So I'm in the process of replacing all bulbs in the car with LEDs (thanks to Daryl Nilsen for the DIY), I have replaced interior lights, both front and rear, front turn signal, license plate and a little lateral bulb in the taillights. So for the rear I drilled my taillights and added 29 small red LEDs, (note* they turn on when the Lights are on NOT when I hit the brake) it looks nice (dark red) however I'm having a problem here. I know the basics of electronics so if there are 29 LEDs (20 mA each) and the voltage is 14.4 while driving, then using
V=IR
P=(V^2)/R
R= V/I
R=14.4/(.02*29LEDs)= 24.82 Ohms As I couldn't find this resistor I used a 25 Watt 27 Ohms for added safety.
The resistor is dissipating about 7.68 Watts MAX (14.4^2v/27Ohms), but I noticed that only after a few minutes of having them on, the resistor gets too hot, the tape I used hasn't melt but it is really hot, I don't think this is normal because the LEDs I got for the turn signals use 9 LEDs and little 1 watt resistors. Feel free to ask for pics and schematics. I just don't feel safe driving, it could start a fire in the trunk. Thanks in advance guys
V=IR
P=(V^2)/R
R= V/I
R=14.4/(.02*29LEDs)= 24.82 Ohms As I couldn't find this resistor I used a 25 Watt 27 Ohms for added safety.
The resistor is dissipating about 7.68 Watts MAX (14.4^2v/27Ohms), but I noticed that only after a few minutes of having them on, the resistor gets too hot, the tape I used hasn't melt but it is really hot, I don't think this is normal because the LEDs I got for the turn signals use 9 LEDs and little 1 watt resistors. Feel free to ask for pics and schematics. I just don't feel safe driving, it could start a fire in the trunk. Thanks in advance guys