Added Schematic. Hope this helps. Parts: (Total Price ends up being around $207 depending on sorce of materials.) ...
FIRST POST!! Last year I set out to create a MTB light (Helmet and Bar) for trail riding without breaking the bank and with reasonable tooling and parts sourcing. Everything here was sourced from Fastenal, Newark Electronics, Battery Space and LED Supply.com To say the least, I'm very happy with the results and have even sold MANY of these. The only power tools used were a miter saw (with non-ferous blade), drill press, dremel tool and sander (for finish work.) hand tools and a soldering iron as needed. I had a calibration lab measure the lumen output for this item over a period of time and the average output was around 1125lum per setup. I'm driving these MC-E LED's at 700mA each (separate driver for each one) which would equate to 1400lum but once you figure in heat, optics, etc, you have a bit of loss. Batteries are 14.8V 4.4AHr Li-Ion which are great and I'm running one spot and one flood lens on each setup (run time has been full power for >3 hours without noticing any loss in light output). Mount was from a $3 flashlight from eBay. Driving the LED's separatly has a couple advantages, main one for me is if one goes out,... you're not in the dark :-)
The first and most critical cut is slicing the main aluminum box - the cut is made the exact thickness of the LED's plus the lens and housing to hold them tight (no glue for the lens so you can change later if needed. I used 80/20 Inc extrusion to hold the work while cutting
Step 2: Heat Sink
Second most critical part - the heat sink. YES, if you stop pedaling with these lights (since you're driving them at 700mA each) they WILL heat up and get dimmer - pedal faster ;-) The heat sink is simply aluminum bar stock with slits cut - i used spacers in the holder to align them equaly. Bevel the edges afterwards. Sand with 220 to get a smooth finish for later mounting the LED's