Originally Posted by
steelbikeguy
...
I've had much, much better results with some of the molded optics, especially those from Ledil. My Cateye Micro II conversion is an example.
I've seen reports of conversions of "classic" headlights where the LED was simply placed in the location where the bulb had been. They did look nice, but I have doubts that the beam was equivalent to what can be obtained with molded optics. The problem of heatsinking the LED is tough to solve too. The best case scenarios are to add some venting to the case to direct air to an internal heatsink, or try to create a thermal path from the LED to the steel case, or to try to create a thermal path from the LED to an aluminum handlebar or mounting bracket that can serve as a heatsink.
Sorry, I got the model# wrong, it's the even older HL-200 that uses D-cells.
I find battery-life is still an issue with lithium cells. Lights keep on getting brighter and they consume more power, so batteries are always playing catch-up. A Cree XML-2 @ max-brightness (~600-800 lumens OTF) uses about 10w and that'll deplete an 18650 battery in about 20-30 minutes. Using 4 of them gives me the 2-hrs I need. I don't like having separate batteries and their wiring snaking around the bike, so I prefer standalone lights. Easier to transfer to another bike as well.
For converting the HL-200, I'd scrap the reflector and use an XML-2 drop-in. Keep the stock lense as the fluting does a good job of spreading the beam sideways. Then attach the pill to a finned heatsink that I cut out a rectangular hole on top for. Or if you prefer to spec separate LED & driver from KD, DX or your vendor of choice, then you can make your own copper-slug to attach them.
