Put together a light for the mountain bike.
Its 4 cree Q2's shining through OPTX optics driven by bflex driver. Running 2 strings of 2 in parallel.
I wanted something with a broader beam than on my road light ( http://www.candlepowerforums.com/vb/...d.php?t=171415) for the twisty trails...but also a narrow beam for when Im riding to the trails.
So I designed it with two leds facing forwards and two down and to the sides. Made a little mounting plate and bent the ends up. Note if you use thermal epoxy to stick the LEDs on, and then twist the mounting plate, they will pop off!
Had to hack part of the lens base to fit...these LEDs only have two contacts on each side not 3, the third one would fit in the space in the optics base.
There should be another contact between the two + +
Optics glued on
I measured the Vf of each LED and divided them into two lots with the same total Vf so they should run at 500mA each driven by the bflex at 1A.
The forward LEDs are directly driven (cause I always want to see whats in front) but with the side ones I can switch in a 3ohm resistor that limits their current to around 300mA(boosting the forward ones to 700mA).
Thermal epoxy sticks em to the mounting plate which then is epoxied inside a rectangular aluminium section.
The origninal idea was to put the bflex driver in there too but was getting a little cramped and I couldn't think of a nice way to make a remote switch mount.
The ends are sealed up with carbon fiber. Its not a tight weave and the idea was some light would shine out giving me some side visibility. Worked really well on my road bike light (just epoxy and good side viz)but the carbon blocks most of it here.
Mylar covers the holes in the front and the wires exit through a gromit that I will bung up with silicon. Should handle the mud well.
A small aluminium stem bolts the light head to the front mudguard mounting point and the bflex controller and switches live in a small box on the handlebar stem (same as my road light but with the extra switch for dimming the side lights). All powered by 12 AAs.
The beam was surprising. I didnt expect it to be nearly as good.
Testing on the bench it was obviously a little wider than the genuine cree optics and the leds pointing down there is always a lot of light close up.
There is not much difference with or without the side lights dimmed so I will increase the resistor in there.
I am pretty stoked with it and may bolt it to my road bike. Maybe a helmet mount for the suddenly obsolete dual cree road light....
LEDs from www.kaidomain.com
Bflex driver from www.taskled.com
Optics from www.luxeoncanada.com
Bits and bobs from dicksmiths electronics.