LEDs are old technology, first created in 1927. It has taken nearly 100 years since their creation, but they've finally reached the mainstream, with the technology in use for everything from computer screens to electronic signs to car headlights. Many, if not most, modern vehicles come equipped with LED lights in their headlights, taillights, and indicators.
If you're driving an older vehicle, though, you may still be using non-LED light bulbs. Incandescent and halogen bulbs have their place, but LEDs have numerous benefits that make an upgrade a potentially good idea.
So, can you use an off-the-shelf conversion kit to upgrade from your current headlights to LEDs? If so, what considerations should you keep in mind? It’s not as simple as just swapping out some bulbs and calling it a day.
Let's start by discussing the different types of headlights and how a LED conversion will work with them.
There are two main types of headlights; projectors and reflectors. Knowing which kind your vehicle has is important, as it determines what you need to do to swap to LEDs.
Reflector headlights are the oldest and most common style of headlights. The concept is simple: you have a bulb in the front of your vehicle.
A bulb casts light in all directions save for where it connects to the power source. 90% of that light is going in directions other than in front of you, and being wasted. So, the design incorporates a reflective bowl. This bowl is positioned with the bulb at its center so that the light the bulb casts in angled directions is reflected off of the bowl and projected back forward. This greatly reduces light waste and spreads more light further forward in front of the driver. Flashlights work the same way by catching the light and aiming it where it is needed.
Projector headlights operate in the same way, except between the bulb and the world outside of your light housing, there’s a lens.
This lens captures and focuses the light passing through it, directing it further forward and in a straighter path. The light that projects forward is more focused and brighter, with less tertiary light waste. They are essentially an upgrade from the reflector-style headlight design and are more common in newer vehicles.
The problem you may encounter with reflector headlights is that the reflector bowl is specifically designed to work with one specific halogen bulb. These bulbs are predictably designed to a specification that was known to the car’s designers when it was designed. This means the reflector bowl is carefully designed to capture exactly the light cast by that bulb.
When you change the bulb design, you change how the light is cast. Light from LEDs is not quite as omnidirectional or as balanced as the light from a halogen bulb. This means it doesn’t hit the reflector bowl as evenly.
When an LED is plugged into a standard reflector headlight bowl, the light it casts forwards is unbalanced. It can be extra bright in some directions, forming hot spots, or extra dark in others, forming blind spots. If you have a hand flashlight that can adjust its focus, you know exactly how this works. This imbalanced light can leave you with blind spots in areas you’d like to see and can focus light in strange directions, potentially dazzling oncoming drivers.
Typically, if you want to use an LED bulb in your reflector headlights, you’ll want to buy a conversion kit that is specifically designed for your vehicle. The reason for this is that you want not just a new bulb, but a new reflector bowl as well. The reflector bowl needs to be designed to fit your existing headlight housing; it’s harder to swap than simply changing a bulb.
The other option is to find an LED conversion kit that is specifically designed for your particular vehicle. Since the reflector bowl is a known design, LED manufacturers can design an LED bulb that takes advantage of that specific design and can cast bright light - even light using that reflector bowl.
The third alternative is to purchase an entirely new headlight, housing and all, that is designed for an LED. This kind of retrofit is ideal for some vehicles, but may be difficult or impossible to find for others. Such kits are only made for specific vehicles, and your vehicle might not be covered.
Unfortunately, a new bulb and a new reflector bowl are not the only considerations you may have when swapping to an LED headlight. There are a few other concerns that may only be apparent when you start looking for a specific swap.
LED lights have been around for a while, but they require a few considerations to operate at their peak. LEDs can last for a very long time (unlike filament bulbs, which burn out eventually), but they need to have both a consistent voltage and a way to dissipate heat. Heat is the number one killer of LEDs. LEDs themselves are tiny; the bulk of an LED headlight bulb is a combination of the electronics that keep it working and heat sinks to dissipate that heat.
When replacing your existing halogen bulbs with LEDs, you’ll need to make sure your LED has appropriate heat dissipation. More importantly, you may need to replace some of the electronics in your vehicle as well.
LEDs consume much less electricity than comparable incandescent bulbs, so the electronics in a vehicle designed for halogens are used to pumping more voltage to the bulb. Swapping the bulb to an LED will overcharge it, and can burn it out, cause excess heat generation, or otherwise damage it. Usually, this means an accessory kit that steps down the voltage, though in some cases it may be a complete replacement of existing electronics.
Another consideration you might have is the legality of aftermarket LED replacements. In some places across the country and around the world, LED headlights are occasionally a moving violation, though poorly-regulated and rarely punished. It varies from state to state, both in terms of the extant laws and the enforcement level.
