Automotive Lighting 101

Introduction

Today we have a bewildering array of different automotive lighting types available from both Original Equipment Manufacturers (OEMs) as well as the aftermarket. Although OEM lighting is generally higher quality, aftermarket lighting has a huge range of both quality and performance. Add to that the internet and the ability to spread information (or false information) at the speed of light (no pun intended) and one has a recipe for disaster.

So, crashnburn80 and I got together and decided to take a swing at educating our friends here at Tacoma World about some of the basics of automotive lighting. We decided not to cover everything to start with – just the basics. Our intent is also not to get too deep or too scientific about the subject, but still to have a solid scientific footing for everything that we say.

And so, without further delay, let’s dive into the subject of automotive lighting.

Basic Types of Lights on a Vehicle

There are many different lights on the average motor vehicle. Some are designed to help us see where we are going. (Like headlights.) Others are designed to help other motorists see us or warn them. (Brake lights for instance.) Others are designed to provide information to both the driver and passengers. (“Idiot lights” on the dash for instance.)

Virtually all automotive lighting is regulated by a number of government standards. These standards helped drive consistency across manufacturers and in many cases dramatically improve the safety and quality of automotive lighting. Although some might argue that government standards are preventing certain new lighting technologies from getting to market, they have also prevented some pretty obnoxious (and pathetic) aftermarket product from getting out too. But the question of whether or not a given lighting product meets a particular standard may be a huge issue.

For the purposes of this post, we will deal mostly with automotive headlights and / or lighting products which are designed to allow us to see further down the road. This is arguably the most challenging type of lighting to design too. As you’ll see later on, it’s pretty easy to design and build “brighter” headlights. The challenge is to do that in such a manner as to conform to government standards and so as not to blind oncoming drivers. (That’s the big trick BTW.) Oddly enough, warning lights on emergency vehicles are almost exactly the opposite challenge. They’re not designed so much as to allow one to see further down the road as they are to grab the attention of oncoming drivers. So many of the traits that make poor automotive headlights actually make great warning lights.

Lighting is a System, not just Bulbs

When most people ask about “upgrading” their lights, they generally seem to refer to “brighter bulbs.” While in some cases a “brighter” bulb could upgrade the lighting on a given vehicle, one has to remember that an automotive headlight is made of a number of inter-related and co-dependent parts and systems. Today, many “upgraded” parts are available. The trick is to understand what the separate parts are, what they do and how they all work together. Knowing this is important so as not to screw up a well-balanced system. Let’s look at the major separate parts of an automotive headlight.

Light Source: Something has to glow and give off excess light. After all, that’s the basis of a headlight. Today, we generally have three different types of light sources for motor vehicles. There’s the standard incandescent (halogen) bulb, High Intensity Discharge (HID) bulbs and Light Emitting Diodes (LEDs) which are actually a semiconductor “chip.” All three have their advantages and disadvantages and none is a clear overall winner. More on this in the next section.

Lens: A lens has always been a convenient way of bending light in ways to make it do something we need it to do. Most early automotive lenses were simply flat pieces of glass with “flutes” molded into them. These flutes were lines in the glass with different shapes and thicknesses that re-directed light from the filament or bulb to places where we wanted it and not to places we didn’t want it. Many current halogen lighting systems use a simple clear lens and the job of re-directing light falls to the reflector. But projector lighting systems use a fairly complex lens and related optics to more precisely direct light from the light source.

Reflector: Many light sources (halogen & HID for instance) create an “orb” of light. This can be great in some situations, but we generally don’t want / need a full 360-degree orb. In an automotive headlight, we generally want all of that light to be projected outward and away from the vehicle, but also to specific areas ahead. So how does one get it all going in the same / desired direction? We re-direct a good deal of it by reflecting it off of a shiny (reflective) surface. By shaping this surface carefully, we can actually re-direct it in a number of different directions. Many older lights used a simple smooth reflector and depended on the lens to fine tune the re-directed light. More recently though, lenses went smooth and reflectors got complicated. Just two different ways of doing the same thing.

