Harbor Freight sells these cheap incandescent headlamps for like $3.00. For what they cost they are not half bad. Still, I’d prefer an LED over the incandescent bulb.
I had one of these Harbor Freight headlamps (HFHL) and a broken LED flashlight. The flashlight used a 1 watt LED mounted to an aluminium PCB. The flashlight’s driver still worked too so I used it and the LED to convert the HFHL.
I removed some of the guts (plastic bits) from the HFHL to make room for the new LED, heatsink and driver.
I initially tried it without any sort of heatsink bu, it had “heat management issues.”
So, I added a piece of aluminum from the donor flashlight as a heatsink. I hot-glued the driver to the bottom of the heatsink (covered it in electrical tape to prevent shorts). I tacked the LED to the heat sink with hot-glue and did the same with the reflector. Before tacking the LED in place I added a bit of thermal compound to the bottom of the LED for good measure.
I had to drill out the hole in the reflector so the LED would fit.
After adding the heatsink the temperature stayed reasonable but I drilled some holes in the top of the case so heat could escape.
Works pretty well.