To be clear, LEDs themselves are not illegal, nor are LED headlights. Only some aftermarket LED kits will give you issues, typically for the reasons stated above; improperly installed LEDs cause poorly directed light to dazzle other drivers, while not necessarily gaining you any performance from your headlights. This all varies quite a bit based on the headlight kit that you decide to install.
If you’ve decided that you want to use LEDs for your headlights, here’s how you would go about it.
Step 1: Determine whether your vehicle has reflector or projector headlights. A vehicle with projector-style headlights can typically just swap the bulb to an LED and be fine. A vehicle with reflector-style headlights might need a new reflector bowl, a new housing, or entirely new headlights, depending on the make and model of the vehicle and the design of its headlights.
While you’re at it, you can check to see if there are legal issues in your state. Some states (and some countries) make it illegal to use LED headlights if your vehicle was not designed for them in the first place. This may or may not be a concern for you, but if it is, you may need to use a more comprehensive overhaul kit rather than a simple bulb replacement.
Some vehicles consider the headlight style part of the overall trim level. In these cases, the cheaper trim levels usually have reflectors, while more expensive trim levels have projectors. In these cases, you may be able to find an entire projector-style headlight replacement kit. This is the ideal option; projectors are better, brighter, and more even than reflectors, and an LED swap kit for projectors is much simpler and easier to use. If you can find a projector-style headlight kit, go for it.
Step 2: Look for conversion kits for your specific vehicle. LED manufacturers who focus on headlights may produce specifically-designed kits for your vehicle’s make, model, and even trim level. These kits include everything you need to swap your headlights from their existing halogen (or xenon) bulbs to LEDs while keeping the headlights legal to use. This might include electronics, fans, housings, and more. You should search for your vehicle and see what kind of kits are available - if any.
If no such kit is available, you may need to do some research of your own. Look into what style of reflectors are used in your vehicle, and how an LED bulb might perform in that housing. Depending on the age of your vehicle, this may be more or less difficult to research.
Step 3: Determine if you’ll need additional enclosures, electronics, or reflectors. Typically, you will encounter one of two circumstances. In one case, you may find that there are specifically-designed LED bulbs made for your vehicle, which can be swapped in with no other changes. This is most common with very popular, common vehicles. Less common vehicles may need additional elements, like the reflector or the electronics. You’ll need to determine this on a case-by-case basis.
Step 4: Swap any necessary parts. Swapping out your headlights, whether it’s the entire enclosure or just the bulbs, will also vary from vehicle to vehicle. Your vehicle’s manual will likely give you some instructions for swapping a bulb, though if the vehicle uses xenon bulbs, it may simply direct you to a dealer due to the hazard of the voltage in the event you break the bulb.
In that case, you will want to look for the mechanic’s guide for more comprehensive instructions on the maintenance of your make and model. There may also be simple YouTube videos or other online resources, depending on your vehicle.
Step 5: Test to make sure your headlights are properly aligned and balanced. Once you have performed the swap, you should perform short, medium, and long-range tests with both your low-beams and your high-beams. This helps ensure that you’re not blinding other drivers, that you don’t have blind spots in your headlight direction, and that your LEDs are performing better than your old halogens.
The other modern alternative to halogen bulbs is the HID light or High-Intensity Discharge bulbs. These, also known as xenon bulbs, use tungsten and xenon to produce much more light than a traditional halogen bulb. They’re also a common aftermarket swap and are an alternative to LEDs.
HIDs can be a viable swap for some vehicles, particularly those with reflector headlights because they’re still filament bulbs. They don’t have the directionality issues that LEDs have, so they’re not going to have blind spots or misdirected light.
On the other hand, HIDs have a few drawbacks that prevent them from being an ideal option. For one, they have a bit of a warm-up period before they reach full brightness. This can be anywhere from 5 to 30 seconds, which is a lot of waiting time if you’re trying to run your lights in an emergency.
Xenon bulbs also require a high voltage current to power on, meaning there’s typically a capacitor in the line somewhere. This capacitor can discharge if you short the bulb while changing it, and that can be dangerous.
Overall, LEDs are generally a great option over HIDs or halogens, if you take the proper precautions and make sure they distribute light evenly and brightly ahead of you. The only hazards posed by LEDs are caused by improper installation, which is a problem that must be addressed eventually with proper instructions or regulation. For now, you simply need to do what you can to make sure your headlights are safe and road-legal, regardless of which option you decide to choose.
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