Housing: We now have a light source, a lens and a reflector. But what holds everything together? That would be the housing. And since the relationship and positioning of the previously mentioned components seems to get more and more critical, housings have gotten more and more complex recently too. In fact, on many new vehicles with LED headlights, one cannot simply replace a burned-out bulb – because there is no bulb. One must replace the entire housing - which contains all of the above-mentioned components. You’d better be sitting down when you hear the price of one of those bad boys though!

Wiring: Most illumination sources require some amount of electrical power in order to glow. And that power needs to be switched on an off as desired by the vehicle and driver. That job falls to the wiring – which is a means of conducting and re-directing the available electrical power in a vehicle. Like all of the previously mentioned components, the wiring needs to be designed in concert with the other components so as to safely carry the loads imposed upon it. Wiring also seems to be the most forgotten / misunderstood component of an automotive headlight system. Lots of folks increase (sometimes dramatically) the load on their wiring by adding “brighter” (higher wattage) bulbs, then wonder why their wiring melted or burned up.

Illumination / Light Sources

We brushed on the subject of illumination sources above, but since they’re such a significant chatter source of information and misinformation, we wanted to deal with them separately and specifically.

In the good old days, there was basically only one illumination source for motor vehicles – incandescent bulbs. These came in many sizes, styles and even voltages, but pretty much all of them within a given type were the same. Said another way, there were no significant performance advantages or design differences between them.

In the past, Europe had much less restrictive lighting standards than the United States and some fairly innovative products began to emerge from the other side of the pond. One of these was “capsule” style bulbs in separate housings. (The US had sealed beams.) By separating the illumination source from the housings, reflectors and lenses, this design opened up a whole new world of replacement parts that included some pretty decent lighting upgrades.

Generally speaking, we have three main categories of illumination sources available to us today:

Halogen: Halogens are the standard lighting technology in most vehicles, typically associated with a slightly yellow temperature color in the low-mid 3000k range. Their warm color temperature has advantages for better visibility in rain/snow/fog/wet roads. Halogens work by heating a tungsten filament in a halogen gas capsule to generate a near instantaneous omni-directional light source. The technology is simple and inexpensive but has a relatively short life span compared to other lighting technologies. The filament will thin over time and eventually will burn out. Halogens are very inefficient compared to other technologies giving off much of their energy as heat, this inefficacy does offer one advantage in automotive lighting as the bulbs will defrost their lighting lenses in cold weather.

High Intensity Discharge (HID): HIDs were the next generation lighting technology after halogen. They offer significant improvements in output, efficiency and bulb life but with added system dependencies. OEM HIDs are typically in the low-mid 4000k color temperature range, which is optimal for night vision, and produce more output than any other mainstream automotive lighting technology.

Often referred to as ‘Xenon’, HIDs work by creating an electrical arc across a gap inside a noble gas filled capsule producing an omni-directional light source. In order to create this arc, the voltage needs to be stepped up significantly – generally 20x or greater over the stock 12v system - requiring a ballast. The ballasts responsible for the voltage increase give off Electromagnetic Interference, which can pose electrical issues on a vehicle, most common is static on the radio or CB, but on ever increasing vehicle electrical complexity it can be difficult to say what the EMI may affect. A ballast should contain shielding to protect the vehicle from EMI, but many aftermarket systems lack adequate shielding. Unlike halogens or LEDs, HIDs are not an instant on technology. HIDs require a warm up period of many seconds, so while brighter, this makes them very poor candidates for high beam, as one would be left momentarily without light when switching to high beam waiting for the bulbs to warm up. While HIDs run cooler than halogen, part of their light spectrum output is UV light which will defrost icing on the lens surface in cold weather.

Light Emitting Diode (LED): LEDs are the latest mainstream automotive lighting technology. They offer greater efficiency and life than their HID counterparts. LEDs are a solid-state semiconductor chip that emits directional light when charged. Their solid-state nature makes them extremely durable, most OEM LEDs are considered a 'lifetime' part and are not designed to be independently replaceable. Their compact size makes the lens design smaller than other technologies. LEDs light up faster than HID or halogens, giving advantages to warning light systems like brake lights or emergency lights. LED bulbs run cool, which can cause issues for defrosting a headlight lens in cold weather which is why OEM LED headlights use lens defrosters. However, LEDs do generate a non-trivial amount of heat on the backside of the bulb at the driver which can pose challenges for cooling. Low quality aftermarket LEDs utilize cooling fans as a solution to prevent the LEDs from overheating.

