Homemade LED TailLights

[63BlueMGB]

It has been to cold out the past couple of weekends to work on my car, So I tried to come up with something that I could do inside. I came across an article about LED Tailights and wanted to see what my options were. Did some research on what was on the market and did like what I fould (price and look). So for about 30$ each and a weekend I made my own. Etched and designed my own circuit and board. Pictures are not great but you get the Idea. Process wasn't as hard as I thought it would be. When I get my car completed I will have to measure voltages and current throught the circuit to make sure it is set up correctly so I get the maximum life out of my LED's. So what do you guys think

[TKMad]

Looks great!

[HealeyRick]

If someone rear-ends you now, her license better read "Helen Keller".

[mgbv81970]

Nice job!  ( I plan to copy eventually  

Scott

[classic conversions]

Like what I see.

I would like more info. I would like to make the turn signal an arrow, the stop two opposing arrows and tail light circles.

Can it be done???

You got me thinking specially after I bought a set.

[Dan B]

Or how about Octagonal red lights like a stopsign for stop lights?  Perfect for MGs!!!!

[63BlueMGB]

Thanks to all that replied! I was really excited to see how these came out and what people thought. This process is really not that difficult to repeat anyone could do it. However, since I have had them completed I have already came up with a couple of things that I would do different and maybe a different pattern. The only limitation that I could really find when doing these is the size of the boards and the size of the LED's (there are a number of LED out there to use) and getting everything uniform. My tailight is a later version '63 and I am not sure how they differ from the earlier models, so the way the Lens fit in these, it is two different compartments and as you get farther away for the base the lens narrows so that limits the size of the board. It is really all about preference and what you like. I like lines so that is the way I decided to do mine, I really wasn't sure how they were going to turn out but after seeing them, I would have made my lines vertical instead, I think that they would look better on the car , and go better with the MGB Lines. I am thinking about putting together a how to, but need to check some things out first and really to see if anyone is interested? Thanks

[Moderator]

Fantastic!  Congratulations on a great result.

I'd love to see a to-do article come from this, especially if it emphasizes fabrication techniques that have wider applications.

An LED taillamp project has been on my to-do list for at least twelve years. (Back in the late nineties I had easy access to cheap LEDs through my work.) The biggest reason this hasn't moved to the top of my to-do list is that LED technology changes so very rapidly. Cost is coming down quickly, even while the individual diodes get brighter and brighter. Having seventy-five LED's per taillamp looks kinda neat... but by using newer/brighter LED's you could eliminate a lot of solder joints! It's just a matter of time until they're so bright that only two or three LEDs are needed for a whole taillamp fixture.

These are off-the-shelf sealed clear-lens truck taillamps that could simply be installed underneath MGB lenses:

more info: http://www.pmlights.com/products.cfm?cId=1&fId=57&pId=3781

Notice that they only have 20 LEDs per lamp. I believe these particular lamps can be bought new for about $36 each.

[classic conversions]

Is the how to out yet :-)

[roverman]

Out in CA, we're not so shut-in,(don't hate us), perhaps an article including #1157/etc. led coversion bulbs ? Twist them in-done. I do like your work and patience. Cheers, roverman.

[BlownMGB-V8]

The 1157 bulbs have been around for at least a decade, originally they were very voltage sensitive and would burn out, at which point they would short the inputs and sometimes burn up the vehicle wiring, but no doubt they have gotten better.

I recently bought a 20 watt warm white LED off evilbay that operates at battery voltage. I think it is a rectangular grid array of 20 1 watt elements created on one substrate, giving an illuminating area roughly a half inch square. I took it outside the other night with a battery and lit it up and it easily puts out enough light in a wide enough spread to be used as a supplemental or fog light. (would probably need a top shield) Used behind the stock back-up light lens it would be an extreme back-up light. Used in red or yellow colors it could easily replace the brake and turn signal elements but would be far too bright for running lights. Naturally it produces cool light but they do sell some pretty massive heat sinks designed to be used with these and I haven't tested yet to see how much heat it actually produces. After being on for 5 or 10 seconds it was a little warmer to the touch but certainly not hot, so for a brake or turn signal application you might need a heat sink and you might not. But the idea is that you have enough light intensity and spread in a small enough package that you can replace the bulb directly, or perhaps the bulb and socket, and take advantage of the stock lens' Fresnel pattern.

