LED wiring Question for Custom Headlights!!!

[Ram Z's SRT]

LED stats: 5mm blue led have forward voltage:3.1-3.6v and are 20mA

Here is a diagram of how I wired up my custom LED set up. I havent turned everything on to see how they look because I dont want to burn them out. Then I would have to start all over.
I need to know if the way these LEDs are wired would be ok and wont overload the actual led. I am planning on using either a 12V power source or a 9V power source.

 

[Ram Z's SRT]

Really no one knows... Bump!!!

 

[wesalbert]

I will take a look tonight

 

[Ram Z's SRT]

Thx man. I'm really excited to hook these up. I just need the go ahead.

 

[wesalbert]

I think your resistors are off. I thought they should be about 270. I checked on an online LED calculator and came up with 270.

Take a look here

http://led.linear1.org/led.wiz

See if you get the same answer as me. I have some LED's here I can try. I don't care if mine blow up.

 

[wesalbert]

If you bump the voltage from 12v to 14 (closer to what it will be at when the truck is running) then I get 390 ohm resistors

 

[Greg Good]

I would build a cheap circuit board that uses an LM317 (or similar) chip to regulate voltage. IIRC the LM317 has a 1.5 volt *headroom*, meaning the voltage drop through it will be 1.5 volts.

I think a good idea would be to run them in *strings*. 3 in series would be 10.8 volts. So, maybe you could plan on using 3 strings consisting of 3 emitters each.

Of course you could spend a little more money and buy a driver that regulates *current*, which is the way an LED should be run. In that case you could use one driver set at 160ma of current and run all of the emitters in one string. To run them all in series would require a *boost* type driver.

If you run them with resistors the current won't be steady as the voltage in the vehicles charging system rises and drops. The resistors that are correct at 12 volts won't be correct for 13.5 volts, and vice versa.

Here's a site that will help with the el cheapo home made circuit.

http://led.linear1.org/a-cheap-current-regulated-luxeon-star-driver-design/

 

[JTS VENOM PERFORMANCE]

I would build a cheap circuit board that uses an LM317 (or similar) chip to regulate voltage. IIRC the LM317 has a 1.5 volt *headroom*, meaning the voltage drop through it will be 1.5 volts.

I think a good idea would be to run them in *strings*. 3 in series would be 10.8 volts. So, maybe you could plan on using 3 strings consisting of 3 emitters each.

Of course you could spend a little more money and buy a driver that regulates *current*, which is the way an LED should be run. In that case you could use one driver set at 160ma of current and run all of the emitters in one string. To run them all in series would require a *boost* type driver.

If you run them with resistors the current won't be steady as the voltage in the vehicles charging system rises and drops. The resistors that are correct at 12 volts won't be correct for 13.5 volts, and vice versa.

Here's a site that will help with the el cheapo home made circuit.

http://led.linear1.org/a-cheap-current-regulated-luxeon-star-driver-design/

I would probably wire it up wrong, it would blow a headlight, shoot me across the room , knock over the engine hoist, it would fall on the hood of a truck, glance back off the truck, hit me in the head causing a 6 inch gash, have to run to the hospital, only to realize my health insurance ran out, sit there for 14 hours, bleed on the new shirt my wife just bought, only to get a doctor that thougt the area had allready been numbed after he started stiching, an finally leaving only to be handed a $15,000 bill for stiches, and on the way home find out my favorite waffle house was closed for health reason:argh::argh:

 

[Greg Good]

Nah, the worst that would happen is the LED's would let out *magic smoke* as they die.

I've killed more than my share of LED's and driver boards building flashlights. I had one light I was trying to build that had a short in the LED wiring. I fried three 25 dollar circuit boards before I figured out what was going on.

Another time was when I built a 3D Maglite with a Luminous SSR-50 LED. When I hit the switch the LED starting turing blue after about a second, and it let out its magic smoke and died before I could turn it off. :dontknow: A $50 mistake.


I wish I could tell the OP more about the 317 chip, but we don't use them in flashlights because they're too inefficient. We use chips that give our lights more runtime. The 317 is fine for automotive use though because there's plenty of electricity.

 

[wesalbert]

Another custom flashlight guy? Oh where is that thread about mine...

 

[JTS VENOM PERFORMANCE]

Another custom flashlight guy? Oh where is that thread about mine...

uh oh Greg.............I feel for ya LOLOOLOLOLOL

 

[Greg Good]

Another custom flashlight guy? Oh where is that thread about mine...

What kind if light is it?

Are you a member of candlepowerforums.com?

 

[Greg Good]

uh oh Greg.............I feel for ya LOLOOLOLOLOL

I love flashlights.

Put a nickle in me and I'll talk about them all day.

 

[JTS VENOM PERFORMANCE]

I love flashlights.

Put a nickle in me and I'll talk about them all day.

check out wally's thread, he has a ton!

http://www.vtcoa.com/forums/showthread.php?t=46556

 

[wesalbert]

Greg, did you sell lights over there? Yup. I am on there. Not so much these days.

 

[qdaddy]

hey, you copied me. haha Mine are LED halos as well.

 

[Greg Good]

Greg, did you sell lights over there? Yup. I am on there. Not so much these days.

No, I give mine away to friends usually. I've bought a LOT of parts from there. FiveMega, AW, TaskLED, Sandwich Shoppe, you name it. Even bought a McGizmo light from there, so I'm in the McGizmo club, ha ha. It's a nicely made light, and the reflectors designs are about as good as it gets.

I haven't been on there much lately either, too busy. It's my home page though. :rock:

 

[Greg Good]

check out wally's thread, he has a ton!

http://www.vtcoa.com/forums/showthread.php?t=46556

Oh wow....good thread. I might some pics of a few I've done. the ones my friends liek the most are the 3d Mags that run off alkalines. Most people don't want to fool with rechargeable batterries. I run 3 Cree XP-G emitters in series in direct drive (no electronics).

 

[Ram Z's SRT]

hey, you copied me. haha Mine are LED halos as well.

Hey man, I tried to look for the longest for someone that had that same set up. Where did you buy or get your kit from? Also I did want to see if I could do it myself as well... its an ego thing - always gotta be self sufficient.

 

[wesalbert]

Did you do the clear curtian rod thing to make the halos?