LED gurus, your help is needed. How do I power LEDs from the batt w/o frying them?

[MetalMaxima 10+ year member]

Alright, so here's the dealio: I am going to be adding about 12 LEDs to my car interior, and if I try and tap one of the OEM sources, the LEDs simply don't get enough juice. So I tried hooking up 4 LEDs wired together on a single 18GA wire to the battery and one of the LEDs fizzled out. (Yes, they all have resistors). SOOO...it's obvious that I need to tap power from the battery. I aslo want to be able to wire the LEDs to a switch, 4 LED per switch. So, in short:

How do I tap the battery to power LEDs WITHOUT frying the LEDs?

Click to read more...

 

[flakko 5,000+ posts]

relay

 

[jacko 10+ year member]

are your LEDS 3v or 12v?

 

[MetalMaxima 10+ year member]

relay

How wold a relay help me out here? (I know how to use relays, do they regulate power?)

are your LEDS 3v or 12v?

3V.

 

[flakko 5,000+ posts]

well all i know about relays is that you can hook up a bunch of 12v stuff to 1 of them (LED's, Fans, amps even) using a single remote wire. I dont know much about 3v LED's tho

 

[jacko 10+ year member]

Relay won't help you here. Are you wiring them in parallel or series? If they are 3v, wire them all in a series(12v) and each one should get like 3.5v then when the car is on, or is this what you did already and the 3.5v's is frying them? Do you have the switch?

 

[MetalMaxima 10+ year member]

I didn't quite understand the relay thing either... Are you wiring them in parallel or series? If they are 3v, wire them all in a series(12v) and each one should get like 3.5v then when the car is on, or is this what you did already?

Sorta. I have each LED with a resistor attached and have a 12" set of wires for the pos and neg leads off of them. Then, I attached each of the led power leads onto another wire, and then attached to the battery. So basically, each wire leadin to the pos and neg of the battery has four leads attached to it.

 

[djman37 5,000+ posts]

what resistor?

 

[jacko 10+ year member]

so each wire is getting 12v until it hits the resistor? Are they your resistors? I'll try to find you a diagram quick and post it.

 

[djman37 5,000+ posts]

here's A calc that'll tell you which resistor to use. There are many more out there. req??

http://linear1.org/ckts/led.php

 

[jacko 10+ year member]

deleted

 

[MetalMaxima 10+ year member]

so each wire is getting 12v until it hits the resistor? Are they your resistors? I'll try to find you a diagram quick and post it.

Yep, THESE ARE THE RESISTORS I HAVE.

Thanks for the help, guys...this is driving me nutz!!!

 

[req 5,000+ posts]

here's A calc that'll tell you which resistor to use. There are many more out there. req??
http://linear1.org/ckts/led.php

lol.

heres what ya do.

when the car is on, they will get 3.5v each - the array should only pull like 80ma of current, so dont worry about it, but make sure your wire can supply that. if you wanna put them in your dome light, you can just hook directly to the +\- of that bulb jack. if you wanna do accent lighting, you can hook into the fusebox in the dash on a switched wire (key on = power, key off = no power) and you can put some kind of switch (potentimeter? sp? lol ) on the negative lead to power them on or off depending on your mood.

hope that clears it up. anything more than 4v for a few seconds could possibly kill them. that might be your problem.

you shouldnt need any resistors if you just wire them how i have shown above by the way.

 

[MetalMaxima 10+ year member]

AHHHHHH, SO THAT'S IT!!!!

Thanks, Req - I am going to try this during the weekend, I think you just saved my sanity. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[req 5,000+ posts]

good luck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif