First of all, this is purely a thread about the advancement of LED tech as a legitimate replacement for halogen bulbs in reflector housings. I know this is a knee-jerk topic where once someone reads LED and reflector headlight they automatically go into attack mode about blinding other drivers. As tech advances, it's prudent to observe the changes to that tech and not fall into a constant loop of luddism.
Thank you for posting this!
This is not a post about breaking the law or about the ethics of modifying headlights. It is only about the tech and how close it is getting to halogen parity. Just nerdy car people being geeky about cars.
In the last several years, LED bulbs have come to the point where there is no practical desertion between halogen and LED in terms of light focus and spread. The main variables now are brightness and color temperature.
The main contention with LED bulbs is that the LED emitters themselves on many models, for many years, were too far spaced apart, enough that the optical design of the reflectors would be out of alignment with the point sources of light from both low and high beam emitters. The newer designs are getting very close to the same specs required of halogen bulbs, and seem to be falling well within the margin of error for proper optical alignment.
There is a very interesting website, called bulbfacts.com where LED lights are put through controlled tests to determine all pertinent factors in what makes a bulb a good choice. One of the main pieces of data are the pattern tests done in reflector housings.
There is a great comparison table at
https://www.bulbfacts.com/led-kits/chart/
One of the top performers in their tests for light scattering is this model
https://www.bulbfacts.com/led-kits/reviews/lumibright-xt1-led-kit-review.html
If you check out the visual test, it's quite impressive how well it maintains the cutoff in low-beam mode. While it could be argued that they are ridiculously too bright regardless of light focus, the fact that the light is so well controlled in a halogen housing is very impressive.
An interesting thread was started by a fellow (user: spiderman302) who claims to have helped advance the newest generation of LED bulbs designed with both the proper emitter locations and proper low-beam cutoff.
The new F2 LED by Evitek has improved focus by using a thinner copper mounting plate. If you have been looking for a DOT compliant bulb, you need to...
advrider.com
One important aspect of his post is a cutaway view of a halogen bulb and a new model of LED. As you can see, the LED emitters are getting incredibly close to the same width and point source as the halogen, even including the same cutoff dome and offset emitter for high beams.
Image credit to spiderman302 from
https://advrider.com/f/threads/h4-l...me-focus-as-h4-halogen-bulb-new-2018.1286743/
The mounting plate for the emitters on the new design is 0.037 inches thick, where as older LED designs might be in the 0.235 inch range. A standard H4 halogen element is 0.068 inches wide.
Below is one of the newest designs for LED compared to halogen. Notice how the cutoff dome and offset of the low and high beam emitters are very similar.
View attachment 39170View attachment 39171
When looking at the patterns produced by LED H4 bulbs in reflector housings, the best performing models are clearly within the range needed to perform in parity with halogen bulbs. While there still might be some light loss in certain areas of the beam pattern, there is no added percentage of light in areas where there should not be any added glare for oncoming drivers.
Going forward, I think the problem of poor focusing from LED lights is going to be a non-issue for upgrading existing halogens. What might be a new issue and something worthy of debate, is over the brightness and color temp of the bulbs. Thankfully, there is a HUGE spread of LED lights that vary in brightness and color temp. Some are even capable of close proximity of the color temp and lumen output of halogen bulbs.
I highly recommend checking out the bulbfacts.com website.
EDIT: Another aspect not often covered in LED conversions, is the fact that they emit very little heat through the light pattern of emitters themselves, at least enough to heat up the lens of the housing. LED lights will get covered very quickly in snow storms and be a very dangerous situation. This has to be taken into major account when swapping from halogen to LED. If anything, when using LED in an area prone to snow, carry a set of halogen bulbs you can swap in for added snow and ice melting ability. The halogen bulbs can increase the temps inside a housing by 50-60 degrees over outside ambient temp. (numbers are just a rough guess on my part, but much hotter than LED, no question.)