Laxplaya11385

I heard that sometimes LEDs can burn/melt the wires that they're connected to. Can anyone that has installed LEDs in the dome/as reverse lights, shed some light on this topic? Any problems thus far? Particularly the guys or gals that have had them installed for 8+ months. Thanks.

frenchnew

The only way that this can might happen is that if one of the wires gets shorted and even then the fuse will blow.

LED uses less current then a conventional filament type bulb.

Also, LED do not run hot as opposed to the filament type bulb which will burn your finger.

Here are some quick comparison between LED Lights and some of the Light bulb on our TL.

Light Bulb # 2825 used in the Ceiling Lights (4), Trunk Light, Vanity Light. This bulb is rated at 5 Watts, 12 Volts which is a current draw of 0.416 Amp at 12 Volts and a little more at 13.2 to 13.8 Volts.

The common LED Replacement for these are using between 0.024 & 0.034 Amps which is less then 10% of the current draw of the regular filament lights.

So, you could use up to 17 of those LED Bulbs (Up to 9 LEDs per Bulb) together before you draw the same current as one 2825 Light bulb

Have a look at the specifiactions for those LED Bulbs at http://www.superbrightleds.com/1157.htm

I have been a Certified Electronic Technician since 1976 and never seen a LED damage the wiring.

Best regards


frenchnew

2004TL6SP

Thanks for a concise and very informative post.

need4spd

Frenchnew,

While I agree with your thoughts in theory, misapplication of the LEDs without a current limiting resistor could create an over current situation of the wires, as overdriving the rated voltage of the LED causes an exponential rise in drive current (eventually the LED will burn out due to too much current, but until that happens, they could draw a substantial amount of current.

The basic problem with LEDs is that they are NOT current limiting on their own like an incandescent lamp (incandescent lamps are basically light emitting resistors, so they self limit the current draw).

LEDs are light emitting diodes, and at the rated voltage and if all the stars and universe are aligned, will draw rated current at that rated voltage, but once the voltage supplied to them goes above their rating, the current they allow to flow rises exponentially until the junction temperature of the LED increases to a point where the bond opens, burning out the LED.

The lesson here is that you should not use LEDs unless you know what you are doing, all they need is an in line resistor to limit the current.

For example:

14.4Volt source (typical operating voltage of the car when it is on and the alternator is working)

Blue or White LEDS = approx 4V rated voltage (note, red, yellow and orange are 2V each, so this calculation does not apply to them)

Place 4 blue or white LED's in series, you get 12V, the resistor will take up the excess voltage (14.4V - 12V = 2.4V)

Resistor= 2.4v/0.02A (0.02A is the typical current rating of most LEDs) = 120 Ohm resistor needed

Then you need to figure out the power rating of the resistor = 2.4V x 0.02A = 0.05W, so a standard 1/4 Watt resistor would work fine (120 Ohm, 1/4W resistor) connected in series with the three series connected LEDs.

Conversely, if only using one blue LED, then you need to drop 10.4Volts / 0.02A = 520 Ohm resistor (rated 1/2 Watt, do not use 1/4 W as it will get too hot, as this calculation is 0.2W, at at near full rating, resistors get very hot).

Anyway, you get the point, don’t just wire up your own LEDs unless you know what you are doing, and hope the kits or pre-made items are properly designed and tested.

frenchnew

First and foremost I was trying to convey that people should not take for godspell everything they hear.

I am talking about properly made replacement bulb like in the link that I supplied and those are already made to work on an 12V automotive electrical system.

If you had bothered to look at the link, you would have save your valuable time learning that such premade LED Replacement bulbs do exist and from reliable suppliers.

I was not talking about making his own replacement bulb at it is beyond people lacking proper electronic knowledge.

As for Ohms Law, I learned that 33 years ago.

Laxplaya11385

damn..you guys both know your shit!

Hahah...Ohm's law. I learned that last semester in physics. Damn....i got a lot of restudying to do for my MCATS!

Thanks for all the advice though.

need4spd

Laxplaya11385 - Glad to help

frenchnew, sorry to go off on a tangent, but I was trying to explain that people need to buy stuff that is properly designed. I also wanted to inform those who DIY that they need to be careful, as these are not the same as light bulbs.

Over the last few years, I have seen plenty trying to DIY LEDs into areas of the TL, so I wanted to cover them also, and as Lexplaya had a very general question, I did not want to assume anything.

I did follow your link by the way, and in general was familure with what you were implying.

No flames please.

frenchnew

No Problems and please accept my apologies If I offended you or others.

As for doing your own led conversion bulb, like you said, is not for the newbies.

I personnally plan to do some led bulb conversion myself when I have the time as my schedule is too rocky these days (16 to 18 hrs /day). The only one completed was the security LED that was changed from a red to a Blue LED.

Best regards

frenchnew

need4spd

No problem.

I had wanted to add blue LEDs in the door handles (inside, shinning down from top), which would be an easy tie in to the illuminated window switches. This would help to see the handles at night, and especially helpful in the ebony interior. But I only had my car for about 4 short months. Dam Acura.

Top line cars such as the 7 series has this, along with other LED light pipe along the interior of the doors and mood lighting effects (such as lighting of the interior "C" pillars with a splash of LED light)

In some mini vans in Asia, I have seen LED mood lighting from the tops of the interior "B" pillars also.

It is easy if you know what you are doing.

Happy moding