Automotive LEDs produce light in higher color temperatures at 5000k-6500k, which is less ideal for night vision and causes light refraction in rain/snow/fog/wet roads leading to reduced visibility.

Why brighter light is not always the same as more usable light

Almost everyone is looking for brighter headlights – or maybe more correctly – more usable light on the ground in front of their vehicle. And that’s an important clarification because brighter headlights don’t always give you more usable light on the ground. Yes, you read that right. But why?

First, let’s be clear in that more light in the wrong places is generally wasted light. So, if the “brighter” lights you just spent your hard-earned money on just splash light all over the place, you may not end up with more light where you want / need it. We’ll deal with that subject more in the section on Beam Patterns.

Second, if some of that additional light from your “brighter” headlights happens to be aimed at oncoming drivers, you’re going to blind them and they’ll think you have your high beams on. That’s generally why people flash their high beams at you – because you’re blinding them. I think we can all agree that this is a bad thing. This issue is generally called “glare” and we’ll deal with that one in a minute too.

Finally, if your “brighter” headlights are not aimed properly – even if they have the correct beam pattern – they will anger oncoming drivers because you’re (once again) blinding them. Generally speaking, the brighter a given light is, the more critical beam pattern and aim becomes.

So how do we actually get more usable light on the ground? That’s a tricky combination of a brighter illumination source, a more tightly controlled beam pattern and correct aiming. Get any one of those three wrong, and although you may have more light on the ground, you’ll be too busy reacting to everybody flashing you to notice it.

Sealed Beams, Capsules, Projectors, etc.

Without going all the way back to using candles and lanterns to light the way in front of automobiles, probably the earliest form of standardized headlights most TW members will remember is something called Sealed Beams. These were standard sized sealed units consisting of a lens, reflector, illumination source and housing. The advantages they had over previous systems were standard sizes and shapes, reduced water intrusion and dramatically improved forward lighting. Sealed beams were the standard of the world – or at least North America - for many, many years.

On the other side of the pond however, they looked at the same automotive lighting problems and came up with a different solution. They let auto manufacturers design pretty much whatever size and shape housing, lens and reflector system they wanted. Into these systems fit standardized Halogen bulbs with O-ring seals (sometimes called capsules) to prevent water intrusion. The big kicker was that whatever design you came up with, it needed to meet government standards for how much and where the light went. Generally speaking, these systems were light years (no pun intended) ahead of what we had in the US – and people noticed. Eventually, these designs made their way across the Atlantic and now lighting systems around the world are much more similar and standardized – not to mention much better.

Another development allowed by going to separate / capsule style bulbs was the projector headlight. Remember those noisy slide projectors the neighbors used to bore you to tears with by showing their last twelve vacations after dinner? Remember how bright and focused the beam of light coming out of that device was? Eventually somebody stayed awake for long enough in a slide show to wonder if this same technology could be used for better automotive lighting.

The result was what some argue is still the biggest leap forward in automotive headlights – the projector beam. By using pretty much the exact same lens and shielding technology from the humble slide projector, engineers were able to use a brighter illumination source – which normally would lead to more glare – and focus it much better. This led to “more usable light on the ground without blinding oncoming drivers” – which as we all know is the Holy Grail of lighting. The addition of High Intensity Discharge (HID) bulbs – which was simply not possible without projector technology – made this type of system even more effective and attractive.

Glare

How do you like it when an oncoming vehicle has (or seems to have) their high beams on? Distracting isn’t it? And it’s also a safety issue since looking into bright lights can partially blind you. And even if “that idiot” does switch back to low beams, your vision is still negatively affected until your eyes can re-adjust. And your eyes don’t care if it’s somebody who just forgot to shut off their high beams or some idiot running LED / HID bulbs in a housing designed for Halogen bulbs. The result is the same.

The result we’re talking about is called glare. It’s unsafe, it’s undesirable and it should be avoided at all costs. But what causes it? The main cause of glare is too much light that happens to be aimed right into the eyes of oncoming drivers and there are many causes – most of which can be avoided.

