LED’s
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=10766
Printed Date: May 15, 2024 at 6:55 AM
Topic: LED’s
Posted By: pipes
Subject: LED’s
Date Posted: March 11, 2003 at 7:48 PM
What do I need to wire LED's up to be powered by 12volts. Say I want 5 or so LED's in my car to come on when a switch is pushed.
Replies:
Posted By: dsn2gr8
Date Posted: March 11, 2003 at 9:47 PM
you should use a relay to power up all of those LED's connection of relay: pin 86 12VDC pin 85 ground (switch should be installed here) pin 30 12VDC (fused of course!) pin 87 going to LED's pin 87a not used hope this answers your question.
Posted By: pipes
Date Posted: March 11, 2003 at 10:27 PM
Yes and no. Can I wire LEDs in without resistors or do I need special components.
Posted By: sammy004
Date Posted: March 11, 2003 at 10:37 PM
you need resistors if they are 3 volt or less around 500 ohm
Posted By: bdl666
Date Posted: March 12, 2003 at 10:07 AM
You don't need a relay all you need is a resistor for each led.Contact ssullivan777 here on this forum he can help you out.
Posted By: auex
Date Posted: March 12, 2003 at 4:02 PM
If you are running +12V then I would recommend that you use 12V leds.
-------------
Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.
I've been sick lately, sorry I won't be on much.
Posted By: sammy004
Date Posted: March 12, 2003 at 5:50 PM
you dont have to use 12V LED's they are expensive. I would just get a 2-3v LED and a 500-600 ohm resistor and hook it up to 12V Cheaper
Posted By: pipes
Date Posted: March 12, 2003 at 7:08 PM
I'm wiring them under my dash for lighting instead of neons. So how many can I connect in series, I've read that you can connect like 4 3volt and not need any resistors, is this true?
Posted By: sammy004
Date Posted: March 12, 2003 at 7:17 PM
Varad makes led lightrods why don't you just buy those
Posted By: 1998chevy1500
Date Posted: March 12, 2003 at 9:57 PM
try this website https://linear1.org/ckts/led.php they have a resistor calculator to find out what size resistor to use
-------------
Posted By: Dose3782
Date Posted: March 12, 2003 at 10:24 PM
I would think even wired in series the first LED would blow if you are using 2-3v LEDs. I mean good ol' K mans law says series is additive, so 4 3v LEDs in series should = 12v's, but the first LED would see 12v's, and the second would see 9v's, so on so on untill 0v's at the ground. Basically a voltage ladder using LEDs as the resistors. So the first LED would blow so it would'nt work. As Sammy was saying, use a 500ohm resistor on the power wire side for each LED. You can play with the resistor size to make them brighter or dimmer, sorry but I don't have my paperwork in front of me for the min/max size of resistors for the LEDs so they don't blow up or don't light up. Hope that helps! Good Luck!
-Kyle
-------------
Posted By: Vincent454
Date Posted: March 12, 2003 at 11:21 PM
Just use ohms law for your resistors. You are running off of 13-14 volts. Check and see how many amps your resistors require. Take 14 volts divided by...20-30 milliamps (.02-.03 amps). This will be the value of the resistor you need.
Posted By: pipes
Date Posted: March 13, 2003 at 5:14 PM
I have 11 LEDs I need to wire and figured that wiring them in parallel is best and that way I only need a 44ohm resistor. No to find some cheap blue LEDs.
Posted By: MielGibson
Date Posted: March 13, 2003 at 6:26 PM
You have to limit the current going through the LEDs.
For that you need to know 2 of the LEDs parameters: Operating voltage and current.
So, to wire up 3 LEDs at 1.5 Volts(operating voltage) drawing 20 milliamps (operating current) from 14 volts, you would go like this:
14 - 3(1.5v)/20Ma
14 - 4.5 / .02
475 Ohms
I would use a larger resistor value (510 ohms) to avoid burning the LEDs prematurely.
Posted By: pipes
Date Posted: March 14, 2003 at 7:14 PM
However in parallel your equation would be wrong, it would need to be 14 - 3(1.5)/60ma. I did some research and found this site for calculating such things . https://linear1.org/ckts/led.php
Posted By: MielGibson
Date Posted: March 15, 2003 at 7:55 AM
Sorry, I forgot to mention that that equation is for LEDs in series, and yes, it should be 60Ma.
|