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LED Headlights - good, bad, etc?


How many of you all have LED front headlights? I just bought s vehicle with them (2017 Mazda CX-5). While I think they’re good, they look and perform (in my opinion) as well to HID. It’s actually hard to tell the difference between them.

So, I wanted to ask if yoI’ve had any issues with them? I’ve been reading some info on LED failures, and the expensive rate it is to replace them. I always thought they would outlive the vehicle for the most part.

Anyway, just curious what your thoughts on LED’s are as a whole.


My son just bought a branny new CX-5. And brand new Honda Odyssey.

I don’t really like the harshness of the light they emit, but they’re here to stay. They’re part of the equation to meet elevated mileage mandates. In short, I prefer incandescent lamps (quartz-halogen) but hey, it is what it is, so I simply accept them.

The CX-5 overall looks like a nice vehicle. My son likes his. He tried the competition and says the CX-5 is a lot more fun to drive. I don’t know the official color designation, but his is what I’d call blood red.

Anyway, that’s all I know about the LED arrays. And about CX-5s. :grin:

Here’s a link to Insurance Institute for Highway Safety articles about headlights. The gist of what I’ve read from them and from Consumer Reports is that the effectiveness of the headlights isn’t much related to the technology used to turn the electricity into light, but more to the design of the reflector, housing, lens, etc.

I’ve had LED headlights for a year and a half and haven’t had any issues with them. I did have an HID light replaced under warranty though. I’ve converted a lot of my house lights, garage, and outside lights to LED over the past few years and have yet to have one fail.

On household LEDs I might suggest a conspiracy theory, backed by my experience: the very first CFLs I bought were working until recently, while newer (and cheaper) ones were failing almost as often as incandescent ones… so likely the first generation of LEDs will last long, but once they go on the cheap side, they will start failing long before emitters fade. Likely it will be the same story as CFLs: as manufacturers will cheap out on electronic components like capacitors, etc…, LED assemblies will not last anywhere close to their emitters rated lifetime.

For vehicle LEDs, especially OEM ones, I would expect them to last the lifetime of the car as emitters life ratings are very high and car makers in general do not put crap into electronic components.

@Jman136 You worry too much , relax .

Those chicklet parts you mention, they are already the lowest cost parts available on the planet. Where LEDs can go wrong is on thermal management. Insufficient heat sinking of the die due to cheap boards or poor soldering process is more likely scenario…

The public (and even industry) has been brainwashed on LED longevity. Like anything, derating based on application is EVERYTHING. LEDs typically advertised for 70k hours is based on absolute best case usage. Erode margins by driving them harder or not dissipating heat properly and the lifetime goes down- way down.

Not LED car related but we have 9 recessed flood lamps in our kitchen and I should have made a note of when we put the LED floods in because they have been in there a long time as compared to the incandescent lights . Also the same goes for the 5 LED lite curio cabinets we have .

I have seen a bunch of defective LED household lights already. The failures were all flickering or blinking, which means a failure in the electronics, not the LED itself. So I agree, it’s poor design or cheap components.

Personally, I would put a higher likelihood on a failing connection for those symptoms over a failed/failing component. Until you get to root cause, it’s nothing but conjecture :wink:

I’m too curious, I almost always take stuff like this apart to figure out what went wrong. Sometimes I even fix it and put it back in service. You can learn a lot by looking at failures. I would say the vast majority of what I find is related to poor process control or outright disregard for long term effects. Prime example is no clean flux residue…

I love LED headlights like those on the CX-5 that turn into the corners. Adaptive lighting is not just cool, but IIHS gives automakers higher scores for various features. The real question should be “do they light the road ahead any better.” That is not clear yet. In testing by IIHS in its indoor facility with the most advanced instrumentation available, the LEDs results are hit and miss so far. More here at BestRide on that if interested. I don’t have any news on them being unreliable.

I agree, it is all about guessing game until you have a root cause determined.
Equipment I was repairing mostly had problems either with soldering or cheap Chinese capacitors which would literally crack open from the internal pressure.

Sort of. Different methods of turning electricity into light produce different spectral curves, and our eyes respond differently… and not all the same.

In addition, various methods of producing light convert different portions of the energy consumed into light and heat. LEDs convert a larger portion of the energy consumed into light, a much lower portion into heat, which is why they’re more energy efficient. Incandescent lamps convert a relatively large portion of the energy consumed into heat, less into light. The goal being light and not heat, incandescent lamps are relatively inefficient.

Reflectors, lenses, etc. then manage the light beam, and they definitely are important, but the light source itself really is different.

@the_same_mountainbike - Mazda’s red car color is called “Soul Red Metallic”. My 2014 Mazda 6 came in that color and, four years later, she still sparkles in the sunlight. I still get compliments when I pull into the gas station to fill up.

Guessing is half the fun!
Curious about cracking… What type of caps? Ceramic, film, tantalum, electrolytic? Radial, axial or surface mount?

Electrolytic, mostly of barrel form with two leads on one side.
At some point, flickering or not working LCD monitor or TV would be more than 50% chances to find a blown electrolytic capacitor, which is a trivial repair.
Here is a good sample picture:

The one on the left is clearly gone, the one on the right is a border case.
Here is even better one:

LED headlights have a downside, blinding other drivers, and could cause a collision.

“[LED headlights] may be creating a dangerous distraction for other drivers. “It’s almost like looking into the sun”. Drivers of oncoming vehicles said they’re literally blinding. “The bright illumination can be disabling,”

I would say that OEM LED lights are way lesser concern than retrofits people mindlessly put into their headlights not designed for LEDs or HIDs, resulting in a lot of glare into the eyes of other drivers.

This is what frustrates me a lot with USA drivers, as in Europe all these “retrofitters” would be carefully caught/fined to the extent where this bright idea would not be so popular as it is now in US.

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OK, thanks for the pics and clarification.

In the bottom picture, you’re looking at a 2000-5000 hour cap. It’s actually a decent version of electrolytic cap and longer design life than your garden variety (assuming design constraints are met). So in that case, it’s not a question of substituting in a lesser cap to save money.

Electrolytics have two main issues related to lifetime- one, they cannot tolerate much voltage ripple over time. Seems like an ironic issue since that is one of their primary goals. But excessive ripple will kill them prematurely. Two, they dry out over time and fail.

Most design efforts concerned with maximizing MTTF will disallow the use of electrolytics. Not long ago, we did a power supply design with a mandated minimum 700k hour MTTF and there was an exclusion for electrolytics in the design.

There have been huge advances in this area with manufacturers like Nichicon having extremely long life electrolytics now. But you have to design for them and keep the power supply ripple as low as possible to maximize lifetime.

To be fair, you’re not going to see anything like those caps in an LED lamp, let alone one that goes into a traditional light socket. Those will most definitely use solid dielectric or monolythic caps since the assembly will be encapsulated. And those caps do not have similar limitations like those above.

Wow, that’s an interesting perspective I never considered, but hey… I’m a software guy primarily… who likes to get a soldering iron or a wrench into hands sometimes :slight_smile: