LED Foglight Project Options

[Spoke]

The design of an early foglight LED board has begun. mepstein sent me a couple of foglight fixtures to use to design the board. 2 main issues are fitment and heat dissipation. If things work out ok the design should be able to be re-laid out for the later square foglight.

The board will have 8 Cree XP-G3 high power surface mount LEDs with 350ma current each. These will burn about 1W of power with a total power dissipation expected to be less than 10W. Hopefully these will be almost as bright as a headlight.

Each LED will have its own focusing lens. The lenses are Carclo 10192 elliptical 20mm lenses. The light pattern for the 10192 lens is shown below.



This is the spectral dispersion for the lens.

[914forme]

PDBs going to be green or black in the final version?

[Spoke]

PDBs going to be green or black in the final version?

The first boards will be white. I used white for the 356 lights. Here's the first 356 PCB I did as I was mounting the LEDs. These are a PITA since they are surface mount. I would tin the pads then while holding the LED with tweezers, heat the the pad with air and when the solder liquified I'd drop the LED in and wait until the solder re-liquefied then remove the heat. I would do 3 LEDs at a time then test them to make sure they were soldered correctly.

For these boards I'll use solder paste and an infrared reflow oven to put the LEDs down. Then the board will be flipped and the converter components will be mounted using solder paste and hot air.




These are the Carclo 10192 elliptical lenses; one for each LED.

[ClayPerrine]

PDBs going to be green or black in the final version?

The first boards will be white. I used white for the 356 lights. Here's the first 356 PCB I did as I was mounting the LEDs. These are a PITA since they are surface mount. I would tin the pads then while holding the LED with tweezers, heat the the pad with air and when the solder liquified I'd drop the LED in and wait until the solder re-liquefied then remove the heat. I would do 3 LEDs at a time then test them to make sure they were soldered correctly.

For these boards I'll use solder paste and an infrared reflow oven to put the LEDs down. Then the board will be flipped and the converter components will be mounted using solder paste and hot air.




These are the Carclo 10192 elliptical lenses; one for each LED.

I used to do component level repair on computer motherboards. We would desolder the offending surface mount chip, tin the contacts on the replacement chip, and use a drop of super glue to hold it in place. After that, less than a minute in the hot air machine and it would be soldered.

That was 26 years ago. Maybe technology on how to install surface mount chips has changed.