3 Watt LED Bike Light
June, 2008, Rev e
Prototype 14 – Triple Cree with 8 degree Optics
The Prototype 6 uses L2 Optics for a beam pattern that is adjustable with the sub lens diffusers. One difficulty in making that prototype is filing the L2 optic base to accommodate the LED power wires. An alternative is to use optics that do not cover the contact points on the star base. Not a lot of choices were available but item DX SKU-1920 or KAI SKU-1503 are 8 degree optics. These work well in small flashlights but I wanted to see what they would do in a bike light where spillover might make the narrow main beam adequate. The basic construction of the light is exactly as Prototype 6 with the same Luxdrive 3023 Buckpuck in the pre-wired version used with an external pot for brightness control. The snap on lens can be seen in the last photos, which are specifically designed for the Cree LEDs. The last photo shows the optics bonded to the base with urethane glue. This variety bubbles when it dries but works fine.
The prototype uses a 12 volt gel cell for power and is the same as Prototype 6 with different lens. The final prototype is shown below. The beam pattern (shown under the Light and Beam Measurements section) is quite narrow and very bright. There is spillover, but I think this beam pattern is only useful on long straight roads, not on twisting roads or paths. It does keep the light low and less offensive to oncoming cars.