One common way that manufacturers use to avoid glare is to cover the tip of a halogen bulb with a high temperature coating. These “glare caps” eliminate much of the undirected light from escaping from a light housing. Another popular way of accomplishing the same effect is a fixed glare cap built into the housing itself. The bulb is then mounted behind / underneath this cap. Since the cap is finished with a reflective coating, light is re-directed back into the reflector where it now goes where the designer needs it to go for maximum benefit.

On many vehicles producing excessive glare, a little detective work will lead you to discover that the owner pulled the OEM halogen bulbs and replaced them with either HID or LED bulbs that have no built-in glare reduction device. Excessive glare is one of the biggest complaints about aftermarket headlight bulbs and has led several states to enact laws prohibiting their use.

Basic Beam Patterns

We’d mentioned that the brighter the light, the more we need to control it in order to avoid blinding oncoming drivers. What many folks don’t know is that there are a number of “standard” beam patterns available – especially in aftermarket auxiliary lighting. And OEM lighting has a number of government standards regulating how much light needs to go where. Why not one beam pattern that makes everybody happy? Because there’s no such thing.

Headlights: By definition, these are almost always a compromise. They need to light an area far enough in front (and out to the sides) of the vehicle so as to avoid the ability to “over-drive” the headlights. That means you need to be able to see far enough out in front of you so that you have a chance to change direction or speed if something shows up in your way. It also means you need to be able to light up roadside (and overhead) signs, all while not bothering oncoming drivers. It’s a lot harder to do than it sounds.

Fog Beams: Quite possibly the most misunderstood beam pattern out there – probably because so many vehicles come with “fog lights” that aren’t really fog lights at all. A true fog beam is a very well defined flat, horizontal pattern that generally spreads across 135 degrees or more across the front of a vehicle. Of particular interest is the fact that it’s not designed to reach very far down the road. It is designed to shine under fog (or rain and snow) in front of the vehicle so as to avoid reflection and thus glare for the driver. (That’s why a true fog beam needs to be mounted low on the front of a vehicle.) It’s also designed to illuminate out to the sides of a vehicle so one can keep an eye on the shoulder of the road during inclement weather and thus stay on the road. A properly designed, installed and aimed fog beam will generally not blind oncoming drivers.

Cornering Beams: Closely related to fog beams are what some manufacturers call cornering beams. This beam pattern is designed to help drivers see “around the corner” somewhat by using a very wide-angle beam pattern, but does not have the clean cut off of a fog beam pattern.

Driving Beams: In many ways, a driving beam is the opposite of a fog beam. It’s not designed to illuminate out to the sides or under fog. It is designed to illuminate a path much further down the road – generally much further and in a narrower beam pattern than high beams. Even properly designed, installed and aimed driving beams cannot be used when there is any oncoming traffic due to excessive glare as they are related to a high beam pattern.

Pencil Beams: This type of beam pattern is exactly what the name implies – a very narrow (pencil) beam of light that reaches far down the road, farther than any other beam pattern, but not out to the sides at all. This beam pattern is designed to help one see very long distances down the road in front of you. But due to the extremely narrow beam pattern, this type of light is generally paired with other beam patterns to fill in the other areas in front of the vehicle. Generally used only on off-road / high performance vehicles and aiming is extremely critical (and difficult) with this type of beam pattern.

Flood Beams: Pretty much the exact opposite of a pencil beam, a flood beam pattern is also designed to do exactly what the name implies – flood a limited area with light. Since the power of the bulbs used in most of the above-mentioned beam patterns are pretty much the same, one can imagine that a flood beam takes the same amount of light as a pencil beam, but spreads it around in a much more widely distributed area. Construction and farm equipment generally use lots of flood beam pattern lights.

Aiming

Proper aiming of your headlights (or any auxiliary lighting) is more critical than ever with the availability of higher powered lighting. In the old days of sealed beam headlights, aiming was not as critical because – quite honestly – they all sucked. All one had was a “blob” of light that was neither well defined nor very bright. Unless the aim was way off and / or you were using your high beams, almost nobody would notice. With the significantly more powerful lighting that is available today, proper aiming is critical to both performance (putting usable light on the ground) and not pissing off oncoming drivers with glare.

