Wiring LED's

[GeoffSFAs10]

ok..so heres the scoop. I love lights and having them on my truck. So i was bored today and farting around with stuff i could do to my tmaxx and i decided i want to wire up some LED's on it. Heres is the plan for their local. In the air damn of the S10 body ..one on each side, fog light resemblance, and then i have the old light bar off this truck and i cut the faces off the lights and the dome is hollow, , so i have 5 off road light shaped domes on the roof of the truck..i want an LED is each one. So i would have 7 total facing forward. i should prolley run the lower two lights on their own battery and the 5 on the roof on their own. SO my question is how do i wire these guys up? And where is a good place to get soem LED's....i cant find any around here really. Any help is welcome. thanks guys. ANd by the why..when i get this all done i will do a write up on the build and such.

 

[JasonInAugusta]

LEDs need a current limiting resistor connected in series with them.

To figure out the ohmic value of resistor you'll need, there's an online calculator you can use:

http://www.bit-tech.net/article/68/

When you buy LEDs keep in mind that the higher the mcd numbers, the brighter the LED will be.

Here's a link to some LEDS...

http://www.superbrightleds.com

Take a gander at the LEDs on the superbright link, plug the values into the calculator, and you'll know what size resistor you'll need for each LED.

If you want to use a couple as functioning headlights and fog lights, pay attention to the spatial distribution info. Also look at the continious forward current numbers. Those should be plugged into the above calculator along with whatever voltage you plan to run.

 

[GeoffSFAs10]

ok cool. thanks for the website too. Its got alot of good stuff.

 

[metomwhou]

So, I searched and still feel stupid. Why is this crap so hard, am I over thinking it?

First of all, I used this calculator http://led.linear1.org/led.wiz
I plan to buy these LED's http://www.ledshoppe.com/Product/led/LE1002.htm and http://www.ledshoppe.com/Product/led/LE4002.htm
And I plan to use a single 9v battery.

Here's what I want to do:

I want to run two head lights and be able to turn them on and off.
I want to run 5 overhead/spot lights and be able to them on and off.
I want to run the parking lights/brake lights and side marker lights all together and turn them on and off.

Thats a total of 17 lights. The calculator says to use a 270ohm resistor for each LED or 100ohm per each pair.
So, for the headlights thats one 100ohm resistor or two 270ohm resistors.
For the spotlights, thats two 100ohm and 1 270ohm or 5 270ohm resistors
For the rest of the lights(10), that would be 5 100ohm resistors/one per pair.

.....Still with me?

Can I wire up the headlights as a "circuit"(proper term?) with an on/off switch, wire the spotlights as a "circuit" with its own on/off, and finally wire the rest of lights up as a "circuit" with an on/off AND connect all three to the same power source?

Also, if somebody smart wants to just tell me step by step what to do, that would be cool too

 

[goo]

You will need to make sure your battery does not over or under power your LED's. pushing more than the rated voltage will burn them out, too little and they will not light up.

(check post #3 on this thread, simple illustration included)
http://www.rccrawler.com/forum/showthread.php?t=92181

To answer your question, yes you could break up the the sets and give them their own on/off switch and wire them all to the same power source.

I threw together a very ugly wiring setup, but i hope it helps you out with your question. The battery is in the middle, there are 3 switches (headlight, spotlight, otherlights). Notice where there are 2 LED's in series, you will need a 100 ohm resistor, with a single LED you will need a 220 ohm resistor (all according to that LED calculator). I apologize it is ugly...but i'm not an electrical engineer, i just toy with this stuff.

Anyway, good luck with figuring it out! :shock: (oh man...now that i look at it...it is really ugly!) Let me know if you need any help with it.

 

[metomwhou]

Thanks Goo. Should I try to wire them in parallel or series?

 

[goo]

it really depends on what you want the wiring to end up like. If you want a single set of wires for each LED, then wire them all in parallel with resistors.

Wire all on/off switches in parallel to the power source

(parallel) Then have a wire coming from the switch for each LED (with resistor) you plan to hook up to it. This way, each LED has a set of wires which makes it easier to move them around and position them.

(series) Or (headlights for example) have one wire going from the switch to the first LED, from there going to the second LED, then to the resistor and back to negative on the power source.

In that crap diagram i did, the switches are parallel to the power supply, then from there it is pretty much in series. Except for the spot lights and running lights. Because there are 5 spot lights there are 2 sets of 2 LED's in series, and 1 LED to complete the bar (wired parallel to the switch).

(according to that LED array wizard site)
1 LED with a 9v power source will need a 220 ohm resistor
2 LED's with a 9v power source will need a 100 ohm resistor

 

[metomwhou]

How long do you think that 9v will last with all the lights burning? I'm still confused over series and parallel but I'll figure that out I guess! I was also thinking of the three circuits as seperate units, each connected to the power supply so I'm not sure how the on/offs would work wired together.

 

[Dodgefan01]

Wiring in series should keep the battery life a little longer.

Also wiring in series, if one burns out in that circuit, all other will turn off as well until you fix the "break" in the circuit.

Just my .02

 

[El Gooch]

This is a well informed thread guys. Thanks for all of your info. This is going to help me as well.

The Gooch8)

 

[mato_h]

i think that wiring them in parallel is better because if one light goes out they don't all stop