# Car LED Clusters

Discussion in 'The Projects Forum' started by Chris @ EA, Sep 7, 2010.

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1. ### Chris @ EA Thread Starter New Member

Sep 7, 2010
3
0
Dear all Projects

I am having trouble trying to work this out, i have tryed time and time agin on a program called "Circut Wizard". I do no a general jist of electronics however this one may seam simple to you guys but im stumped.

I have a customer with a VW golf who would like to replicate the outside light clusters on the inside clusters but also the fog.

I would be using 20 bi-colour LEDs (red and yellow) each side. Listed below are are the voltages that i've got.

Idicator 3v
Side 3v
Stop 12/13
Fog 12/13

To get the side, stop and fog working on the red LED i can figure out but i think that i would need to relay the reds of so the yellows can be seen. Ther diagram that i have worked out keeps blowing the LEDs due to the reverse voltage.

Thank you for yout time.

Chris

2. ### BMorse AAC Fanatic!

Sep 26, 2009
2,675
241
Why don't you post what circuit you are working with, that way we can have a better understanding on what you have already accomplished..... from what it sounds like, you may not have the proper current limiting resistors in place, and also, you will most likely have to run the LED's through a voltage regulator, since automobile voltages can get up to 14.5 volts.....

But of course, this is a thread that threads (no pun intended) on the brink of being closed since this is one of those topics that is not allowed on here (since you are modifying an automobiles lights, this could lead to safety issues)......

B. Morse

3. ### Dyslexicbloke Well-Known Member

Sep 4, 2010
546
34
A couple of things to get you started ..

1. LED's need a constant current drive.
OK that might simply be a resistor but you shouldnt be thinking in terms of voltage particulaly if you are trying to drive the things close to their maximum output.

For example if you had a white LED with a forward voltage drop of 2V and a constant current requirement of 500mA ( A 1W led) to connect it to a 12v system you would need to drop 10V (system - Vf) at 500mA which requires a 20Ω.
There two problems with this ....
first your resistor needs to disipate 2.5W
second when the system is at 14.2v (Charging) your lead would be forced to accept a little over 600mA becaust the lede still drops 2V so the resistor now has 12.2 volts acros it.
(Hey I get you will have more than 1 in series which helps but just wanted to give you a primer on the thought process)

2. If you put a relay anywhere near an LED, or anything else sensative for that matter put a back EMF diode on the coil.

3. Multy colour / bicolour LED's are just several LED's in one package. they may or my not have aditional control circuitry included. The also usuly have a combined total power disipation for the package so if more than 1 elliment is on you may need to derate accordingly.

Al

Sep 4, 2010
546
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Al

5. ### marshallf3 Well-Known Member

Jul 26, 2010
2,358
203
It's not just safety issues, state laws govern quite a few things that have to do with the color, intensity and height of the "brightest spot" whem it comes to lighting. It can also be hard to decode all these laws and limitations since tey're often in several sections of the motor vehicle codes.

We've got our share of strange ones around here and while 95% of the officers may not notice or not care if something isn't really obviously out of line but others are just looking for a reason to pull you over.

We had one law on the books that was so stupid I kept getting pulled over for simply having the FACTORY driving lamps on. It got so bad I had to print out the code and carry a tape measure with me to prove to some of them that I wasn't violating the code as written. They finally reworded the law to allow a bit more leeway but not all the officers get the word.

6. ### t06afre AAC Fanatic!

May 11, 2009
5,939
1,227
The problems then it comes to replacing light bulbs with LEDs. Is that LEDs do have much more narrow way of spreading the light. This may not be so important for the driver, but indeed for other road-user, cyclists and pedestrians. As they may not see your light signals. If your thread get closed you will still be wellcome back any time, as this action is not the same as banning

7. ### Chris @ EA Thread Starter New Member

Sep 7, 2010
3
0
Ah, sorry guys. It always sounds correct in my head but when i come to typing or writing it out i may forget a few things.

I wont be changing the factory LED/Light clusters at all so they will stay the same and working as normal. On the Mk5 VW Golf you have the main lights on the body of the car and just some reflective clusters on the boot lid. The ones on the boot lid are the ones that im trying to convert.

The link below is of a youtube clip that i have been given.

Sep 7, 2010
3
0
9. ### SgtWookie Expert

Jul 17, 2007
22,202
1,793
Sorry, but we have had to discontinue discussions on exterior automotive lighting.

It has become illegal to modify automotive exterior lighting in Canada, where this Board has it's servers located. Therefore, to stay within the letter of Canadian law, we can no longer entertain such discussions.

10. ### Dyslexicbloke Well-Known Member

Sep 4, 2010
546
34
As long as the thread is up, I will be happy to help if I can.

20 LED's / side OK but What are they? (Part number or spec)
Do you want Turn + Side
or
Turn + Stop + Side?
I know mods like this, aditional lights, are permitted in the UK (I live here) but
Do you have anything to measure the light output to ensure you are within permissable limmits? too bright a tail lamp wouldnt be good.

I am asuming the voltages you mentioned at the top are to achieve diferent brightness (see my previous comments) even so I am still confused since stop fog and indicator would normally require a 21W bulb whilst tail would be 4W right?

Why the low indicator level?
Al

11. ### Dyslexicbloke Well-Known Member

Sep 4, 2010
546
34
Sorry posted at the same time ......
if it not permitted here then I won't offer ferther help.
Al

12. ### Dyslexicbloke Well-Known Member

Sep 4, 2010
546
34
Sorry my post colided with yours .....
offer of help duly withdrawn
Al