LED Headlights and Snow.

Proper aiming is as follows

Keith Tanner said:

84FSP said:

Keith Tanner said:

I thought I'd seen this in the CAN messages for the Tesla...

VCFRONT_headlampRightTemperature
VCFRONT_headlampLeftTemperature

I can't find one for headlight heaters, though - I can for the mirrors, seats, windshield and the little special windshield for the radar.

I wouldn't be surprised if the software is there for an option we didn't get on our pedestrian version.  I'd guess the X and S get them.  In the grand scheme I'm good with some compromises to keep the 3 available to humans like me.

I'm pretty sure my documentation is for all Teslas - most (all?) manufacturers have a common set of PIDs across their entire range. For example, this one includes "liftgate status".

Ah, I just found "headlight fan" so the concern is overheating, not cold weather in this case. But if you're trying to melt snow, maybe you don't turn the fan on :) After all, the car knows...

O_ 603 ID25BAPP_environment: 1 ChassisBus
 SG_ APP_environmentRainy : 0|1@1+ (1,0) [0|1] ""  Receiver
 SG_ APP_environmentSnowy : 1|1@1+ (1,0) [0|1] ""  Receiver

 

The headlight temperature monitor is to keep them from overheating.  They will reduce output if the drivers or diode substrate is too hot to avoid damage to the unit.  

I wonder if my Forte GT has heated headlights since it has LED lighting. I'm guessing no, because Kia. Strangely, the fog lights are projector halogens and not LED's. And they are the 1st OEM fog lights I've had on a car that actually do anything! That reminds me, I want to swap some yellow bulbs in those.

LED lights generate heat, they have heat sinks on the PCBs but yes its far less than the gas discharge high intensity lamps (HIDs) or halogens. This is an issue but its not what you think.  Some lamps have fans in it to keep it from overheating too, all lamps are vented to allow the release of moisture. The proximity of how close the LEDs are to the outer lens is a big factor on "heating up" the lens to melt the snow, this is why you see a lot of headlamp cleaners out there as required on vehicles in these situations because the lamp itself is inadequate to pass the requirements.

The OEMs mandate the lamps to be built to a specific validation test(s) and that test is made up from a lot of assumptions and general design assumptions so the design a test that is meant to encompass all but its a lamp in a box subjected to weather in a lab environment type approach and if it meets the requirements it passes. Depending how they dictate these cold weather tests is where this is the grey area. If they make the validation test easy or non replicable to the real world, then the lamp passes and life goes on. 

.02 from being in OEM lighting for years. 

wae said:

In reply to Keith Tanner :

"Headlight fan" sounds like one of those things you'd ask the newbie at the parts counter to go in the back and find.  It's next to the upper radiator hose for the 68 Beetle, you know!

you laugh but its true. 

this came out in 2015 for example and is the projector unit from the lexus RX models (2015+)  the fans do 2 things: regulate heatsink temperature because the LEDs will de-rate their power to limit output to save themselves from burning up and it also moves air around which can help with condensation on the inside which is an issue because of what we are talking about. I was apart of a potential patent where we basically make a power resistor in an area of the lamp that is funneled by the bezels/plastic internals to generate heat and send that heat like a chimney to the condensation problem areas, the other ideas I have seen is dessicants in the headlamp to absorb moisture but when the part is out of warranty and that thing is saturated you are gonna get a lot of fog on the inside. 

great junkyard find too because its high beam/low beam and has its own CPU for lighting and the fan is below the heat sink, 3 wires to hook up and can retrofit easily into other stuff :) 

I had these units crammed into my mazda6 wagon too but I am a lighting nerd and my wife is a lighting/optics engineer so yeah lol

fidelity101 (Forum Supporter) said:

LED lights generate heat, they have heat sinks on the PCBs but yes its far less than the gas discharge high intensity lamps (HIDs) or halogens. This is an issue but its not what you think.  Some lamps have fans in it to keep it from overheating too, all lamps are vented to allow the release of moisture. The proximity of how close the LEDs are to the outer lens is a big factor on "heating up" the lens to melt the snow, this is why you see a lot of headlamp cleaners out there as required on vehicles in these situations because the lamp itself is inadequate to pass the requirements.

 

The OEMs mandate the lamps to be built to a specific validation test(s) and that test is made up from a lot of assumptions and general design assumptions so the design a test that is meant to encompass all but its a lamp in a box subjected to weather in a lab environment type approach and if it meets the requirements it passes. Depending how they dictate these cold weather tests is where this is the grey area. If they make the validation test easy or non replicable to the real world, then the lamp passes and life goes on. 

