Converting a BISY-FL headlamp from halogen to Luxeon I LED

This set of web pages is divided into four sections:

1. Pictures of the modifications to the BISY headlamp assembly

2. Pictures of the light patterns of the stock halogen and Luxeon I versions

3. Reference pictures of the light patterns in #2, but with different camera settings for white balance. You should look at #2 first.

4. Related headlamp topics

Summary of the work and results to date:

• At the time the light-pattern photos were taken, two of the four BISY-FL headlamps have been modified. All four have now been modified, and perform very similarly.
• The modification is straightforward but the design and fabrication required considerable time. Like most home projects, it helps if you don't put a price on the cost of your time investment!
• A metal lathe would have greatly simplified the job and improved the appearance of the internal parts. If others want to give this a try, perhaps someone on BikeCurrent has a relationship with a machine shop willing to make small quantities of turned parts at an affordable price.
• Photos document the differences between the stock halogen performance and the Luxeon I performance. They are similar, but differ in some respects which the pictures attempt to convey. The light output is roughly comparable but the Luxeon version uses about 1/3 as much power. The character of the LED light is much bluer since I used the 8000K version. The over-volted halogen light is probably in the 4000K region, with a lot more red and yellow content.
• Heat-sinking for the LEDs turned out to be straightforward and effective.
• I'm using a TaskLED nFLEX constant-current regulator for the LED lamps, fed by a battery consisting of 4 Li-Ion cells in series with a BatterySpace protection circuit. The nFLEX appears to be a very effective and modest-cost approach ($25 each). I was lucky on the batteries, dismembered a couple of free laptop battery packs full of 18650 cells and most of them were OK.
• The light-pattern pictures were taken with the halogen-equipped BISY lamps driven in parallel from an adjustable regulated 6.8V DC supply. The corresponding pictures for the LED-equipped BISY lamps were taken with the lamps driven in series from the series stack of four 18650 LiIon cells via the TaskLED regulator set for 350mA.
• Testing with a Schmidt dynamo hub in a test fixture shows full brightness for two LED-version BISY lamps fed by the TaskLED regulator (and no battery pack) at simulated speeds above 9-10 miles per hour. See the cautions in the "related headlamp topics" section if you get tempted to try something like this.
• Initial testing with the Schmidt hub also shows the ability to run the two lamps plus charge the battery pack at speeds in the 15 MPH-and-up range, or perhaps a bit lower. Or charge the battery alone at speeds of 10 MPH and up.
• I don't have the lamps on the bikes yet, nor the taillamp assembly with brakelights completed. More to come when that's done.

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