custom led strips?

Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=112466
Printed Date: May 02, 2025 at 10:29 PM

Topic: custom led strips?

Posted By: fragydig529
Subject: custom led strips?
Date Posted: March 18, 2009 at 3:12 AM

To start, my car is an '01 Chevrolet Impala.

Well, I'm kinda a novice at car wiring, but I recently came into a ton of green LEDs, and green being my favorite color, I decided I would try to make my own LED strips to replace my current green neon kit in my car.

Got to thinking about it a bit, and for some reason, I'm confused. It's probably an easy answer, but for some reason I can't figure it out.

Here's the info on the LED

Reverse Current (uA) : <=30
Fv: 3.0v - 3.4v
Life Rating : 100,000 Hours
Max Power Dissipation : 80mw
Max Continuous Forward Current : 30mA
Max Peak Forward Current : 75mA
Reverse Voltage : 5~6V

I was reading alot about resistor this, resistor that. I came up with a few basic wiring diagrams.

posted_image

Now, I'm pretty sure all of these will work, not 100% sure on that. But the problem I was having was with paring these up... For some reason I can't figure it out. I want each strip to have 12 LEDs. Meaning that with Diagram 1, it'd take 3 "strips". Now do I need to wire each of the 3 strips to a common positive wire?

Like, how exactly could I get 12 LEDs on a strip in a series, without having 3 positive wires, and 3 negative wires? I'm sure I'm just being a moron. A diagram would be greatly appreciated. Thanks =D

Replies:

Posted By: i am an idiot
Date Posted: March 18, 2009 at 5:49 AM

Diagram 2 or 3 will work fine. Diagram 1 will fluctuate in brightness with alternator output. And the LEDs will not be as reliable.

Posted By: KPierson
Date Posted: March 18, 2009 at 6:01 AM

I personally would go with #3 - that way if you have a problem with one LED no other LEDs will be affected. It will be a few more resistors, but in the long run it will most likely be worth it.

Your max forward current is 30mA and if you assume a max system voltage of 15 vdc your resistor value would be 500 ohms which would make it a 520 ohm resistor I believe. 470 ohms can result in an overcurrent situation and could shorten the life of the LEDs.

-------------
Kevin Pierson

Posted By: fragydig529
Date Posted: March 18, 2009 at 12:14 PM

Ok, so I'll go with the 500 Ohm resistor per LED setup. Does the wattage matter?

And to put my question up again.

How exactly can I wire these together into sets of 12?

I know it can't be

(+) --RESISTOR---LED---RESISTOR---LED---RESISTOR---LED---ETC-- (-)

Do I need to do something more like this

    - RESISTOR - LED - (-)
    |
(+) - RESISTOR - LED - (-)
    |
    - RESISTOR - LED - (-)

But to make a strip, that is going to take alot of wire.
So how would I go about putting these things onto a strip?

Posted By: KPierson
Date Posted: March 18, 2009 at 12:29 PM

I would probably do it on a proto circuit board. Solder the resistor and LEDs in to the board and then connect all the powers and ground on the bottom of the board with solder.

-------------
Kevin Pierson

Posted By: fragydig529
Date Posted: March 18, 2009 at 12:36 PM

Cool, will do. Thanks =D
It might be a week or so before I actually get around to doing this.

But I'll try to post pictures when I do.