LED's - A quick guide.
01-23-2005, 08:28 PM
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LED's - A quick guide.
Although I am not into modding my car like the rest of you, I thought I could share some knowledge that might help some of you.
My simple guide to LED's
It's really simple...Most of you know the a dropping resistor needs to be used when running an LED from your cars battery. But which value is right for you?
Every LED is different; They have different operating specs and colors.
Ok, you got a package of blue LED's, and on the package it says that the operating voltage is 2.2V @ 20mA (typical). For a single LED application, take your battery voltage (13.8 not 12) and subtract the operating voltage of the LED (13.8 - 2.2 = 11.6). Then take that voltage and divide it by the operating current (11.6 / 20mA (or 0.02) = 580). So there you go, you need a 580 ohm resistor. (or the closest value to that) (Closest common value is 620)
*Note - if the value you get is not a common resistor value, move up in value, not down. Also, resistors connected in series add up in value.
Example for 2 or more LED's connected in series (using that same package of LED's smile.gif )
(Source - (LED1 + LED2 +....)) / (LED operating current) -OR-
(13.8 - (2.2 + 2.2)) / 0.02
(13.8 - 4.4) / 0.02
9.4 / 0.02 = 470
*NOTE 2 - Don't exceed 80% of the source voltage. 80% of 13.8 volts is about 11 volts or in our case, 5 LED's
LED's in parallel
In parallel, each LED will need its own dropping resistor.
Just use the rules for a single LED (13.8 - 2.2) / 0.02 = 580)
From that we can tell a 580 ohm resistor will need to be added to each LED
My simple guide to LED's
It's really simple...Most of you know the a dropping resistor needs to be used when running an LED from your cars battery. But which value is right for you?
Every LED is different; They have different operating specs and colors.
Ok, you got a package of blue LED's, and on the package it says that the operating voltage is 2.2V @ 20mA (typical). For a single LED application, take your battery voltage (13.8 not 12) and subtract the operating voltage of the LED (13.8 - 2.2 = 11.6). Then take that voltage and divide it by the operating current (11.6 / 20mA (or 0.02) = 580). So there you go, you need a 580 ohm resistor. (or the closest value to that) (Closest common value is 620)
*Note - if the value you get is not a common resistor value, move up in value, not down. Also, resistors connected in series add up in value.
Example for 2 or more LED's connected in series (using that same package of LED's smile.gif )
(Source - (LED1 + LED2 +....)) / (LED operating current) -OR-
(13.8 - (2.2 + 2.2)) / 0.02
(13.8 - 4.4) / 0.02
9.4 / 0.02 = 470
*NOTE 2 - Don't exceed 80% of the source voltage. 80% of 13.8 volts is about 11 volts or in our case, 5 LED's
LED's in parallel
In parallel, each LED will need its own dropping resistor.
Just use the rules for a single LED (13.8 - 2.2) / 0.02 = 580)
From that we can tell a 580 ohm resistor will need to be added to each LED
01-23-2005, 08:50 PM
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Vehicle: 2000/Hyundai/Tiburon
Helpful, but I'm kinda lazy about this much detail so I'm gonna have our local LED guy tibby01 do most of mine for me. Maybe If I do a couple small custom led jobs this will be of use.
01-25-2005, 09:43 AM
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Vehicle: 2001 Hyundai Tiburon, 2004 Kia Sorento, 2010 Kia Soul
Why don't you guys try writing in detail?
Saying "I hooked my led's up to the cigerette lighter, whoohoo!" doesn't help anything.
Look at the effort put into his post.
Saying "I hooked my led's up to the cigerette lighter, whoohoo!" doesn't help anything.
Look at the effort put into his post.
01-26-2005, 11:39 AM
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LoL! Redz lol :drillserg :drillserg
I got an 01 tib, and a sunroof. There is like a "unit" or whatever you want to call it, that let's me turn on 2 overhead lights, and open/close the sunroof. I took that off, and found the power that goes to one of the bulbs. It had one of those O things on the end, I can't think of the name. But anyway..
It had the O piece screwed down, so I took off the screw, and the wire was hanging free. I stripped the ends of my led wires, and wrapped them around the O piece, and the put them on a ground.
Thats the best I can do! lol
I got an 01 tib, and a sunroof. There is like a "unit" or whatever you want to call it, that let's me turn on 2 overhead lights, and open/close the sunroof. I took that off, and found the power that goes to one of the bulbs. It had one of those O things on the end, I can't think of the name. But anyway..
