Safe aftermarket LED headlight bulb info, finds and discussion

[redmoe]

The crazy thing with LEDs is how inefficient they are in optical output. I read it’s something like 60-95% of the input energy is lost to heat. It’s not as obvious since it is not the light emitter giving off the heat (like in an incandescent bulb) it is the base semiconductor. Hence the need for enhanced cooling. They still use less total input power per lumen than incandescent (about 80% less) it’s just surprising how inefficient they are in and of themselves.

 

[redmoe]

Just got the temp readings:

https://youtu.be/kDqhBepQq7g

Quick summary:
Headlight housing/bay ~150F
LED bulb heat sink ~174F
Driver ~180F

Looks like 24 deg delta between the bay and LED components. The temps did not change much from first popping the cover to the 3 plus min that I measured for. Should be fine to leave the components covered in the housing.

Quick note: The typical material used for the headlight housing is good to 300+ F and the wire insulation at least 210+F (for the cheap stuff).

 

[Business6]

Just got the temp readings:

https://youtu.be/kDqhBepQq7g

Quick summary:
Headlight housing/bay ~150F
LED bulb heat sink ~174F
Driver ~180F

Looks like 24 deg delta between the bay and LED components. The temps did not change much from first popping the cover to the 3 plus min that I measured for. Should be fine to leave the components covered in the housing.

Quick note: The typical material used for the headlight housing is good to 300+ F and the wire insulation at least 210+F (for the cheap stuff).

Fine work! Thanks for the info!

 

[danbfree]

If its any consolation.....I have been running XENONDEPOT H11 LEDs and they utilize a aluminum ribbon and I have tucked them into the housing and closed them up....No issues to be reported or failure and its been over a year on their Gen 2 Extreme H11 LED bulbs.

Oh yeah, you are supposed to run a pass-through rear cover for those, at like $7 a set it's cheap insurance for them to run cool.... I am considering that style too, the good ones start at like $80, and I just saw those Xenon Depot for about $100.

 

[danbfree]

Just got the temp readings:

https://youtu.be/kDqhBepQq7g

Quick summary:
Headlight housing/bay ~150F
LED bulb heat sink ~174F
Driver ~180F

Looks like 24 deg delta between the bay and LED components. The temps did not change much from first popping the cover to the 3 plus min that I measured for. Should be fine to leave the components covered in the housing.

Quick note: The typical material used for the headlight housing is good to 300+ F and the wire insulation at least 210+F (for the cheap stuff).

That's way too hot for them not to dim, we're not talking about the material melting, LED brightness/power draw drops dramatically at temps past 50 centigrade/122 Fahrenheit according to this chart I found real quick, there is other sources out there too.

https://www.mouser.com/applications/lighting-derating/

 

[redmoe]

That's way too hot for them not to dim, we're not talking about the material melting, LED brightness/power draw drops dramatically at temps past 50 centigrade/122 Fahrenheit according to this chart I found real quick, there is other sources out there too.

https://www.mouser.com/applications/lighting-derating/

This in not the correct plot to evaluate temp vs light output. First thing to consider is the local temp at ~65C as the measured in the engine bay. This sets on lowest possible temperature. The bulb heat sink temp was measured at ~79C.

I did not find a data sheet for the Exact LED chip in the Hikari but here are two examples of Phillips LEDs. You can see that the relative light output vs pad temperature there is a very small change between 65 and 80C. Also since the measurement was taken at several points in time with the back cover off the last temp taken of the bulb heat sink was fairly representative of the nominal temp on the system in the open air environment of the engine bay. Essentially leaving the cap off did little to reduce this temperature.

 

[danbfree]

This in not the correct plot to evaluate temp vs light output. First this to consider the local temp is ~65C as the measured in the engine bay. This sets on lowest possible temperature. The bulb heat sink temp was measured at ~79C.

I did not find a data sheet for the Exact LED chip in the Hikari but here are two examples of Phillips LEDs:

All figures aside, look at any listing for LED bulbs and 80c is the rated highest temp, you need better cooling and you can do that with $7 pass through covers. But seriously, thank you for bothering to take temp readings, it really helps show how we are really running at the bleeding edge of the rated operating temps and a whole other thing to discuss solutions for.

Sent from my LG-H932 using Tapatalk

 

[redmoe]

They are referencing the environmental temp and not the bulb heat sink temp. Without external air ducting 65C is the best it will get which is in spec.

Keep in mind Environmental temp(working temp) is highly dependent on the cooling design. The higher quality systems will have better materials and bearings (if they have fans) yielding higher working temps or at the very least improved temperature stability.

 

[danbfree]

They are referencing the environmental temp and not the bulb heat sink temp. Without external air ducting 65C is the best it will get which is in spec.

