Tail light rebuild project questions

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Thread Starter


Joined Mar 11, 2010
Hey all, first time post but i've been doing some reading on here. In fact, thats the only reason i've gotten this far. I'm rebuilding a tail light on my dirt motorcycle for visibility purposes at night. My current one is shot and I'm just re-using the housing.

I have Lumiled superflux HPWT-DH00
I'm going to be running 4 sets of 4 LEDS in 3 rows. (see picture)

I'm having issues with what size resistors i need. I've come up with this.

vF = 2.19 - 3.03 = avg 2.61v
4 LEDS x 2.61v = 10.44v drop
Max forward current - 70mA

14.5v - 10.44v = 4.06v / 70mA = 58ohms
12.7v - 10.44v = 2.26v / 70mA = 32.28ohms
11.5v - 10.44v = 1.06v / 70mA = 15.14 ohms

I dont want to blow the LEDS, nor shorten their life, but would like them as bright as possible.

What resistors should i go with?
What do i need for a brake light high/low ?
Do i need the continuous forward current?
Where can i draw up a schematic (link)?

here's a picture. any help is great as i'm sure i'll be needed more along the way. Thanks!

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