How about a simple PWM circuit as a dimmer to adjust the brightness as necessary? You could leave is relatively low for normal use to avoid blinding people and still be able to have full brightness when needed to read something, find something you dropped, etc.
Actually, I have 4 LEDs in parallel, and the brightness is just fine! I also took some book lights and hardwired them into the map light ckt to get an 'adjustable beam'. They work pretty well, too. I did this because I was delivering newspapers at night and wanted a light to see without lighting up the whole cabin. it worked great!
Hmmmm...this looks *REALLY* good! ;)
And you still didn't tell me how you did it!
Well PWM at low frequencies at low intensities flickers like crazy and gives people headaches. Not ideal if you're trying to read or have motion in the cabin.
I opted instead to keep the two side lights as low-intensity LED and the center lights (door triggered) as super-bright 1200-lumen units (the combined intensity of the front and rear door lights is about 100 lumens, just for reference). That way the map lights will be able to be used to actually see without ruining night vision if you want to.
Pics here:
Phil
10W resistors using the calculators that you mentioned above, and $5 CREE emitters from dealextreme.com. I would estimate that the brightness in the car is about 15 times brighter the stock incandescents, and they use slightly less power. The CREE emitters emit about 200 lumens each, three in series in each group with 3.6V each, about 10.8V, and the remaining 3V is taken up by the 10W resistor. 1200 lumens vs. about 104 lumens seen here:
Phil
Check out the PIAA dome light. It is a simple swap.
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