 

.02 from being in OEM lighting for years. 

These are reflector designed lights, which in my understanding is much worse than a projector style for heating the lenses. Never had an issue with HID ones in the past.

In reply to java230 :

Led reflector or projector. Doesnt matter. HIDs are still halogen like as they put out a lot of heat for their wattage because The bulb is based on superheated gasses. GDHL is the trch acronym. Gas discharge headlamp it still gets hot like a bulb but Provides superior lumen/candela output because its high intensity In the sense that your mind cant comprehend what your eyes see because each color is registering off the charts so your mind assumes every color is white which is why you get such great visibility with them even to this day. But this enegery requires a Costly ballast and the led tech as a system is far more cost competitive for little performance loss.

Its wild stuff!

fidelity101 (Forum Supporter) said:

In reply to java230 :

Led reflector or projector. Doesnt matter. HIDs are still halogen like as they put out a lot of heat for their wattage because The bulb is based on superheated gasses. GDHL is the trch acronym. Gas discharge headlamp it still gets hot like a bulb but Provides superior lumen/candela output because its high intensity In the sense that your mind cant comprehend what your eyes see because each color is registering off the charts so your mind assumes every color is white which is why you get such great visibility with them even to this day. But this enegery requires a Costly ballast and the led tech as a system is far more cost competitive for little performance loss.

 

Its wild stuff!

Projector lights tend to throw their output through a smaller area of lens.  That means less area needs to be kept clear and the heat of the beam is more focused to do that (although it's not all that much heat with LEDs). 

In reply to fidelity101 (Forum Supporter) :

Interesting, the LED fogs however, get to 200+ degrees?  Emitters driven harder? Emitters are definitely closer to the lens, 1.5-2"or so. These are the fogs I run.

I've heard LED lights are generally too "reflective" in that they cause a lot of glare coming off road signs etc, is this the case for oem LEDs or just cheap aftermarket stuff ? Also what if you buff your headlights with some sort of oil based wax so ice doesn't want to adhere easily ?

In reply to fidelity101 (Forum Supporter) :

LEDs definitely generate a lot of heat, the problem being that it stays in the chip package (where it has to be conducted out through metal circuit boards, heat sinks, etc). While incandescent sources are less efficient at making visible light, they are at least nice enough to blast out the wasted energy as IR. IR still ends up getting reflected and going through the lens, melting snow / ice.  Additionally, since LEDs are more efficient at making visible light than incandescents, they use less input power, which leaves less heat energy available for melting things. For example, in householding lighting going from a halogen lamp to an LED lamp with the same number of lumens yields almost an order of magnitude reduction in electrical power draw. So I can see how you could conduct heat from the LEDs into the front of the housing for cooling, but it still seems that even with the best designs LEDs will always going to be at a disadvantage for clearing snow/ice compared to the old incandescents.

In reply to dannyp84 :

IMO thats a crappy optics design. I have had cheap, and very not cheap, and the difference is amazing.

In reply to MrRobogoat (Forum Supporter) :

spot on (light pun)!

In reply to rslifkin :

you can have projector LED lights as well, the optical system doesn't care about the light source. its just different but yeah thats true when focaled like that it is often near the lens and in a smaller area so it will stay more clear by comparison. In reply to java230 :

I believe so, I'd have to check what temperature they can get to but heat sinks will got hot to the touch, i can vouch for that. I'd say your measurement is pretty accurate, I remember 100c being a ballpark, so 212f is in your range there. 

In reply to dannyp84 :

thats more aftermarket because its cheap copys not based on physics or manufacturing capabilities, the knock off stuff looks the part but lacks the science behind it. its not more reflective, there are just more creative ways to get light on the road now with LEDs and reflector/projector design so light will go in other places than traditionally but if its not illegal brightness in those areas its not an issue. The sign is the reflective part a 100lumens from an LED vs 100lumens from a halogen lamp is still 100 lumens. 

In reply to java230 :

^^^ this the lights on power wagon are incredible and some lexus' out there are beyond bonkers, its light a full curtain of light emitting from the tip of the front bumper outward in all directions as a thin sheet. 

In reply to fidelity101 (Forum Supporter) :

So for my OE headlights, the heat sink is in the back some where, and the heat just isn't getting to the lens. 

The aftermarket fog lights, being smaller, perhaps they get the heat where its needed. Or the chips are just getting pushed harder? 

In reply to java230 :

the heat sink is on the LED for a low beam/high beam function like in the lexus image above, the heat sinks wont really help with de-fogging that much. without looking at the LED chip its hard to say but definitly the low beam/high beams have a few hundred gram heat sink hanging off of it.