quad XR-E bikelight

jamieson

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Here are some pics of the bike light I've been working on. It has four Cree XR-E leds running at about 400mA using the Fatman boost driver. Since these leds are from the P3 bin it should be up over 300 lumens. Power consumption is about 4.75W. Cree optics are used. With no airflow it gets warm to the touch after 30 minutes or so.

Riding a bike with lots of airflow it could probably get cranked up to 750mA drive current (~500 lumens) without overheating. Machined from a solid block of aluminum. My first attempt at machining.

I'll post some beam shots later. It completely blows away my 15W halogen flood light. It's amazing to get this much light and only drawing 5W.

cheers,
jamieson

DSC_4209s.jpg


The corner got munched when it slipped out of the vice. I plan to countersink all the screws tomorrow.

DSC_4212s.jpg



DSC_4213s.jpg
 

jamieson

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Currently using 4 x AA 2500mAH NIMH and getting over 2 hours runtime. The cree optics are about an 8 degree spot. A perfect blend of spot and flood for biking IMO.
 

daq

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Very nice.

Are you planning this to be helmet or handlebar mounted? How will you mount it?

I'm working on a 3x XR-E light right now, but since I can't solder worth beans (I'll blame it on my iron) it's taking much longer than I hoped/expected.

Dale
 

Brum

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daq said:
I'm working on a 3x XR-E light right now, but since I can't solder worth beans (I'll blame it on my iron) it's taking much longer than I hoped/expected.
If you are using the bare emitters, even with a $$$$$$ Weller soldering station, it aint easy. I had a friend solder the emitters, and he thought they were a ***** to solder, and his weekend job is mainly soldering SMD parts, so its not like he doesnt know how to do it.


@TS: nice light! I like the idea of using a lower power per led, thus having a higher effiency, nice! I was also thinking of building a quad XR-E, but without a boost driver the total Vf would become a problem, since you'd need a 15+V batterypack. So I stuck with a triple light.
 

chris_m

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Don't see why a boost driver is such a problem when the Taskled Fatman is readily available.

Anyway, nice light. My next build will be a quad, but with Ledil square optics, since they seem ideal for such an application (and also allow easy access to the top contacts on an XR-E emitter, making mounting the LEDs a lot easier). Though I plan on running at 700mA out of the blocks with a decent heatsink, and I'm also waiting on Q2 or Q3 bins for 600lm!

Regarding drive currents, my current triple light run at 700mA https://www.candlepowerforums.com/threads/147395 gets pretty warm in 5 minutes or so sitting on the bench, but when in use outside just moving around, not even running or biking it remains totally cold - I think I may have even got overkill on the heatsinking. If it's taking 30 minutes to warm up on the bench, I reckon you should be totally fine running at 700 or 750mA on the bike (and I wouldn't even be too scared running it on the bench at that).

Just a quick question - do you have additional windows over the optics, or is the sealing OK without? Those optics holders have holes in them, but I guess it's easy enough to seal them with a bit of silicone sealant if necessary - probably worth doing that I'd suggest if you haven't already.
 
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jamieson

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as for mounting I'll try to use some cateye parts. they have a pretty good system that will work on the bars and helmet mount.

The optics are covered by a sheet of polycarbonate. it's a tight fit but I'll probably use some caulk too.

I bought the crees soldered onto stars so soldering was a snap.

-j
 

p97z

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Nice!

Is that aluminum several pieces or one solid piece?
 

jamieson

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The main body is 2.375" x 2.375" x .75 and there is a 0.125" thick piece of aluminum on the back and a 0.125" piece of polycarbonate on the front. I drilled four 15/16 holes in the main body and then hollowed it out on my vertical mill. The hollow area is where the fatman driver board is mounted.

The four LEDs are in series. At 400mA the total drop is about 13V. The fatman driver board is rated up to 16V so I should be OK.
 

Doh!Nut

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As was "suggested" in CrisM's post there was no real need to cover the optic with polycarbonate - especially that thickness.
The efficiency of the optic is around 90% using optical grade plastics.
If you milled 1mm off the face of the alloy and cut four holes in the polycarbonate face plate you would save a bit of weight and get another ~5% more light out.

N
 

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