What’s the best way to aim your headlights? Rather that attempting to re-write the book, look here: https://www.danielsternlighting.com/tech/aim/aim.html

Another thing that (negatively) affects lighting performance is how far above ground level your headlights are. Generally speaking, if you go much above stock height (as in lifted trucks), you’re going to run into problems with both putting usable light on the ground, reach and blinding oncoming drivers. You’ll hear folks say “If you lift your truck, just aim your headlights down a bit.” Sure, this may (somewhat) reduce the tendency to blind oncoming drivers, but what do you think this is going to do for the reach of your headlights because you’re effectively aiming them into the ground? There’s no simple fix to this except to understand the situation and not make it any worse.

I should note that with some lighting (LED or HID bulbs slapped into housings designed for Halogens for instance), not matter how you try to aim them, you’re still going to either blind oncoming drivers or not have enough light where you want it – or maybe even both. That’s because you don’t have an aiming problem, you have a glare problem. No amount of aiming is going to fix that.

Another interesting “feature” (or defect) of many cheap aftermarket bulbs is related to filament (or light source) placement. Name brand and OEM bulbs have very tight controls over filament placement because moving the illumination source even a little bit within a bulb effectively changes the aiming of the light. (That’s why that cheap set of Chinese “blue” bulbs you just put in screwed up your headlight aim even though you never touched the adjusters.)

Cutoff – What the heck is it?

You may have heard or seen the term “cutoff” used in reference to automotive headlights. And I should note that the term didn’t even exist a number of years ago – particularly when it came to old sealed beams headlights. But as we’ve said, automotive lighting has gotten a lot better in the last few years and one of the big advances was better beam definition. Said another way, more light where it’s needed and less where it’s not.

Think of it this way. For your headlights, do you want light on the ground, or light up in the night sky? Obviously the most useful light is on the ground – generally out in front of you. So, manufacturers have migrated to beam patterns that project outward and downward – where you need it most. What this looks like when you pull up to a garage door or wall is a very well defined flat, horizontal line with very little light above what is called the cutoff line and most of the light below the cutoff line. Makes sense, right?

Things get a little more interesting when we flip things around and experience the cutoff from the view of an oncoming driver though. The intent of the cutoff is to prevent excess light from the projecting vehicle from making it directly into the eyes of oncoming drivers. But an interesting thing can happen with the projecting vehicle hits a bump in the road. What the oncoming driver will experience looks for all the world like somebody just flashed their high beams at them when indeed nothing of the sort happened. What they really experienced was the cutoff (temporarily) moving up far enough to expose them to the full output of the oncoming vehicle’s lights.

Interesting trivia: This is actually the same principle used in “rotator style” warning lights. While it may look like the light is “flashing,” it’s actually just the cutoff line going around in horizontal circles.

OEM vs CAPA vs Aftermarket Housings

Your vehicle came from the factory with a set of Original Equipment Manufacturer (OEM) headlights. They were designed to meet both internal (manufacturer) standards as well as all applicable government standards. Generally speaking, they’re pretty darn good.

If you happen to crash your vehicle, or need to replace your headlights, the only choice you used to have was OEM parts – which if you hadn’t noticed are pretty expensive. OEMs made a small fortune off of replacement parts and your insurance company noticed this. They decided that although some aftermarket parts were not equivalent to OEM, some were. And generally speaking, they were a lot less expensive. So, they created what was called the Certified Automotive Parts Association to review and certify only the best aftermarket parts as meeting all critical OEM specifications for performance, fit, finish, longevity etc.

Theoretically, a CAPA certified aftermarket headlight should fit, perform and last as well as a more expensive OEM part. But we’ve seen (and experienced) some CAPA certified parts that aren’t quite up to the levels of performance of OEM parts. I think it’s very safe to say that an OEM headlight will outperform a CAPA certified unit and a CAPA certified headlight will out-perform one without a CAPA certification.