The big advantage of the 20 watt version is that it has the correct operating voltage. Excessive brightness could be an issue. The rectangular shape and package size could be an issue. Placement of the brake and running light elements crammed right against each other could be an issue. Smaller 1 and 5 watt round pattern LEDs are available which could make ideal running lights if equipped with the right voltage dropping resistor, as well as larger 50 and 100 watt rectangular ones. Were the required voltage available, the larger elements could probably be used for main lighting if equipped with an appropriate lens. Or, multiple 20 watt arrays would probably work if you could come up with a suitable focusing lens or lenses.

Jim

[classic conversions]

Jim, I know very little about this stuff.

If I run LED's 1157 replacements or an LED panel as shown in this thread, would I need a different flasher.
Totally agree with you, to bright can cause distraction to the other driver.

New autos have LED lighting but there are not as many LED bulbs, I just took a look at my friends Audi which is all LED.
Audi uses less bulbs but larger. They are visible without being intrusive to the eyes.

What would you recommend Jim, or any one else.

[BlownMGB-V8]

I'd suggest doing a search on ebay and checking them out as a first step Bill. You can search LED 20 watt and get hundreds of hits, or narrow it by color, etc. I think the warm white 20 watt was ten bucks with shipping but you might get cool white for less. At least there seem to be more of them. But look at the voltage specification as they do vary, usually with a range of a couple volts. On this one they just spec'd it at 12v which is very ambiguous but I decided to give it a try and it runs very well off a spare battery. It's possible that system voltage could fry it as that could be a couple volts higher, or it might tolerate it without any problem. I haven't tested that yet and I'm in no particular hurry. I'm just planning to play around with it for awhile to decide what I want to do with it and which ones are the best choice. The red and amber 20's seem to want around 10-12v and cost a little more. One 50w white is about 35 volts, but so is one 100w warm white so it depends on how they are wired and it should be possible to find a 100w that takes around 12v. Price does go up though and as time passes they will get cheaper.

There are power supplies too, which would give you a very stable light output, but I've tester led's at a much wider voltage range than their specs and they worked fine. Life might have been compromised but when they fail it's sudden so maybe not that much.

Anyway I just thought y'all'd want to see this.
http://www.ebay.com/itm/Y-20W-Cool-White-High-Power-1600LM-LED-20watt-Lamp-Bulb-Light-DC-6500K-/150763120164?pt=LH_DefaultDomain_0&hash=item231a2ea624

Jim

[Dan B]

http://www.customdynamics.com/motorcycle_led_bulbs.htm
http://www.signaldynamics.com/index.htm
http://members.misty.com/don/ledx.html

These are some links from a thread on the TR7 forum.

[classic conversions]

Thanks Jim.One more question Would LED's require a different flasher?

[BlownMGB-V8]

Maybe not Bill.It really depends on the wattage of the bulb. A standard 1157 has about a 21 watt bright element and a 5 to 8 watt dim element, and by now we should know watt is watt, so if a 20 watt LED can be used it ought to work just like an 1157. I'm guessing it'll need an opaque diffuser of some sort between the LED and the tail light lens though, because 1157 LED lights draw about 8 watts total and the light output is going to be way up there.

Jim

[Bill Young]

Most common flashers are made with a bi metallic spring that bends as heat is applied. The heat comes from the current carried by the lamps. If you use lamps with lower wattage in some cases the flasher won't heat up enough to work or will flash very slowly. If that's the case then there are solid state flashers available that work on an RC type circuit and flash at a constant rate no matter what the load.

[ex-tyke]

LED specs and performance aside, for best results a red LED should be used in a red tailight lens, yellow in yellow, etc. (A red lens will filter out all but the red portion of the light).
It follows that using a white LED in a red taillight will give inferior results.

[BlownMGB-V8]

You'd have to look at the level of red/green/blue required to get white. (Apparently not much blue needed) and the result should be very similar using a warm white LED to what you get with incandescent. Both are quite inefficient but what matters is your objective. If you want the same flasher rate you want the same wattage load and will just have to deal with the extra light by stacking inefficiencies. As for the amber, some testing is needed. Diodes put out a single discrete light frequency so stacking three diodes (RGB) does not necessarily give you a full spectrum light and the amber frequencies might be low.

I've used those solid state flashers for towing and with the trailer lights connected they worked just like the old mechanical flashers. So I'm not sure how they are wired but keeping a steady rate with different loads wasn't something they were doing well. It's been awhile though and they could have gotten better.

