Tbird taillight LEDs and modifications October 16, 2012, 09:18:47 PM So I started to test some things with swapping the tail lights over to LEDs and ran into an issue that makes it a showstopper until I can get over the obstacle. I had previously purchased a dozen 2W red LEDs to use in the tail lights, side illumination, and third brake light. Having a spare, DIRTY, set of tail lights to play with, I started doing some beam and heat testing. You will find that I started with the lenses dirty, tried to then clean them a bit, finding that I need to polish them up to get them clear again, and eventually ended with just the inner filter lens that I washed with only water. It also needs polishing, badly.Anyway, so I went to test the 2W LED next to the 27W stock bulb being fed 14V to provide about the max output that I'd expect in the car with a healthy alternator. The LED was getting a little under 2W with a ~650mA driver. I'm not using 5mm LEDs due to the quantity needed, and having 200 per light will cause some to prematurely burn out due to taking current sooner than others every time they flash on. Using quality single emitters are best EXCEPT, for the problems noted in this thread.Here is my initial result, the same as hos I tested it on the car. It looks pretty good, and even better in person. The camera makes both lights appear to be about the same level of red, but the stock bulb is MUCH more orange in person - so much that is looks terrible. Can you guess which side is which?The next few shows clearly demonstrate the problem I have. note that the color appears orange in these photos due to the intensity of the light, not that the light is actually orange. As usual, I took photos with a few different camera settings to help show the output, and to get a realistic idea on which bulb is actually brighter by reviewing the dimmest of photos.In person the left bulb, the LED, appears much more intense than the incandescent bulb, possibly due to how vibrant red it is in person. The red is bright enough up close to cause red colors in the room to become orange-ish due to oversaturation. The problem here, as you can see, is that the LED is brightest in the middle of the tail light lens, and very dim around the outer edges. I believe the red LEDs have a viewing angle of only around 120 degrees, causing the directional light I am seeing, much more than 180 degree white LEDs. The incandescent bulb uses the reflector well to fairly evenly illuminate the entire red circle. I like the look of the full illumination MUCH better than small bright spots near the center. The LED also appears as if it may actually be putting out a bit less light than the incandescent bulb.SO, off to test the two bulbs with a THIRD bulb, rated for 300 lumens. I cutout the rear of the third light and slapped the triple red emitter in place. This LED runs at 8v, 650mA with these drivers, or just above 5 Watts. The problem with using these LEDs are the price, and they need much larger heatsinks to be installed. The 2W single LED and 27W incandescent were swapped around so it is now arranged in the photos as 27W incan - 2W LED - 5W LED.So I'm thinking wow, the light is a bit more full, and a LOT more bright. The edges of the red circle are still darker than the incandescent bulb though...what is the best way to solve this? From the side it looks great, but straight back, it just reminds me of the faint center glow of older <1980 cars, a look that I just never liked.Here I am trying to compare the two LEDs directly:So yeah, the 5W one fills out much better, but it is still lacking. Now I didn't want to do this due to loss of light, but I cut out a square piece of polycarbonate and sanded a circle into the middle on both sides, hoping to remove some of the light from the center and move some of it to the outer edges. It's a terrible idea from an efficiency standpoint, but I had to try a frosted lens of some type. I applied it to the 5W LED:Okay, so I can see the outline of the circle a little better. Let's try that at a faster shutter speed to pick up the details of the improvement along the edges:Without frosted lens:With frosted lens:You can see that the middle has lost a lot of intensity and it appears some of the "glossy look" is gone due to much more even lighting. So how does the 2W LED do with a frosted lens? I moved it to the middle/2W light and got this:Okay, so the 2W bulb is just too weak compared to an incandescent. 5W triple it is! Final shots with the frosted lens on the 5W LED:I hope to find a clear lens, something like a double concave, to help distribute the light rather than rely on a frosted layer that consumes light. I'm looking to pickup some 4" bowls of some kind to test as reflectors to help aim any stray light back to the edges of the red circles. With that, just about any double concave lens would work well to shift the light around. I don't know how well a single sides convex lens would help, of course defocused. Only having two of the 5W LEDs, I ordered more and they'll be here in a couple weeks, so I have some time to play with optics in the time being.For tonight, pull my interior back apart and figure out why both my left and turn turn signals unlock my doors on every flash, assuming an alarm box problem........More updates later Quote Selected
Tbird taillight LEDs and modifications Reply #1 – October 17, 2012, 12:14:54 AM I remembered I have some car projector lenses that are 2.5" in diameter so I placed one over the 5W LED. It is getting there VERY well now. Mounting the lens this close to the LED, does anyone know if I should get LONGER or SHORTER focal length lenses? Also should U try double-concave, or stick with plano-convex? I completely forgot about Surplus Shed, a place that sells dirt cheap lenses. I'd like to pick some up around the 30-60mm diameter range to use for this project. I'm guessing a double-concave will cause some odd lighting, but if centered correctly, it could look really interesting.Pictures below - notice how the hotspot is MUCH larger now that the light is being refocused. I figure a reflector bowl and proper focal length lens should get this to where it should be. Quote Selected