Color Temperature

Color temperature is a way to measure the color of light in terms of degrees Kelvin (K), where lower values are warm (yellow) and higher values are cool (blue). The range for these in automotive applications may be from 2500k for yellow fogs to 7000k+ for misguided aftermarket headlights. The important thing to understand is the ideal temperature range for your intended purpose and the capabilities of your lighting technology platform in relation to your desired color temperature. The ideal headlight color temperature for night vision is going to be around the low 4000k range. High color temperature ranges make vision at night more difficult with less contrast using blue light. Higher color temperatures have shorter wave lengths which leads to more refraction causing vision issues on wet surfaces or driving in rain/snow/fog.

Halogen bulbs have a natural output in the low-mid 3000k range. Halogens will not produce light in the 4000k range without filtering out some of the warmer colors to allow cooler colors to dictate the color temperature, which means removing usable light and reducing bulb output. This is done with a blue coating on the bulb. Example: Sylvania Silverstars. While the light is whiter thanks to the light filter, it is also lower in lumen output. Many people associate the whiter light with higher output and confuse the fact that the bulb is actually producing less light. The farther from the natural color temperature of the halogen bulb you try to achieve, the darker the coating (filter) must be applied to the bulb, further reducing output. If you wanted to improve the output of a light bulb, would you put window tint on the bulb? Of course not. The best performing halogens are going to be those with an uncoated (unfiltered) bulb.

When you turn up the wattage on a halogen bulb, the bulb burns at a higher color temperature and in the case of a respectable headlight, may be in the mid-high 3000k color temp range. Unfortunately, brands like PIAA leverage this to claim "60/55w = 110/100w", meaning they coat the bulbs heavier to make light output whiter, so the light output color appears similar to a high wattage halogen to justify the claim. The coated "60/55w = 110/100w" bulbs will produce less light than a stock wattage halogen because they have applied window tint to the bulbs.

HIDs do not need light reducing filters to alter light color temperature. You can often select OEM supplier HID bulbs (Osram/Philips) in ideal light color temperature in the low 4000k color spectrum. This will typically out-produce the lumen output of all other bulb color options. Unlike halogens where higher power is whiter (cooler), turning up the power on an HID reduces color temperature (warmer). Stepping up the ballast from a 35w unit to a 55w unit, the HID bulbs lumen output will be increased while color temperature will be decreased. That’s generally a win-win situation if aiming and beam pattern is correct.

Auxiliary / “Off Road” Lights

There are many different auxiliary lighting options and many different mounting locations to choose from, including roof light bars, lower light bars, ditch lights, pod lights etc. It is important to consider how you intend to use your lights and what you want out to get out of them to make informed choices to match your expectations. There is no one solution fits all.

Roof (LED) Light Bar: The main advantage of roof mounted LED bars is sheer size and elevation. You can put a lot of LEDs in a roof bar providing significant light output with better top down elevation. These of course cannot be run on the street. But less obvious is the roof lightbar will create massive glare on the hood. Having significant near field illumination from hood glare will reduce your eyes ability to see distance at night. So, while it creates a lot more light, it also reduces your ability to see distance in the dark. There are steps you can take to reduce the hood glare such as mounting a glare guard “shelf” below the light bar which reduces light to the hood. This does reduce glare, but also creates a small sail for highway driving increasing wind noise and decreasing highway MPG. Another option is to mount the light bar further back on top of the cab rather than the typical right over the windshield mount. This is more effective than the glare guard, but also reduces the down angle effectiveness of the light, which will push the effective distance out further from the truck.

Bumper Mount LED Light Bar: A light bar forward of the hood line provides zero body glare, so you get significantly better distance illumination visibility. However, light sources lower to the ground like the popular lower bumper valence bars provide less depth perception at distance than those elevated higher. Ideally if looking for a distance light source, it should be mounted near the height of the headlights forward of the hood-line. There are several grills that will mount a light bar in this location. No matter where they are mounted, light bars should not be run on the street with oncoming traffic.

Ditch Light Pods: Ditch lights mount at the base of the A-pillar and should face outward to the ditch to give a much wider lighting field than possible by forward facing lights. These are great awareness lights for off road or situational proximity awareness driving. They are not acceptable for oncoming traffic street use. Some point these lights forward and create significant hood glare as discussed earlier, reducing distance vision. Recent new versions of ditch lights will allow the lights to face forward with some side firing LEDs to illuminate the ditch. This provides forward facing lighting but still causes hood glare. It would be better to just rotate pods to the ditch to avoid the hood glare and get the desired proximity illumination.

