LED wiring guides.

[ShawnS]

Anyone know of any websites that guide you through the process of wiring in LED's for automotive applications? I want to convert my HVAC controls to LED and I can figure out this resistor thing.

[Dean]

Check out this page and see if it helps...

http://www.kpsec.freeuk.com/components/led.htm

Basically, LEDs are short circuits, and will destroy themselves, and/or the power source in short order if you don't add resistance in series with them. The formula lower on the page will tell you what value resistor you need. Unless you are on a regulated line, assume car voltage is 13.7 volts I think.

[ShawnS]

Thanks Deano


So if I had an unregulated supply going into the controls at 13.7v and used a white led, the resistor value would be 485 ohms?

[sperry]

Originally Posted by ShawnS

Thanks Deano


So if I had an unregulated supply going into the controls at 13.7v and used a white led, the resistor value would be 485 ohms?

It depends on the LED... they do take a specified voltage. You can put them in parrallel to match the car's voltage instead of using resistors... why convert some of the power to heat when you can convert it to more light!

When I did my gauge cluster, I used groups of 6 in parallel to match the battery voltage (I was assuming 12V, and the LEDs were 2V's each). They worked well as far as light output, but didn't look all that good because the light from the LED's was too directional compared to bulbs.

[Dean]

Originally Posted by sperry

It depends on the LED... they do take a specified voltage. You can put them in parrallel to match the car's voltage instead of using resistors... why convert some of the power to heat when you can convert it to more light!

When I did my gauge cluster, I used groups of 6 in parallel to match the battery voltage (I was assuming 12V, and the LEDs were 2V's each). They worked well as far as light output, but didn't look all that good because the light from the LED's was too directional compared to bulbs.

If you read that page I linked to, you will see that hooking up LEDS in parallel is not a good option. One with slightly lower internal resistance will take more of the juice, making the others dimmer, and shortening it's life, and when it goes, the rest will be taking more than there share of voltage and you cascade into darkness.

[sperry]

Originally Posted by Dean

If you read that page I linked to, you will see that hooking up LEDS in parallel is not a good option. One with slightly lower internal resistance will take more of the juice, making the others dimmer, and shortening it's life, and when it goes, the rest will be taking more than there share of voltage and you cascade into darkness.

Sound's legit... but I didn't have any issues w/ mine for the few months they were installed.

'Course, they looked like ass anyway because the reflectors in the gauges are designed for bulbs, which is what I promptly returned to using... so I didn't really get to test the longevity of the LEDs.

[ShawnS]

Originally Posted by sperry

Sound's legit... but I didn't have any issues w/ mine for the few months they were installed.

'Course, they looked like ass anyway because the reflectors in the gauges are designed for bulbs, which is what I promptly returned to using... so I didn't really get to test the longevity of the LEDs.

I am not looking to convert my cluster to LED's for just that reason. I will will be going with some PIAA superwhites. I am just interested in the dash controls shown here.

[MikeSTI]

cant you just get the bulb condoms for that?

[sperry]

Originally Posted by MikeSTI

cant you just get the bulb condoms for that?

That's how I converted mine to red.

But if you want to go blue or white or something really bright, you need to go w/ LEDs since bulbs put out yellow light to begin with. Blue condoms look green/aqua, not blue.

[MikeSTI]

that sucks ...........what if you double wraped them?

[sybir]

The buls put out so little power that you'd get no light at all.

That's why the clear bulbs show up yellow, they're not bright enough.

Same thing with turn signals. Clear bulbs will still be yellowish.

[ShawnS]

Originally Posted by MikeSTI

that sucks ...........what if you double wraped them?

That would decrease the amount of light that is visable and change the output to a dull blue.


I am looking to go white for everything and leave me gauge needles red. That way when I get my defi setup, everything will match. I would change everything to green to match the STACK gauge setup, but STACK doesn't have a meter that reads MPH.