Jim

[BlownMGB-V8]

Did some testing with a late MGB lens. Plenty of light, much more in the amber lens than the red but extremely bright in both. Might get by with it on the red but the amber lens will definitely need a diffuser. It almost forces white light through the lens! A lower wattage LED will certainly be needed for the running lights. A heat sink of some sort would be a real good idea for the brake light at least.

A 10 watt might work with a 3 or 5 for the running lights. Those would need a dropping resistor to reduce the current to the right level but would draw less power and generate less heat. One with a large built in heat sink might be adequate.

Jim

[63BlueMGB]

Jim,  Could take a picture of the LED light behind the lens, It would be interesting to see what a solid bulb looks like compared to multiple. Just to give people an idea between the two.

One thing that is going to effect the LED light is the lens. With the stock tail lights, they use regular bulbs and the brightness of the bulbs is directly affected by how shiny the tailight case they are in. By bouncing the light around in the housing, it gives the appearance of being pretty bright! However, LED's do not use this concept. LED's have a set degree (angle) of light output which is determined by the size and type of LED bulb, and can vary anywhere from 20*-360*. For this reason, they generally do not light up surrounding areas inside the tail light housing like the standard bulbs do, and it can make them seem less bright, However with thanks to miniaturization that is where the 1157 bulb using SMD LED's is becoming more effective replacement than a board type application, just plug in ready

When considering LED's, while they are relativly the same they to do have major differences. One of the main differences with A SMD(surface mount device LED like in a 1157 bulb, the flat looking bulb) and the type I used in my application a (5mm LED) is the beam pattern of the LED. Most of the size of a 5mm or 3mm indicator LED is the epoxy package–the actual LED junction is quite small. With SMD LEDs, you don't get much extra packaging, just the glowing bits. Without the epoxy package focusing the beam, they tend to have wide viewing angles. The bulb I used, has a viewing anlge of 110-120 Degree's, and most SMD have a much wider pattern of 140 or greater. So when picking LED's you have the look at the LED Characteriscs and how they are formed.

Another difference is handling, handling SMD led is difficult. They come in a tape reel packaging designed for automated assembly. Solder reflow is the usual way to connect these to your circuit board, but for home hobbyists with steady hands, a fine-tipped soldering iron may get the job done for you. Be quick–five seconds at 260°C can cook them. And I must say very time consuming with the something that small, the 5mm were time consuming enough.

It really comes down to preference and what you want to do (design, function, safety, and it is really your preference). You have more creativity with a LED Bulb and how it is used than a smd led and I think the circuit design would be simplier for a hobbyist. There are multiple bulbs out there you just have to do some research and how you are wanting to apply it to your application. I am working on a HOW TO and will post it soon! This application has multiple uses and it is always fun to try and learn something new.

[BlownMGB-V8]

The LED I've got is a flat matrix of perhaps 20 small square grids, each of which probably have hundreds of light sources, if not more. The whole pattern is about 1/2" square and sits on a small plate with connector tabs for power.
http://www.ebay.com/itm/180792688414?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

These new lighting elements have a lighting angle specification of 140 degrees but I can tell you that if you can see the element at all it will put spots in front of your eyes so 180 is probably closer. Clearly you don't need more than that for a tail light. It brightly illuminates every edge of the late MGB amber tail light lens when the lens is held in front of the LED with no reflector structure or anything else. I'm telling you, it's a LOT of light.

The stock lenses are designed for a point source of illumination. They look a little odd with multiple discrete LEDs but work ok. This is a point source. It will work but will require the original socket (and reflector maybe) to be replaced with a heat sink.

Jim

[BMC]

Nice Job.

I know plenty of people who swear they can build them for $10 for a set but think you have a more realistic idea of $30 per unit.

Did you add any spike protection or else? Are both boards used for brake or only one for brake and one for turn?

-BMC.

[BlownMGB-V8]

Brian, I know you've been the point man on LED tail lights and have done a great job with the 1st generation units. Really great looking tail lights btw.