LED Pods: LED pods are extremely popular to mount anywhere possible. It is important to understand the beam pattern of the pod vs where you are mounting it and what you want to achieve. Several companies promote putting 'spot' pods in the OEM fog location for example. Spots have no cut offs and very isolated illumination pattern, which is poor for the fog location. It is better to understand how you intend to use your pods and the beam pattern you require before selecting a pod and mount point. The only legal pattern for oncoming traffic is SAE Fog, but there are many differing pod beam patterns and mounting locations available. Everything from stock fog, to lower valence, to upper grill, ditch lights, roof rack, bed lights and more.

LED “Raw Lumen” vs “Actual Lumen” Specs

Lumens are a measurement of light output from a light source used to compare output. It is important to understand the difference between actual lumens and raw lumens when comparing ratings though. Halogen and HID light sources specify actual output, meaning the lumen rating is what is actually produced by the bulb. LEDs specify 'raw' ratings, which is the theoretical maximum of each LED chip multiplied by the number of chips. This theoretical rating is far greater than the actual output rating. Reputable LED brands like JW Speaker specify a 40% loss from raw rating to actual rating, meaning a 1000 lumen raw rating equates to a 600 lumen actual rating, but this varies by LED chip and manufacture.

The important take away here is to understand what lumen rating you are looking at – especially for comparison purposes and that all manufactures may not be equal.

Conclusion

We hope that this somewhat lengthy – but not as lengthy as it could have been – post on automotive lighting will help you understand automotive lighting a bit better. And hopefully this better understanding will help you make better / more informed choices when it comes to lighting on your vehicles.

 

Awesome article!! I’ll admit, I didn’t read it all yet, but there is a lot of good info there that many people don’t seem to undersand.

One suggestion - pictures of different lighting options and beam patterns would be a nice addition if you have the time to add them.

Very good work though!

 

Thanks! We're working on adding pictures - including exactly what you asked for. Just got to find the time to do it!

 

@Too Stroked Nice work for putting this all together.

 

This is more than I'd ever have learned about lights, and I didn't know how valuable it would be to have all this information - thank you!

 

I couldn't have done it without the help of the "lighting master" here! Thanks for all of your help!

 

... Nice n informative.

 

Bump

 

Awesome information

 

Outstanding and informative

 

Super cool. I will refer back to this as needed, as I mod my truck and need to learn more. thank you.

 

Thanks so much for your contributions to this forum. It's refreshing to read informed, scientific discussions versus speculative gibberish so common in automotive (and other) groups.

 

Great job on this write up @Too Stroked and @crashnburn80! This is a super informative post, and I think it deserves to be stickied. I am actually in the process of working on an article for our blog that covers similar information - but now I feel like I don't even need to as you all have it covered!

 

Just needs a mod like @tcBob to sticky.

For your blog, I would highly suggest still posting it, I’d even suggest posting a link here in this thread for others. The more information and education available for people, the better. The KC site is a good source of balanced lighting information.

 

I can't tell you guys (and girls) how honored I am to have this thread promoted to "sticky status." Crashnburn80 and I worked pretty hard to put this thing together and all of that work is now worth it. I do promise to maintain the thread as needed and will try to add pictures at some time in the future.

 

Too Stroked. I'm "from the town of Bedrock" and new here and just got a new Truck 18 TRD Off Road after recently trading in my 03 Tacoma. Way too much going on with these trucks now technology wise!

All I would like is for some folks who simply changed their bulbs with some after market bulb for high, low, and fogs to chime in.

I'm always pressed for time it seems, so not a professor on any topics, and glanced at my manual last night.......... H9 and H11 for high and low beam, and it mentioned TWO choices for Fogs,,, "regular vs. wide angle" don't remember the numbers and I'm at work on lunch.

I"m 64 and would be interested if I don't find what's in my truck as stock to be adequate. Haven't driven at night yet. I don't want to do LED or HID after reading all the stuff on here as in money, trouble, time, etc.