Keep in mind Environmental temp(working temp) is highly dependent on the cooling design. The higher quality systems will have better materials and bearings (if they have fans) yielding higher working temps or at the very least improved temperature stability.

Well said, I fully agree in principal, 65 degrees is definitely just fine but 79 is really pushing the edge of safe operating temps so I still feel we should be taking steps to ensure proper cooling. That means running pass through rear covers, as to me $7 is not worth leaving the heatsinks, either a fan base or copper braids, crammed into the housing and sealed. I have heard of a number of failures due to that and I'm not going to take that risk so I'll continue to recommend pass through rear covers. I'll try some here and let you guys know how they work.

 

[redmoe]

Increasing the thermal mass and surface area is your best bet to reduce the temperature in the bulb. The challenge is obtaining a bond with sufficient thermal transfer and doing this without negatively impacting the existing thermal management system.

It’s hard to say whether the closed assembly is better/worse than the open back without CFD modeling both systems. The closed system may have benefits by not loosing the potential cooling effects of the outside air cooling the lense thus having a larger cooling effect on the small contained volume in the headlight assembly.

I’m curious how you are going to measure your results of using the different caps and added heat sinking material? I think the most insightful testing would be to measure the lumen output and temperatures in the various configurations. Without a measurement of the optical output we really don’t know how the LED is changing with temperature.

 

[danbfree]

So I decided to put my money where my mouth was and finally ordered some rear covers.... I went with the top rated ones that are $10 on Amazon and more of a universal type where you trim away the excess as it's "accordion" style. I'll post some pics when I install this weekend.

https://smile.amazon.com/dp/B076Q9D52Z/

 

[danbfree]

Increasing the thermal mass and surface area is your best bet to reduce the temperature in the bulb. The challenge is obtaining a bond with sufficient thermal transfer and doing this without negatively impacting the existing thermal management system.

It’s hard to say whether the closed assembly is better/worse than the open back without CFD modeling both systems. The closed system may have benefits by not loosing the potential cooling effects of the outside air cooling the lense thus having a larger cooling effect on the small contained volume in the headlight assembly.

I’m curious how you are going to measure your results of using the different caps and added heat sinking material? I think the most insightful testing would be to measure the lumen output and temperatures in the various configurations. Without a measurement of the optical output we really don’t know how the LED is changing with temperature.

You've provided what are, to me, some pretty scary temp readings, I'm doing this for longevity mainly. To me it's simply the right thing to do is keep them in the right temp range with a $10 investment. This keeps the fan heatsink sealed away from inside the housing, I will even experiment to see if I can loop/drape the drive modules to hang outside as well.

 

[ROCKYFiestta]

I am going to try the cree chipped hikari the cheaper ones for my brights and see how they are/differ from the hikari led with phillips chips. ill post a pic up once they are installed.
https://sellercentral.amazon.com/nm...JPkBVHg&n=1&u=aHR0cHM6Ly9hbXpuLnRvLzJNV3A3Vko

 

[ROCKYFiestta]

can post up a pic on the fitment of the covers i was about to put some holes in the stockers and call it a day but i saw you linked the nice ones just wondering if you got around to it.

 

[danbfree]

can post up a pic on the fitment of the covers i was about to put some holes in the stockers and call it a day but i saw you linked the nice ones just wondering if you got around to it.

My oEdRo low beams are too long to fit entirely in the housing and at 32mm BARELY clear the sides, even slightly touch, so can't install. So I just ordered the MAXGTRS from early in this thread, they are 30mm wide so can use the covers with those... now have to wait a good 2+ weeks, but less than $29 with free shipping and look just about as good as the Hikari.

 

[FLORIDAST]

Are these bulbs still recommended? Looking for some better output for night driving.

https://www.amazon.com/Headlight-Co...079KB7QX3/ref=cm_cr_arp_d_product_top?ie=UTF8

 

[danbfree]

Are these bulbs still recommended? Looking for some better output for night driving.

https://www.amazon.com/Headlight-Co...079KB7QX3/ref=cm_cr_arp_d_product_top?ie=UTF8

Of course the Amazon guide to fitting isn't always right but it does say they will fit.... they very well may be short enough to clear the back housing, if you have Prime they would be easy to return if they don't fit, otherwise they DO look worthy of trying out.

 

[alexrex20]

my AliExpress LED headlamps just got to Chicago. can't wait to try them out

 

[TyphoonFiST]

They're here....both sets....now just have to install them!

Sent from my SM-N950U1 using Tapatalk

 

[FLORIDAST]

Of course the Amazon guide to fitting isn't always right but it does say they will fit.... they very well may be short enough to clear the back housing, if you have Prime they would be easy to return if they don't fit, otherwise they DO look worthy of trying out.

I bought them and the accordian style dust covers (the ones with the hole in the back) and they should be here tomorrow. I hope they work out!