Originally Posted by
southpawboston
Depending on the diameter of the lens behind the plastic lens cover of that Jos, you might be able to retrofit modern optics in there. I retrofitted just a few vintage French headlights. The IQ-TEC lens and guts from a B&M IQ Cyo premium can fit nicely in a vintage Luxor 50 (I also retrofitted the matching taillight with the guts of a B&M Seculite plus):
And a vintage Cibie headlight. This one had some generic LED and focuser retrofitted, I can't remember where I found it. The B&M was too large for this little guy:
If the reflector and bulb holder can be removed from the lamp assembly in a non-destructive fashion, I think your method is optimal. Do you just use RTV, or some other non-permanent adhesive, to mount the optics and 'tronics of the donor light? How much can be done to get the heat moved to the light's housing? That seems to be one of the problems that will unique to each light.
My little Jos light has the reflector attached to the lens, leaving a hole in the reflector that is just large enough to admit the bulb. The bulb itself mounts in a little threaded holder that inserts into the reflector assembly...
My general idea is to make an aluminum part that would fit in place of the bulb holder and would act as a mounting platform for two small LEDs wired in series. The LEDs would be aimed sideways into the reflector. The aluminum piece would serve to conduct the LEDs' heat out to the reflector and then to the light's housing. The aluminum piece would also act as the ground connection, since the reflector served as the return path for the incandescent bulb.
I expect to have the rectifier diodes mounted behind the reflector.
This is very much just in the conceptual stage right now. The goal is to be very minimal but still draw 3 watts from the dynamo.
Like some of my other electronics projects, it will end up being primarily a mechanical project. My hope is that a hacksaw and file will sufficient <fingers crossed>
Steve in Peoria