My second 25w LED came in, I think I'll use these for the backup lights. Can't be done for $10, no how, no way. Each LED array cost ten bucks by the time you pay shipping from China. But there's no way you can buy a brighter backup light bulb that's even remotely feasible. The next step is to fashion an acceptable heat sink that can take the place of the stock bulb socket. Commercial heat sinks are available, but they are HUGE. I think probably just a thick aluminum plate, maybe 5/16 or 3/8" thick would do the trick, no longer than they will be on, and may dissipate enough for continuous use. These are the right voltage for automotive use so no power supply is required, though with a higher voltage alternator they might not last. I think anything up to about 15 volts they'll be happy.

As for other uses, this array can be oriented horizontally and should be good for fog or supplemental lighting. A heat sink in the form of a piece of aluminum strap  would work fine and a number of them could be lined up above or below the bumper. The issue would be to come up with a lens or clear weather cover, plus a mask if they are intended for use in traffic. The bumper (CB) could serve the function of a mask. (They are definitely bright enough to puts spots in your vision. Big ones.) Bear in mind, these are 25 watt bulbs and more efficient than incandescent. The low beam of some headlight bulbs is only 35 watts, so it is a serious light source, far too bright for tail lights, and marginal for back-up lights.

However... lesser wattage single LED elements and arrays are available. The trick is to find something in a lower wattage that runs on automotive voltages. I would guess that a 5 watt for the brake lights and a 1 watt for the running lights would be in the ball park, and maybe a 3 watt for the turn signals (especially if it uses an amber lens) but the only bulb in that range that I have so far is a black light in the far ultraviolet wavelength so it isn't a good indicator of light output.

I suspect that you could use a flat plate inside the bodywork for the bulb holder and heat sink with threaded holes for the lens screws. The trim I'm not so sure about, as I don't have an early set of lenses to play with. The electrical connection could be via pigtail with a sealed connector which would insure continued retention of system smoke for long term reliability, and soldered connections to the LED elements since they have a near infinite life, provided system voltage remains at nominal levels.

That leaves voltage. Most LEDs can tolerate a variation in operating voltage of 25% without difficulty, and will function with variations of 50%, though perhaps with some output reduction or reduced life. That means that a simple dropping resistor of suitable wattage and value can make them perfectly usable in an automotive environment. This would be fine for a back-up light. But a voltage regulator is clearly much better. Where the trouble comes in with a resistor, especially with arrays, is when an element burns out. If it is a series parallel array, one series will go dark and the current draw will drop, which raises the voltage, cascading the failure. Same mechanism with discrete bulbs. This was the problem with the original 1157 LED bulbs and led to a short circuit which could then burn out the vehicle wiring. Inexpensive tab mounted voltage regulators can easily handle 5 watt loads at a cost of around a buck or so and would be suitable for use in a tail light assembly where reliability is a major concern. The regulator will  hold the correct voltage regardless of how many element may fail, allowing the remaining ones to continue to operate correctly. Overall light output will drop off, but the bulb itself will continue to work.

For the 5, 3 and 1 watt bulbs there are two options. The best is to find arrays that operate at automotive 12v levels so that no dropping resistor is needed. Then if one series of the array fails it is not a problem because each series needs the nominal 12v supply, which does not change. The next best option is the regulator chip which requires additional soldered connections, mounting to the heat sink, and protection from the elements. The dropping resistor is an option but not a good one unless a separate resistor is used with each individual LED element, all of which are in parallel with the supply voltage. Spike protection typically consists of a voltage limiter such as a zener diode which is cheap and rather easy to add to the input wires, one for each circuit. The Zener has a breakdown voltage, say 16v for instance, and conducts anything above that to ground. These were common in the charging systems of British motorcycles a few decades back and vastly simplified the circuitry, essentially replacing the entire voltage regulator with one simple solid state component. The problem was that it had to handle a lot of current on a continual basis. We wouldn't have that problem here.

I will send an inquiry to the LED sellers I've bought from, maybe they have something suitable. I think a single 5, 3, and 1 watt warm white LED with diffuse integral lenses mounted on a single backplane centered in the original bulb centerlines should make an excellent taillight replacement for the MGB. I'm not especially interested in competing with Brian for the limited market on this, but I am willing to help in the development.

Jim

[63BlueMGB]

Brian,

Thanks for the compliment. Currently I have them set up on a parallel circuit with just resistors, I did look at putting in a voltage regulator in for voltage stabilization, decided against it and wanted to see how they would work before I put anything else on them. I plan on redoing them after awhile and maybe make some changes. Currently boards are set up one for brake and one for turn. But If I decide to convert them for both that should be pretty simple. Thanks for replying