deekay911

I don't really understand why everyone wants to make this so complicated - get a set of T5 LEDs - preferably bright red, and they drop right in without additional resistors, or any wiring/track modifications at all. The little red plastic bases on these LEDs have to come off so you can spread the legs to fit the existing holes - that's when you will see they have a built-in resisitor each to enable them to work with 12V directly.

Michaelc

Any update on this thread... Are their any other options for LED lighting on our car? Turn signals, brake lights?

deekay911

You can buy LED kits for the dash as well as any of the lights. Check out ebay.

jo-hans

After talking with Andreas about the switch from White to Red LED's I discovered that when using the Resistor Calculator for these 24 LED's in a Parallel setup we end up with a required Resistor of 27 Ohm / 6 watts (see image below) versus the one used in the kit of 22 Ohm / 5 watts. This is based on the typical voltage between the 3.2V for the White versus the typical voltage of 2.2V for the Red.
I know they are a cheap replacement but the question to the guru's out there is if we should be worried about the small difference and go ahead and swap from white to red with Nick's supplied and installed Resistor?



Regards

cmat

The trouble with using one resistor to set the current through a bunch of LED's is that the LED's need to be exactly matched or the current through each LED can vary greatly. That is, the resistor sets the total current but the individual current will be set by the voltage/current characteristic of each LED. Using LED's with a built-in resistor eliminates this issue.

Elonash

IMHO I would recommend a single resistor, as if you do use the same leds you will have exactly the same Delta V, not approximately but exactly, due to the semi conductor properties of the PN junction of the led.
With red wave length you should get a delta V of 1,63V, which could get up to 2,03V with red-to-orange ones.
1.63 V is a nice value as it brings less power so you could use a smaller resistor (smaller in volume, not in value!).

Actually what I did on my car was to mount in line one single resistor with four parallel groups of four leds in serial. The tension of 4 leds is 4x1.63=6.52V, which lets 12-6.52=5.48V at the resistor, and we wants 80mA through the resistor to have 20mA in each of the fourth led groups.
5.48/0.08=68.5ohms which is perfect as we can buy a 68ohms. P=5.48*0.08=.4W so a small and cheap 1/2 W will do the work.
my 0.2cts

deekay911

Again, I don't understand why everyone is making this so complicated. Get 12V T5 red LEDs and you don't need to worry about anything else. they are direct replacements for the bulbs.

Here it is:

Elonash

You're right.
However in my case instead of the light I had a black plastic part (it's in the PET).
Don't ask me why but the car has been ordered WITH spoiler but WHITOUT brake light.

So I drilled this plastic part and mounted leds on it.

hchc

Anybody has 6 or so incandescent bulbs that they can spare? Was planning on switching to led bulbs but really would like to get back on the road as soon as possible so soldering 6 bulbs is faster than 24
Please PM Thanks!