Liquid cooled 20k lumen stock fog light mod

[aeb28]

Hello all, I have been lurking around this forum on and off for the last couple years since I bought my 2004 SR5 4runner. I really love the car and I have finally found the time to finish some projects that have been in the works. I thought I would share one that I thought was pretty cool.

My goal was to fabricate a high output lighting system at a reasonable cost that does not change the appearance of the car. I like the look of solid rig, but a bone stock 4runner with only a huge light bar is not my personal taste. There are plenty of lighting options out there, but none that implement compact design with liquid cooling. In other words, a 200w LED system implies a large fixture, typically several feet in length. The primary hurdle in LED technology is thermal management. The large fixtures utilize passive air cooling with heat sinks that make up a majority of the fixture. I designed a system to overcome the issue of thermal management that can be retrofit into the stock fog light housing.

I removed the stock fog light collimator and lens. The stock optic seemed of poor quality (maybe just old) and appeared to have a beam angle of approximately 90-120 degrees. They had the stock halogen 55w bulb and really didn't do much for me in low vis conditions.

Each housing I re-fit with 100 watts of LEDs and upgraded the optic to a 60 degree beam angle. The manufacturer rates this at a total of 20,000 lumens. I won't get into the lux/lumens debate and "exactly how many lumens" is typically a pissing contest anyway. The fact is, they are quite bright and work amazing as fog lights.

The system draws about 20A, so I don't run them much with the car off. The other downside is that they are by no means street legal, nor would I want to use them on the street so long as there is oncoming traffic. Looking into them is like looking at a laser beam, it is very hard on the eyes. At best it would be a huge nuisance, at worst would cause an accident. On the other hand, I have some monster fog lights. The camera just doesn't do it justice.

Anyway, this was a fun project and I thought I would share. Let me know what you guys think.

 

[snivilous]

I like it! One question though, isn't it kinda overkill since I thought most modern LED systems had around a 90-95% efficiency and produced very little heat? I always assumed the heat sinks on LED bars were more for looks than anything, since aside from articles I have never felt an LED that was warm even a little. Regardless I like the stealthy setup!

 

[Minnesota Yota]

Pure mad scientist! does the switch say "want to drive with your brights on? OK" :lasercannon:

 

[aeb28]

I like it! One question though, isn't it kinda overkill since I thought most modern LED systems had around a 90-95% efficiency and produced very little heat? I always assumed the heat sinks on LED bars were more for looks than anything, since aside from articles I have never felt an LED that was warm even a little. Regardless I like the stealthy setup!

In reality they are about 6 times more efficient than incandescent and 15% more efficient than fluorescent. However LEDs emit about 30% of their energy as light and 70% as heat. They have made huge improvements in that within about a year they have gone from 65 lumens per watt to 90 lumens per watt. An average incandescent bulb is about 15-16 lumens per watt. Yes, FAR more efficient.

Those heat sinks are absolutely necessary. Thermal management is the key to the life of an LED. When a manufacturer advertises "70,000+ hours of life" that is under absolutely perfect circumstances with perfect thermal management. A one watt led is smaller than a millimeter, so about 70% of that watt is lost through heat and that heat must be dealt with. Temperature above 125 degrees C exponentially shorten the life of the LED.

edit: that is 125 degrees at the LED pn junction, not necessarily the temperature of the heat sink.

 

[m85476585]

Do you have any pics from the driver's seat?

If it throws too much light on the ground right in front of you, then it's no good for high speed because your eyes will focus on that area rather than the more important stuff in the distance.

 

[aeb28]

Do you have any pics from the driver's seat?

If it throws too much light on the ground right in front of you, then it's no good for high speed because your eyes will focus on that area rather than the more important stuff in the distance.

The stock fog light collimators have a diagonal reflector essentially cutting off the bottom half of the beam specifically for that purpose. Switching to a 60 degree beam angle with the modified setup was better than nothing, and is thus far adequate for about 45mph. I took a couple quick pictures while driving but they turned out blurry and aren't worth posting I have yet to test them on the interstate at high speed, but I am expecting to need further alterations to the reflector housing to compensate for washing out and nearsighting. There are still plenty of tweaks I still have to make, right now I am working on shock-proofing the driver housing so that I am not worried about anything shaking loose over time. My next goal will be to test them at higher speeds and see if further beam manipulation is necessary, my guess is that it will be for the reasons you have stated. That is also why the Ebay budget light bars receive a lot of criticism, they just flood the foreground out and aren't very functional at high speed.

 

[m85476585]

It's interesting that the stock fog lights cut off the bottom. I thought it was only the top to avoid blinding oncoming traffic somewhat. But I haven't really looked at them up close.

I designed a 1400 lumen LED light for mountain biking, and it was useless without a lens. I can't remember what angle I went with, but it was probably less than 20 degrees. For this application you probably want something wider horizontally, but you don't need much beam width in the vertical direction since they are mounted so low.

 

[aeb28]

On a closer look of the stock collimators, I see that lenses invert the beam pattern as you can see from the pictures. That reflector does in fact cut off the top half for to reduce oncoming glare, but creates a hot spot in front of the car worse than the setup I replaced it with. The difference is that a 55w halogen doesn't put out nearly the same amount of light, so it is not very noticeable.

Anyway for anyone who might be interested, here is the beam pattern with/without the collimator. The camera auto adjusts brightness, but the collimator loses A LOT of light. They look the same in each picture but in reality the collimator probably loses more than 50% of light emitted.

unrestricted 60 degree beam angle:

Light through stock collimator:

Here is a view from the rear where the bulb would go in, orange plastic and table for reference:

here it is from the front:

this is what the collimator assy inside the housing looks like: