Help / Tips for home-made headlamp

Hi there folks,

I'm new to this board, but have been reading most of the last few weeks of postings and have used search to look further back.

What I'm primarily interested in is LEDs. My current project is to update my head lamp I use when running in the evening (when it's dark, especially in the winter here in Germany) or while competing in night-orienteering events (Any orienteers around here? I didn't want to buy an expensive Silva or Mila, so I built my own...)

At the moment, I use a lamp I built using a front light reflector from a bicycle, modified to take a 6W and 10W halogen bulb. I can choose between these two bulbs with a switch. They are powered by two 7.2V/1700mAh rechargeable battery packs from my RC car. The two batteries can also be switched. They are carried in a "harness" made of an old foam sleeping-mat (you know, for camping), cut to a sort of bra worn backwards.

The reason why I switch between the two batteries is to reduce the risk of something vital breaking (for instance, a branch ripping the cable off one of the packs when I crawling through the undergrowth near an orienteering control) and leaving me standing in the dark. I use two different bulbs also to reduce failure, but also to have a normal light and a brighter light for when I need to shine down a path when I'm lost Currently, each battery lasts about 60 minutes on 6W or about 45' on 10W. That makes a maximum safe time of 2 hours competition time.

I'm looking into upgrading to LEDs mainly for one reason: I'd like to increase shine-time while keeping the brightness of at least the 6W bulb. Of course I don't want to spend toooo much.

And now (after that rather long intro) to you all:
* Are LEDs an option at all? Or should I look into better batteries?
* What sort of LEDs would you recommend - I was thinking of 2 or 3 1W-Luxeons - but haven't yet got a clue about how they compare to a 6W-halogen.
* Of course I need voltage regulation - any ideas how best to reduce 7.2V down to 3V for the LS?
* Wich lens should I take - lamb. or batwing? Or maybe even mix them? One far-beam and two floods?
* What battery savings (= what run times) could I expect?

Any help on the above plus any other useful comments are welcome.

CU, Simon

I suggest looking for a Rayovac Sportsman multi-LED headlamp, it has a 3 position switch for 1)single white LED 2)2 RED LED's 3)xenon spot.

I removed the xenon bi-pin lamps and istalled a direct drive LS on a circular aluminum heatsink, others here I think have also done this mod its pretty easy, the original headlamp uses 3 AAA batteries and generally sells for $10-13 USD.

For a really good headlamp mod I would get a Stadium Catseye HID bicycle lamp and install several cyan 5mm LEDS OR...a lambertian cyan LS on another switch and circuit for the voltage needed. This is just a mental planning map and not an actual project I have done. The size and weight of the Catseye I hear is very compact and light. Mounting on something comfortable to wear while jogging is another issue, but the HID will give you immense light even if used for defensive purposes. The color cyan is IMHO a better choice than a near white.

Back to your original project it sounds like a good candidate for the 5 watt Luxeon for a hi-output lamp and a regular LS for low light OR...3-5 single 5mm LEDS, dropping resisors work well on current below 200ma, the 5w LS though I have no experiance with but a regular Luxeon 1 watt puts out sufficient light at 188-250ma current consumption with just regular resistor voltage wiring.250ma is 1/4watt which is the norm for most resitors, to get more current and light output be aware of heat issues and heat sinking.

Good luck!