Thanks! No idea on the power issue, I went right for the rcr123a's, I'm sure if you use enough AA's to get the voltage up and you have the space to put them in, they would work just fine - I used rcr123a's for their size, I'm cramming all that in there but leaving some "air" for heat dissipation. I bet some of the power engineer types on this site might be able to offer you better advice, sorry. I'm actually not going to worry about protected cells until these die, they are still working fine for me. I'm not going to put a charging jack on it, I don't mind pulling them out to charge them. I still might put the other two cells inside, heat does not seem to be much of an issue at all.

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