I have an Indian Chieftain motorcycle and replaced all 3 fairing lights with Osram Cool Blue Intense. Not GREAT, but definitely an upgrade for sure compared to stock bulbs.

So back to suggestions for the truck if needed ..............

I spotted a U tube comparo for after market factory replacements and saw,

Osram Nightbreaker Unlimited

Sylvania Silverstar Ultra

GE Nighthawk Platinum Rated top to bottom.

I don't know if I"d go yellow on fogs, but yellow is supposed to be the best for rain, snow?

Any thoughts appreciated. Doesn't mean I'll go that very route but looking for info.

thx in advance for any responders

 

For the TRD 3rd Gen, there is no higher performing halogen bulb than the 2100 lumen H9. An H9 has no glare cap meaning it is not suitable for a reflector housing, but it can be swapped into the low beam projector which will control glare. It will take output from about 1300 lumens to 2100 lumens while retaining the correct optics for the headlight.

For the fogs, you cannot run an H9 without the glare cap as it will cause glare. Check out this post on glare capped H9s:
https://www.tacomaworld.com/threads...1-not-led-or-hid.435419/page-16#post-17685981

If you want a true plug and play solution that does not require bulb modification, look for high efficiency bulbs like Philips Xtreme and Osram Nightbreaker in the highest +1xx rating you can find. I believe the highest I have seen in GE's Megalight +130 bulb:
https://www.powerbulbs.com/us/product/ge-megalight-ultra-h11-twin

Avoid bulbs that put a coating over the filament like silverstar, as this filters out light and reduces output to achieve whiter looking light.

 

Thanks so much for the info and science around it. So I see the H11's link you provided looks like a winner for High beams. BUT no H9 from GE to "match" and for amber fogs.......... In light of that, what would be your recommendation for a brand of bulb for the H9 low beam to "match" the GE's, and a plug in Amber bulb for the fogs. I don't want to use a chainsaw, exacto knife, and additional harness and don't want to melt anything. I'm grateful for your time.

 

Hey folks, I just wanted to update you that I finished that article I was talking about earlier in this thread and have posted it in the KC subforum (link here) and on our website found here! There's a lot of overlap in the information that is presented here but there were even a lot of tidbits in @Too Stroked and @crashnburn s article above that I didn't know and as such, may have even benefited our article I wrote!

 

H9 = high, H11 = low. Don't use those custom capped H9s for the high beams, any quality German H9 will work for highs. The glare capped H9s are specifically for putting an H9 into an H11 reflector fixture like the fogs. To use them, yes you have to do some manual 'alterations'.

For high beam, any German made H9. Sylvania, Philips, Osram, Volsa are all going to be about equal. There are no reputable cosmetic fancy looking H9s, which really doesn't matter as no-one is going to see your high beam color anyway.

Low beams and fogs both use H11, and the GEs are the current leading best for maximum efficiency in H11 that I am aware of. Unfortunately halogens are really not ideal for changing the output color. To change the color requires filtering the light, which greatly reduces output. If you want true amber fogs, I'd suggest checking out the KC G4 amber LED fogs. It is a complete replacement designed for LED from the ground up with light color coming in at 580nm which is the transition point from yellow to amber. I haven't tried the amber version, but the standard G4s were outstanding performers, more-so than the specs would suggest. And I literally tried every single tacoma fog and pod.

Great write up! A couple very small suggestions if you are willing to hear. Where you talk about raw lumens vs lux. One of the biggest benefiting factors in KC lights is the LED designed reflectors are far more efficient than forward facing LEDs. The raw lumen rating of a G4 will outperform a higher raw lumen rating of an LED pod. Not sure if you want to incorporate light projection technology into that section but food for thought!

Also, while you mention long wavelength light penetrates poor weather conditions better, technically true! It is that the short wavelength light refracts and reflects more causing reduced visibility. Though it may be easier for average consumers to understand penetrating.
Edit: on second thought I’d stick with long wavelength penetrating which keeps it from getting too technical.

All in all, I think KC does a very good job in providing balanced lighting info on different technologies and various uses where they may be beneficial or not, vs many where one lighting platform and technology is the answer for everything.