Tbird taillight LEDs and modifications Reply #2 – October 17, 2012, 01:34:54 AM Okay, I ordered some 4" recessed lighting units with aluminum reflector, which should actually work quite well if I can incorporate that into the heatsinking. I believe I want longer focal length lenses to get the light distributed evenly, with the reflector there to help bounce it back out the tail lights. If surplus shed's website ever starts working properly again, I'll get some lenses ordered up. 10 lenses of varying sizes for $30 isn't bad. Quote Selected
Tbird taillight LEDs and modifications Reply #3 – October 17, 2012, 02:06:42 AM 5w looks best and i think plain convex would be best , diameter is the question and depth of the arch on the convex also. this is a delta only trial and error will fix.- without convex lense, try a circle cut out of red translucent tape (stuff you temp repair lenses with). place it dead center over the area where there is orange. this would reduce the orange and blend it with the red outline i see on teh 5w led layout.-try C or D cell battery flashlight reflectors, cheapy ones that you prob have a couple lying around the house. that is a pretty steep angle but might be a tighter focal point, may end up being too orangish though.keep up the good work, like to see the expected ampacity reduction overall with tail lamps only.nice work... : ) Quote Selected
Tbird taillight LEDs and modifications Reply #4 – October 17, 2012, 12:29:32 PM Quote from: jcassity;400634this is a delta only trial and error will fix.It's the only way I can ever get anything done. Theory and the real world often do not come close to one another. Quote from: jcassity;400634- without convex lense, try a circle cut out of red translucent tape (stuff you temp repair lenses with). place it dead center over the area where there is orange. this would reduce the orange and blend it with the red outline i see on teh 5w led layout.It isn't red in person, it just completely over-saturates the camera's sensor, and in person, your eyes if you're in the beam. The pictures above of the 5W LED looked like white filled circles on my IPS computer screen for a few minutes last night as my eyes got blasted by the red wavelength. A few minutes later, I could see red again...you gotta be careful when testing this stuff. It IS far more brighter than the stock bulbs, which are pretty bright at 14v. I'd have to measure what voltage I get in the car with the alternator running. Maybe I'll test that tonight.Quote from: jcassity;400634-try C or D cell battery flashlight reflectors, cheapy ones that you prob have a couple lying around the house. that is a pretty steep angle but might be a tighter focal point, may end up being too orangish though.I only have LED flashlights, but also reflectors of that size are going to make the center hotspot even worse, if they do anything at all. With a 120 degree viewing angel of the LEDs, not much will hit the smaller, shallow reflectors, and anything that does will be bounced toward the center, not the edges.Quote from: jcassity;400634keep up the good work, like to see the expected ampacity reduction overall with tail lamps only.With my 3G alternator (like 4th NAPA replacement on the "lifetime warranty"), if I had the headlights, foglights, wipers, tail lights, stereo on, using the smallest alt pulley I could get, after the alternator would warm up, it'd drop to 12 point something volts at the battery since the alternator couldn't keep up. The tail lights would dim to like half their brightness, since they'd be at 11.5v or something, which is about half the output as an incandescent bulb at 14v. Letting off the brake pedal, the voltage would shoot back up to 13.5-14.5v, depending on how the alternator is feeling at that point in time. With the LEDs, first the load will be cut to 20% the original load since the 5W LEDs take much less power. Second, the LEDs are at full power at about 8V (3 in series), with the driver needing to see just under 9V to drive the LEDs at full power. This means that unless I have like 10V at the battery, and a huge voltage drop to get me to 9V at the tail lights, they won't dim. Plus, the voltage drop will be much smaller since the load on the wires will be greatly reduced. I look forward to it all, and being able to adjust the full and illumination levels of the lights by high frequency PWM.I got the reflectors ordered, which have a 60mm opening, then some lenses ranging from 62mm to 80mm to try out. Two bi-convex, two bi-concave, one plano-convex, and one plano-concave. We'll see how it all works when everything arrives, I assume early next week. Until then, I will be cleaning up this set of tail lights and getting the wiring done. I'm also trying to think of ways to change how the tail lights look, possibly even removing the need to have evenly distributed light. I was thinking about a ring 2/3 from the center to separate the intense center beam, and then provide the softer outer glow of an outer ring, with a shadow ring separating the two. I don't know how it'd look, but it's something I'll need to mockup.As for my door locking issue - apparently I found a wire that was hot in ignition, but it would be pulled to ground every time the flashers would flash (no matter the side). I moved this to a different connector's pin and all should be well now. The alarm thought I was rapidly turning the ignition on and off, with it unlocking the doors when it detects the ignition-on to ignition-off switch. That was dumb, but it's fixed and the interior is back in. I now have a huge hole where the radio and EQ/cubby go as I need to finish sanding the 8" screen bezel to get that thing mounted up for the carpc. I prefer to do ANYTHING but continue sanding that. I used too much body filler... Quote Selected
