Homebrew Led Headlights

For the last few weeks now I have been toying with the idea of building a set of LED headlights to see myself through the winter. The Audax UK site has some good links to some good lighting articles but the technology is changing that fast a lot of it is starting to look dated.
I’ve already got some 15 degree lenses from Hong Kong and I’ve got some 3W and 5W LEDs on the way too.
I paid 45 pounds for a Cateye EL530 light and although its bright I’m not happy with it.
A LED torch rated at 5W from Hong Kong but more like 0.5W has a similar output but a wider beamspread. Take off 17.5% Vat and the shops markup and your looking at prices that are quite cheap as the component value is minimal.

At the top end of the market things  are a bit different but the savings are higher. From what I can gather it is a blend of light output versus battery life. I bought 5 lenses for $3 which should see me OK for a while. There is a whole home brew community out there I might as well add my 2cents worth.

The thing is that things are changing as we speak, higher output LED,s are coming on to the market all the time. Li:Ion battery technology is increasing all the time too. It’s just a matter of where you source your components.

I have no problem with buying from the far east on Ebay it has all turned up if a little slowly.

To be continued with links, pics, articles  and whatever.
The LEDs are taking some time to come through but it’s early days yet.
16 Dec 07 I’ll be buying some LEDs off Farnell or RS components as I don’t think these far east ones are going to turn up. At least I will know what I’m getting from a UK supplier. I’ll be using an off the shelf LED driver for it as the allow you to set different currents and incorporate flashing modes too.  I’m not looking to reinvent the wheel just get a setup that is cheap and bright enough to ride in the dark.
 

The first 3 watt led has turned up from China with a 5 watt 192 lumen on it’s way. The fun starts now with driving the 3 watt one. It is a Luxeon star from Lumileds and the lens fits tightly over the emmiter. It is now a case of mounting the lens and led on a heatsink sorting out a current source. The 3 watt LED is rated at 80 lumens. More to follow.

Had a spot of bother with the first test of the 3 watt Led. I ended up blowing the thing up playing around with driver currents while monitorin the forward voltage. What is apparent with the 3W Leds is that twice the current does not mean twice the light output. I’m looking at throttling the current back and maybe doubling the battery life.

What is also apparent is they are operating right on the limit. Go over the limit and it is the worlds fastest fuse. Also they need a good lens or the light is just wasted. It was with when I was playing around with a torch reflector that it went pop. 

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