making a cheap Luxeon dome light?

[Turbo_E]

i have an idea, thats probably been discussed before.

due to the massive drop in the cost of LuxIII's i bought a bunch. now i was thinking of having 2 emitters on a heatsink beind direct driven from my car's 12-14V DC. what would i need to bring the power down to what i need? resistors?

BIN are SX1K.

given that the Domelight already has a fluted/diffuser the LED wont be TOO intense.

 

[ktronik]

would 4 emmiters fit?? as you could hook them up in series with no dropper resistor...this would be better as ballast resistors are a bit of a waste of power...

if you use only two, you would have to use a BIG 5w resistor, even if driving them @ 600ma...

food for thought...

enjoy

Ktronik

 

[chimo]

Here's an example of something that has been done.

Paul

 

[modamag]

turbo_e: It does not really matter what bin cause you're not doing white wall hunting so nobody will ever see the difference. Vf also doesn't matter since your car battery got more than enough, you're replacing a 10W bulb with a 3W LED And even Lux is not that much of an issue. I barely notice the difference between an S -> T bin under normal conditions. Almost any LuxIII you choose will be brighter and whiter than that inefficient 10W halogen bulb.

Here's what I did when I first joined CPF --> Luxeon Dome/Map Light Upgrade

Originally I used a 1x CC1WA & 1x TY0L for each bulb replacement. However the inductor on the CC1WA was causing interference with my remote so I later changed it to a LM317 + resistor (for 500mA output) + 2x LuxIII clones. It's brighter, cheaper and no interference.

Best of luck on your project.

ktronik: 4x LuxIII at one location might cause a thermal issue when you leave the door open for 20+ minutes.

 

[BatteryCharger]

Look into making an LM317 constant current driver. (search here and you'll find lots about it) It's extremely easy to make (just an LM317 and a resistor) and will drive up to 3 luxeons in series from 12v, at whatever current you decide to use.

 

[PhotonWrangler]

I would definitely drive it from a regulator, or at the very least put a 14v zener diode across the power input. A car's electrical system is pretty noisy and I wouldn't want a high voltage transient to find it's way into that Luxeon array.

 

[Turbo_E]

thanks guys