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This is the latest version of my twin Luxeon bicycle headlights. (Versions one and two and four and five (HID))
I use two 5 Watt Luxeon Stars with narrow beam lambertian lenses. The Luxeons are bolted to the copper plate with two 3mm screws. I used copper because I only had thin aluminum and wanted better heat transfer and had the copper handy. With thicker aluminum you could tap the holes with a 3mm thread. To prevent the screws from shorting to the LED board I used plastic washers made from heatsink screw insulators with the bottom part sliced off with a sharp knife. The circular lens holders are made from some PVC electrical conduit reducers but PVC water-pipe will do just as well. It's important to get the height of the lens holders exactly right so that the lens sits just above the LED but doesn't actually touch it. If you use a thin layer of silicon glue under the PVC tube and use that to get the lens spacing right, just push it down and let it set. The lens and PVC is simply glued on with a small amount of silicone glue. The lenses have a small locating protrusion on them which I filed off. When mounting the LEDs to the aluminum I used a bit of heatsink compound to improve heat transfer. The wires from the LEDs come out through holes drilled in the aluminum.
To hold the aluminum plate to the handlebars I used a plastic electrical conduit holder (25mm I think).
The mounting bracket is in two parts, this makes it easily changeable for other situations. The two parts are held together with four 3mm screws. The front of the mounting plate acts as a shield to prevent glare direct from the lights. The beam width is fairly wide so I haven't had any need to have sideways adjustment of the lights.
I've taped two switches on the downtube of the frame. I really need a prettier arrangement for the switches. On my road bike I don't have any switches but for long mountain bike expeditions I like to have the option of using one light or the other or both. For uphill or slow riding one light is enough.
The design is functional rather than pretty, when you're a long distance from home and it's dark you need reliability. I like the KISS principal, (Keep It Simple Stupid!)
The battery is 2.5 amp hour NiMH made from 10 cells (which gives 12 volts). This gives about three hours of light running both lights and close to six hours using just one lamp. I also have a 4 amp hour battery. I used good quality batterys with solder tags and made them myself. I just used a lot of electricians tape to hold them together. I use polarised plugs on connection from the battery to the power pucks so that I can't get the polarity reversed. I once ruined a puck by getting the polarity wrong. the charger connection also has a polarised plug so I can't reverse charge the batterys. (Don't forget the golden rule, spend more money on a good charger than you do on the batterys. They'll last a lot longer if you do!)
The mount on the right is for the GPS.
The two switches are taped on the downtube and the battery is in a cut off water bottle.
