# I need help with LED's for a custom tail light project.

Now Its just been a long time since I went to ITT so bear with me.

LED's 2.0 v x6 with a 12vdc power supply will not need any resistors since the voltage is being equally divided correct?

Im trying to wire these to run as tail/stop lights. Ill be using a PWM for the tail lights. But for right now I need to get this math done correctly.

If I keep thing divisible by 12volts (6 LED's) will that solve this?

So I can have 18 lights in the small ring, and 24 in the large one?

Any help here would be great!

Again this is running off of a car electrical system 12vdc.

I found this understated webpage that helped me immensely. ledcalc.com

Using, 2vdc LED's at 100mA each I have two arrays per tail light assembly.

The first array is 24 LED's, the second is 18. At a 2 vdc drop per LED I run 6 of them in series with a 22ohm 1.4 watt resistor. So for the larger array thats 4 x 6 = 24, so 4 blocks of 6, and 3 x 6 is 18, so on the smaller array I use 3 blocks of 6.

And your also correct that the voltage supplied via a cars alternator can be as high as 14volts. So that was used as the base voltage to figure out the resistor value.

Now, Im already past proof of concept stage and into final design modifications for these lights. I used a jeweled plastic coaster from the nugget casino over the smaller array to act as a diffusor giving it the look of the GTR tail lights, but with an outer ring of led's to grab the attention of the guy behind you.

Steve