Focusable LED setup?

[gearfreak]

Trying to sort out the optics for a headlamp build/mod that I am planning for a adventure racing lamp (biking, running,kayaking etc..)- either a Lux V or 2 K2's.

The main problem is that I feel that a single beam angle would be a compromise for the different activities- eq want a spot/throw for picking checkpoints, and a wider angle for riding.

Any suggestions on the best way to do this? or should I just resort to 3 K2's and put out enough light that it doesn't matter where I point it?

 

[hotbeam]

Just use a 10deg optic on one LED and a wide angled on the other. You can try Fraen or a couple of other manufacturers. So were you going to wait till '06 before doing this.. since this is when the K2 is likely to be available.

 

[HarryN]

I have played with the Lux III, Lux V, a very good K2 prototype, and the Cree 1 and 3 watt parts. My suggestion, if you can make it work, is to use a pair of Lux Vs, one setup for distance, one for flood. Alternatively, use a Lux III for the spot on activities.

The reason, is that while you may not be entirely thrilled with the challenges of focusing it, you can drive the Lux V at 3 watts and get quite a bit more light from it than a Lux III driven at 3 watts. (efficiency follows to some extent LED die area) Driving a Lux V at 3 watts is a good way to reduce the heat load as well.

The K2 is a very nice package and a very nice, bright LED. Just like the Lux III, the die will be brighter at 3 watts than the Lux V (so in some ways, better for throw), but it is not a replacement for the Lux V in terms of total light output at 5 watts, IMHO.

The Cree part is a nice 3 watt design as well. The optics I have on hand did not take full advantage of the very different light angle output (more from the front like a Lux V), which requires a deep reflector to make effective. I did not see a clear advantage to using the Cree part, but it is competitive. There are some threads in the LED section on this part and its electrical comparisons to the Lux III.

Availablility of the K2 remains very limited and AFAIK, only limited engineering samples are being released to customers for product development support. It might be useful to make your light able to "upgrade" from a Lux III to a K2 in the future.

From a comfort aspect, the heat might feel good in a kayack, but a full 5 watts on your forehead is pretty warm.

 

[snowman]

I have been debating what to do for my adventure racing light as well. It is the most challenging application for a single light I can think of due to the wide variety of situations it must be able to accommodate; Activities ranging from high speed technical biking to up close map reading. Some typical goals of such a light would be:

*Light weight and compact size.
*Long run time with multiple/adjustable brightness levels.
*Durable and waterproof.
*Useful and flexible beam shape.
*Easy to use.

Some things to consider to achieve these goals are:

*Highly efficient battery(s), light source(s), and reflector(s) to reduce size/weight and increase runtime.
*Excellent thermal properties to increase efficiency, (assuming LED) minding size and weight.
*Both a remote battery hookup and an on board battery for differing situations.
-Say AA batteries on board and a battery pack for more demanding applications.
*Hand held, helmet/head mount and handlebar mount capability.

I figure over the winter I will try and get a prototype(s) made. I'm always looking for ideas on designs and solutions and recently I have reconsidered the ability to achieve it all with one light. I may work on building a lighting package that will suit the needs and work well in an adventure racing setting.

 

[gearfreak]

Thanks for the feedback, my original plan had been to use a single Luxeon V, mounted into a yukon or myo (with heat sinking of course) until i started to find out more about the beam pattern of the luxeons and how they would focus.

How much variation in beam pattern can I expect achieve with a single star mounted into a smallish reflector like the yukon or myo?

Snowman- I've played with a 3W setup (Min Min lights) here in Australia and its nearly perfect apart from the fast decents. So by my calculations a single 5W, a 11.1v 2.4Ah lithium ion(150g), and a nFlex driver, could get me through a night stage of riding (50-100% output) and treking (25% output).