LED help

[ImSoBored]

I know little about LED installs ,I need to know everything that I would need to know to put them in my vents. ex. what size? resistors if needed? and etc.

[freeze12]

http://www.lsdiodes.com

[johny_boy32]

i got inch neons in each of the 4 main vents...if you got any ?'s just pm me or ask here.

[ImSoBored]

can you just solder the resistors straight to the wires, or do you need one of those little green boards?

so for 6 1.7volt LEDs in a series

it would go +connection to resistor to leds in series to -connection?

where would the switch fit in?? before or after the resistor

[Cyber Knight]

No, you don't need a circuit board at all, just run 'em right off the wires.

It doesn't matter where the resistor is in the loop, it's just in there to soak up a little extra voltage so not too much goes to the rest of the componenets in the loop. The switch can also go anywhere in the loop, as soon as there is a break in the circuit, electricity won't flow thru any of it.

[ImSoBored]

resistor calculator (http://metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng)

k for the series one, I put 12, 1.7, 20, 6

got Calculated Limiting Resistor 90ohms
Safe pick is a resistor with
power rating of
.06watts

[Silentalero]

If you wire them in series then you dont need resistors.

[Cyber Knight]

Well, in series the circuit will only safely handle 10.2V (6 LEDs X 1.7V) so the resistor chosen should be perfect.

[ImSoBored]

Originally posted by Cyber Knight@Jan 22 2004, 04:37 PM
Well, in series the circuit will only safely handle 10.2V (6 LEDs X 1.7V) so the resistor chosen should be perfect.
so whos right and whos wrong?? resistor or no res?

[Cyber Knight]

I say use the resistor to be on the safe side, otherwise you might cook your LEDs.

[Silentalero]

ok in lamens terms lets say you have a 3v led now wireing them in series using 4 of them 3v x 4 = 12v line

now take a single 3v led will need a resistor to make it into a 12v line (depending on size of resistor)

wiring in series eliminates all use for resistors, just know the voltage of your leds and make sure they will equal a 12v line.


btw you wouldnt fry your leds either, they just wouldnt light up

[Cyber Knight]

But his LEDs are 1.7V each, and the total rating for 6 is 10.2V. If you put too much voltage thru an LED you will cook it, but in this case I don't know if and extra 1.8V will be enuf to cook them. The whole point of a resistor in series is to reduce the amount of voltage dropped on the rest of the components in that portion of a circuit.

[ImSoBored]

the forward voltage is a min of 1.9 typ. 2.3 and max of 2.5

that mean I can run any voltage between 1.9 and 2.5?

[Cyber Knight]

Yep, and if that's the case then you don't need a resistor at all.

[99Olds]

So you guys are saying you put leds in ur air vents. If I want to do that is it just like putting neons in ur car. And is it possible for u to puts pics of ur cars in so i kan see what it looks like

[ImSoBored]

once I get it done, ill take pictures, I still need to get the stuff

[velocity]

You gotta remember...when your car is running the voltage will be almost 15V, the voltage put out from your alternator. When the engine isn't running, your voltage can get as low as 10V. The resistor will allow you to run a couple of LEDs without them changing intensity as much. If you want them to stay the same intensity throughout the whole voltage range you need to do a little circuit work....let me know if that's the case and I'll whip up a schematic for you.

[ImSoBored]

awww dam, ^^ now someone tells me, and now it gets harder, yeah i'll be driving with em more than just sittn there with no start

[ImSoBored]

and velocity, dunno if it matters but ima be using 1.7 volts now

[Cyber Knight]

You wanna make life easy? Buy a variable resistor, it'll cost a bit more ($2?). Wire it in series, set it to max resistance, and turn on the circuit. Nothing happens, but now start tuning the resistance slowly towards zero. The lights will get brighter, so you can adjust it to how you like, when you like. If you find that they aren't bright enuf at zero resistance, then go thru the above procedure again after removing one of the lights from the circuit.

[Silentalero]

holy crap guys your gonna make him poop himself, lol

ok you wanna make life very very easy..go buy some 3v led's and wire 4 in series, no resistor no problems.

[Cyber Knight]

Originally posted by velocity@Jan 26 2004, 02:29 AM
You gotta remember...when your car is running the voltage will be almost 15V, the voltage put out from your alternator. When the engine isn't running, your voltage can get as low as 10V. The resistor will allow you to run a couple of LEDs without them changing intensity as much. If you want them to stay the same intensity throughout the whole voltage range you need to do a little circuit work....let me know if that's the case and I'll whip up a schematic for you.
According to this, four 3V LEDs will still vary in brightness.

[Silentalero]

no they wont because i have about 15 sets of 3v leds wiried in series in pairs of 4, i never have any dimming or brightness problems.

[Cyber Knight]

I've never tried LEDs, so I didn't know if there would be problems with dimming. What are you lighting up with yours Silent?

[ImSoBored]

well cant argue with silents results

thnx, proly gunna end up with 1.7volt ones

[Silentalero]

haha youve nevere seen my car?

[Cyber Knight]

Originally posted by Silentalero@Jan 26 2004, 10:34 PM
haha youve nevere seen my car?
Oops, had yours confused with a different one (one without LEDs). Don't mind me, I can see clearly now...

[johny_boy32]

lol...lets break into song....anyone know this one; i can see clearly now the rain is gone...sorry...lmao

[AleroHawk]

...I can see all obstacles in my way!