It had the O piece screwed down, so I took off the screw, and the wire was hanging free. I stripped the ends of my led wires, and wrapped them around the O piece, and the put them on a ground.
Thats the best I can do! lol
01-27-2005, 10:45 AM
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<div class='quotetop'>QUOTE </div><div class='quotemain'>*Note - if the value you get is not a common resistor value, move up in value, not down. Also, resistors connected in series add up in value.</div>
Actually, if anyone bothered to take high school Physics, then you'd know that when you connect resistors in series (one next to each other), you basically add the total resistance (also known as equivalent resistance).
So for your 480, you'd need prolly 400 ohm + 80 ohm...or whatever. Moving up in resistor value doesn't hurt, but you gotta make sure the power dissipation is not exceeded on the resistor. But for a simple set up like that, it shouldn't matter, since people are going for looks *cough*rice*cough* than a complex circuit.
But nice write up.
Actually, if anyone bothered to take high school Physics, then you'd know that when you connect resistors in series (one next to each other), you basically add the total resistance (also known as equivalent resistance).
So for your 480, you'd need prolly 400 ohm + 80 ohm...or whatever. Moving up in resistor value doesn't hurt, but you gotta make sure the power dissipation is not exceeded on the resistor. But for a simple set up like that, it shouldn't matter, since people are going for looks *cough*rice*cough* than a complex circuit.
But nice write up.
01-29-2005, 11:46 AM
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Ok, maybe I should read the forums some more.... smile.gif
purpletib, This was posted so you could do them yourself. Hope you do try a few small projects, just to see how easy it really is smile.gif
REDZMAN, thanks for noticing that little bit of effort in my post.
ArcticChill, You are correct, you can connect two resistors in series to increase the resistance. I should have pointed that out I guess. However, since places like radio shack only carry packs of resistors and not single ones, it is more cost effective to just jump up to the next value unless you plan to do a few LED projects. Of course if you are like me, and have tens of thousands of resistors and other components laying around, go for it. Also, the great thing about LED's is the small package size of the LED itself. If you are working with limited space, more then one resistor (although they are very small) may make the project more difficult than needed.
Everyone else, If you hooked them up some strange way and they work fine, then I wouldn't worry too much. Without knowing exactly what you did, most cases of bad hookups would only result in short LED life, low light, or a few quick LED failures. There may be a few rare cases that damage to other then LED's could occur, VERY rare cases... smile.gif
purpletib, This was posted so you could do them yourself. Hope you do try a few small projects, just to see how easy it really is smile.gif
REDZMAN, thanks for noticing that little bit of effort in my post.
ArcticChill, You are correct, you can connect two resistors in series to increase the resistance. I should have pointed that out I guess. However, since places like radio shack only carry packs of resistors and not single ones, it is more cost effective to just jump up to the next value unless you plan to do a few LED projects. Of course if you are like me, and have tens of thousands of resistors and other components laying around, go for it. Also, the great thing about LED's is the small package size of the LED itself. If you are working with limited space, more then one resistor (although they are very small) may make the project more difficult than needed.
Everyone else, If you hooked them up some strange way and they work fine, then I wouldn't worry too much. Without knowing exactly what you did, most cases of bad hookups would only result in short LED life, low light, or a few quick LED failures. There may be a few rare cases that damage to other then LED's could occur, VERY rare cases... smile.gif
02-10-2005, 12:27 PM
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sorry redz... I have 3 single led's in my car and 1 neon bar. 1 LED in each door handle and one in the back of the little tray under the radio. (looks pretty cool cause it shines through on my shifter.) The neon is right under the cushion on my back seat. I ran all the wires singley to the where the cigarette ligher is.
I took the Cigaretter Lighter out, and replaced it with a black rocker switch with a red Led in the top to match my leds and placed it in the hole where the cigarette lighter used to be. Perfect fit, the switch was like 3.50 at advance. ran the wires from the leds to my switch and Viola. I'm batman with secret switches. Plus all my friends call my car the bat mobile. So I AM BATMAN!!
note: I hooked the switch to the amp. Dont know if that was a good idea but they go off when i turn the car off..
I took the Cigaretter Lighter out, and replaced it with a black rocker switch with a red Led in the top to match my leds and placed it in the hole where the cigarette lighter used to be. Perfect fit, the switch was like 3.50 at advance. ran the wires from the leds to my switch and Viola. I'm batman with secret switches. Plus all my friends call my car the bat mobile. So I AM BATMAN!!
note: I hooked the switch to the amp. Dont know if that was a good idea but they go off when i turn the car off..
