LED bulbs in tailights

[Geof3]

Anybody running LED’s in their stock tailights? Any issues with heat or otherwise? I’m ditching my DEPO’s and going back to stock, but I’m thinking of replaced the stock bulbs with LED’s as the stock bulbs tend to get a bit hot. Let me know what you have!

[10/10ths]

....with putting LED bulbs in housings designed for incandescent bulbs, is that the reflectors will NOT give you a proper throw pattern and it ends up being much worse light than the stock bulbs.

The focal point of the parabolic reflector is in a different spot for incandescent and LED bulbs.

It's just science.

Not worth the money.

[Burg Boxster]

... even if you find LEDs a seller claims (even tries to show) the focal point will be consistent, you'll have heat issues to manage.

LED bulbs still generate heat and some A LOT depending on design! Even more will generated from the needed in-line resistors... for at least the indicator lights to prevent hyper flash all around. Each resistor needs to be securely mounted to metal and kept away from plastic as it can easily melt it. Bench test a 50W 6Ohm resistor w/ 2 LED bulb and tell me how long you can hold on? j/k please do NOT!

And depending on MY you may need to add them for brake / running lights too to avoid any CAN-BUS fault.

Good luck

[particlewave]

Yeah, I've tried several different iterations of my own making.
It's not worth the time or effort for the reasons already stated.

[KRAM36]

Originally Posted by 10/10ths

....with putting LED bulbs in housings designed for incandescent bulbs, is that the reflectors will NOT give you a proper throw pattern and it ends up being much worse light than the stock bulbs.

The focal point of the parabolic reflector is in a different spot for incandescent and LED bulbs.

It's just science.

Not worth the money.

Originally Posted by particlewave

Yeah, I've tried several different iterations of my own making.
It's not worth the time or effort for the reasons already stated.

Bingo!

I have experienced this myself with particlewave in person. I even left several LED bulbs with him to see what he could come up with.

What's wrong with your DEPO tail lights?

[Geof3]

No worries, and I pretty much thought that was the case. In terms of the Depos, really it’s more of a fit and finish thing. They just don’t match the body lines well IMO and I’ve tried several things to get them to fit better. They will be on the sales board soon!

[particlewave]

You can't beat stock. I used the VHT Nightshades red to convert a stock set of amber tail lights to all red. After having both the Depo and Dectane, these are definitely my favorite.

[Geof3]

Originally Posted by particlewave

You can't beat stock. I used the VHT Nightshades red to convert a stock set of amber tail lights to all red. After having both the Depo and Dectane, these are definitely my favorite.

Oh, I like that idea. I don’t have too much issue with the amber, but that looks nice!

[Javi Cooper]

Oh man. Not what I wanted to read when I searched for this Maybe things have changed in the couple of years since this thread was made?

I just replaced the 3rd brake light bulbs with LEDs and they looks fantastic (I have the aero kit 1 spoiler which uses the 996 3rd brake light). If there's a diffuser issue I can't see it, but then again I don't know what I'm looking for. I'd like to do the brake bulbs at the tail lights too. Would bulb or resistor heat still be an issue with the brake lights since they obviously won't be continuously switched on?

[PLP]

Originally Posted by Javi Cooper

Oh man. Not what I wanted to read when I searched for this Maybe things have changed in the couple of years since this thread was made?

Not much... the light pattern is still an issue.
However, as others I tried so many LED replacements and only two types gave me more luck.

https://ebay.us/wCGOQ0

Basically the design is the key.
Those two styles allow for good light focus and they mimic tungsten style light bulb filling the light assembly same way or very close to OEM.

[Zordrack]

With regard to heat I feel like I gotta make a semi snarky observation.

Yes LEDs get hot, but they do so significantly less so than halogens.
Set aside efficiency and the fact that the tungsten filament is literally so hot that it glows with black body radiation vs semi conductors that usually burn out at under 140C and just look at power consumption.

Standard halogen is 21w vs equivalent LED at 3w.

No matter how you slice it that means a lot less power in the form of heat being put into the housing.
That's just kinda physics 101. You don't get energy you never put into the system.

Not to say that you couldn't have crappy LEDs that have bad hotspots, but overall the heat load on the light will have to be significantly less.

Just saying

[Javi Cooper]

Thanks for the tips. What is it about the light pattern that makes the LEDs not suitable to use with a regular lens? Is it the brightness?

The delay between the 3rd light and stop lights coming on when the brakes are pressed is a little annoying, so I'm either going all LEDs or back to all incandescent bulbs if the LEDs aren't bright enough.

[PLP]

Originally Posted by Javi Cooper

Thanks for the tips. What is it about the light pattern that makes the LEDs not suitable to use with a regular lens? Is it the brightness?

No, not the brightness. The luminosity, aka light intensity.
A light may seem bright, but will not have enough power.

The problem here is the location of the light source, that is LED or tungsten wire.
Whenever you look on any light bulb replacement - the new one going in must have the light source in exactly same spot.
All the tiny reflectors, the ribs on the plastic (lenses) - they focus or scatter the light. It means that the turn signal or brake light will be intense when looking on it straight dead and to a certain angle.
If the light assembly is just filled with light, but does not have the "burning your eyes" feeling, it means that the replacement is not suitable or it was positioned incorrectly.

With enough numbers of LED chips one can achieve the same overall light intensity (number of lumen, for example 21 W 1156 light bulb is about 400 lm. One 5050 LED chip is roughly 25 lm, so you need almost 20 of them.

The problem becomes how to concentrate the light from 20 chips... especially that each of them can only light up about 120 degrees (+/- 60 from the center).

Therefore, the 2 styles I listed above somehow go around it.
I tried them in different housings and all of them had good results. Same or even better intensity than stock.
They cost much more, though.

Whatever you do - test it side by side. Do NOT use a camera as it will trick you. Better, do one side and look on both sides at the same time. If it does not look as intense as stock - do not do it.

[Zordrack]

The light emitting part of an LED is neither the same shape nor in the same location as the filament in a regular halogen bulb.

And since angle of departure is the same as angle of incidence the light will not be focused and directed correctly in a reflector made for halogens.

Personally I don't worry about that unless it's for headlights (high/low/fog) where beam pattern is really crucial.

But don't expect to get "correct" beam pattern out of a reflector light made for halogen with LEDs in it.