Tbird taillight LEDs and modifications Reply #5 – October 19, 2012, 02:53:44 AM Quote from: Seek;400647As for my door locking issue - apparently I found a wire that was hot in ignition, but it would be pulled to ground every time the flashers would flash (no matter the side). I moved this to a different connector's pin and all should be well now. The alarm thought I was rapidly turning the ignition on and off, with it unlocking the doors when it detects the ignition-on to ignition-off switch. Well this was again incorrect. Whenever I'd switch the highbeam, the wire would go to ground, then back to 12v. Again I moved the wire, this time to a permanent home it seems! A live wire in the middle connector on the left side of the column. I have no idea which pin it is, but the wire on my car's harness in green. So far so good. The cluster looks excellent in the vehicle. Quote Selected
Tbird taillight LEDs and modifications Reply #6 – October 22, 2012, 11:51:56 PM Reflectors and lenses came in. First, I'd like to ask if anyone knows of some reflectors that are about 4 1/4" at the BOWL at the very top? The 4" ones I got are a little small (actual 3 3/8"!!!), and I don't like the lost area of the red lens.Anyway, I figured I'd test the reflector with some lenses and see what works well, or what I like the look of. I only used the lenses where they'd sit in the reflector - I did not do any focal length testing of each lens. The two smallest lenses weren't working all that well, so they are not in these photos. A couple lenses I flipped over to try different sides.Here is what I have to work with:Straight on to the photos:Reflector only, no lens:Lens 1:Lens 2:Lens 3:Lens 4:Lens 5:Lens 6:Lens 7:Here are direct comparisons for all lenses:I think a properly-sized reflector may outdo these lenses imo just because I'm looking for fill, but the effects of some of them are pretty interesting. Quote Selected
Tbird taillight LEDs and modifications Reply #7 – October 23, 2012, 01:48:25 AM I picked up some stainless steel bowls to try, from China. I'll see what local places have, but I may have to wait until the slow boat drops them off. They are 11-12cm diameter bowls that should work much better for these lights. Quote Selected
Tbird taillight LEDs and modifications Reply #8 – October 23, 2012, 10:57:13 PM I like Lens 3 Quote Selected
Tbird taillight LEDs and modifications Reply #9 – October 26, 2012, 01:49:34 PM I was very surprised when the new LEDs arrived in 3 days from purchase. Packaging was a bit over the top from Luxeonstar, but they always over-package the leds. I still need to find some 4.25" reflectors/bowls, if anyone has any ideas about where to get them...I have a lot of spare parts, so many that I'm going to have to move some things out of my LED box into a separate one. My other "electronics" parts box with through-hole mount IC parts is also full, more so than this one :eek: Quote Selected
Tbird taillight LEDs and modifications Reply #10 – October 29, 2012, 09:32:29 PM Received some stainless steel bowls from New York. Ordered Thursday night, shipped Friday, received Monday on the west coast!http://www.ebay.com/itm/140863814412?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649The depth is a bit more than I'd like, but that just means I will cut out more of the tail light housing and using some ABS sludge to permanently attach the reflectors, which will be attached to the filter lens. I will be cutting a hole in one and checking out the mounting options after I get another project on its way and re-sprayed with more primer. Quote Selected
Tbird taillight LEDs and modifications Reply #11 – October 29, 2012, 10:55:13 PM Here is the reflector cut. I think I like the light beam of these reflectors, no lens. The light output is a bit lower in these pictures though, and I'm not sure why. I figure the issue is that the LED isn't actually IN the bowl (will have to use a dremel to enlarge the rear hole and make it fit a larger heatsink), and there is a lot more surface area to hit on the filter lens. These reflectors are much bigger than the last ones, filling out the entire red circles (which are actually oval fyi).Anyway, to the pictures! Quote Selected
Tbird taillight LEDs and modifications Reply #12 – October 30, 2012, 10:54:22 PM Yeah, I just don't know what I want to do. I picked up some 4" round acrylic pieces from TAP Plastics today and tried sanding only the middle, and sanding the entire thing on both sides. The results were noticeable, but I'm not sure I like it. I wish I could find some type of lens that was a cone to help distribute the light better.I'm thinking I will stick with reflector only and later try another tail light using up to 48 8mm wide angle LEDs wired in 4S12P running at 50mA each. 32 may be plenty, but it'd require testing. Quote Selected
Tbird taillight LEDs and modifications Reply #13 – October 30, 2012, 11:27:32 PM The comparison shots below show that the evenness should be MUCH better, but the eyes see more of a hotspot still. I think this is the last comparison I can do before cutting up the tail light reflectors.Frosted middle filter with reflector on left, bare LED on right:Reflector only on left, bare LED on right:Incandescent on left, bare LED in stock housing on right: Quote Selected
Tbird taillight LEDs and modifications Reply #14 – October 30, 2012, 11:44:27 PM Aaaaand, if I use some plastic that would diffuse the light well, I lose way too much output. Quote Selected
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