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MG TD TF 1500 - Universal LED Tail Lights

Hi all,

I'm starting a new thread on this issue. I hope that's OK, my thinking is when threads get excessively long people would prefer a new thread, but is that bad etiquette? I don't know.

Anyway, I've completed the 2nd rear tail lamp (and I'll start working on my front running lamps soon) using an ultra-high-power LED which runs cooler and lasts longer and is MUCH brighter than stock. I'll be looking at how to produce these in volume in the coming months.

Others brought up the issue of whether these might fit on other cars apart from MGTD's and this I don't know.

I'm going to meet with a TF owner down here in Tucson to see what is needed to make it work on both bodies; but my question is simple, does anyone here on the forum know of other makes/marks/models & years that they think MIGHT be fairly similar? My goal is to develop as universal a bracket as possible so it will fit in a wide range of cars and thus offer more of a market. What about Minis and Rovers... and there even might be American cars out there that might be a close fit too.

So if anyone has ever noticed that a tail lamp assy in one car seemed pretty similar to their MG... let me know!

Thanks for the input!

Anyone interested in signing up for an early production version of my LED lamps, let me know via email and I'll try to work up pricing.

Geoff Baker

The early TD tailights (rectangular) were a pretty common one....think Austin, Morris all used them. I know I have seen them on A40's(maybe 30's) and saw an extra pair added to one to add turn signals....
gblawson(gordon)

The sockets themselves are the same in most British cars, Big Healeys, Sprites etc. I bought halogen bulbs for the Healey (glass lense, not plastic) about 10 years ago in Stowe and they are twice as bright than originals. Am I understanding that the socket, bracket would be different?
R.AF. Robert Finucane

Yes, I won't use the original sockets (once called 1157 bulbs, I think they are now called BA15's.

My LED mounts on a bracket that fits the base bracket that holds the bulb mounting. The bulb mounting can simply be removed.

Using a bulb socket can cause stray voltage as you insert and rotate the bulb which can damage an LED. To avoid this, I've come up with a simpler alternative... something that requires ZERO change to the existing wiring. All you have to do is pop the wiring off the bulb mount, which on a TD of my vintage leaves you with two bare wires and one with a bullet connector. Nothing is cut. The non-bullet wires will pop off when you depress the spring mechanism that will release them.

I'll be doing my connections using a standard mini-screw twin connector which lets you just stick the ends of the wires in and then screw them into place, nothing has to be cut or changed.

With the bullet-ended ground wire, I've found I can use a standard US gauge female bullet connector; I just have to expand it slightly with a drift, and it fits nicely. I'll look to see if I can get actual British old style gauge female connectors. But in either case, the wiring remains untouched, nothing has to be cut, crimped, or soldered.

Here's a very lousy picture of the connector ends.
Geoff Baker

No, HERE's the lousy picture. :)


Geoff Baker

Geoff,

Sign me up.

I'm going to need them for my PA (negative grnd), and after that, my TF (+ grnd).

The PA electrics are getting a complete modernization. Bosch distributor with pertronix; solid state regulator (hidden under the stock case); LEDs for dash lights and a Bosch double-ended generator from an old, air-cooled beetle.

Some needed electrics for the PA are out of my budget, including original Lucas ST38 "Pork Pie" tail lamps at 35 each. I found an almost identical equivalent at Walmart for $5 that uses the 1157 bulb, and fortunately, there's all kind of room inside there for the BA15 socket ass'y, and this is negative grnd.

I also plan to install LEDs in the wing/parking lamps (same as TC-TF) and hope the BA15 can fit in there too.

The flasher still mystifies me and I guess I'll have to deal with that after I have everuthing installed. It seems to be an issue of load, and I think I can handle that.

Thanks for all you're doing Geoff. Despite being an Electrical Engineer (grad 1956) most of this stuff is hocus-pocus and I'm grateful for your expertise.

... will keep my eye on this thread.

Gord Clark
Rockburn, Qu.
Gordon A Clark

"Using a bulb socket can cause stray voltage as you insert and rotate the bulb which can damage an LED."

Uh, if you are talking about ESD, not really. And anything else isn't an issue with the power off.

There are tons of makers of LED replacement bulbs that fit into standard bulb sockets without any issues with "stray voltage", whatever that is.

Scott
Scott Linn

Scott, you are perfectly correct - when talking about normal low power LEDs.

Most LED auto light manafacturers use these in arrays - up to 50 or more, to generate enough light to match an average stock bulb. And when using these low power LEDs there are typically no issues, including polarity. That's why they are common, and popular. Unfortunately, they don't hold a candle to the average stock bulb; I bought about twenty different led bulbs to test, and not one produced as much light as a stock bulb. I still have some in a drawer, a couple of ridiculous ones with 47 LED or something which were TOO BIG to fit in most housings and STILL didn't put out enough light to match a standard bulb. I ended up making my first LED system using an array of 73 LEDs which performed on a par with a stock bulb... but the whole aim was not to match but improve!

High power LEDs (in the 1W and above range) are very polarity sensitive and require constant current drivers. They are an entirely different class of device, and with significant issues - polarity, current fluctuations and heat being the primary issues.

(Interestingly, they don't seem to need load resistance as do low power LEDs; my current design works fine with a standard flasher!)

A year ago I bought several for testing purposes that were 5W (roughly comparable to the power output of the 3LED stars I am using now) that came with BA15 bayonet fittings.

In turning the bulb and depressing it into the socket, two blew immediately. I returned the rest.

The manufacturer no longer sells the 5W versions.

Between the imprecision of the bulb manufacturer and the imprecision of the housing, when inserting and twisting a standard two circuit bulb into a BA15 bayonet housing, it is possible to create sufficient voltage and current fluctuations that can damage a high power LED.

Not being an electrical engineer, I do not have the means of testing this further - I just know I won't make a high power LED using a bayonet base... I could not offer any worthwhile warranty on my work. If anybody wants to wire my LED into a BA15 pigtail they are welcome... I just won't do it myself, and I won't warranty any bulb than anyone puts onto a BA15 base.

You're quite right, none of this would matter if people inserted the bulbs with the power off. But in my experience, people insert bulbs with power on most of the time!

I'm sure that soon manufacturers will get around these issues by including circuitry designed to handle such loads; but so far it appears they do not.

My solution is to avoid the problem by using direct wiring connections. Installed properly these LEDs will last 50 to 100 thousand hours and are much brighter than stock. Plus, I can wire them for either negative or positive ground; whereas all other high power bulbs on the market with bayonet bases are currently all negative ground.

Hope this explains it better.
Geoff Baker

Geoff,

Thanks for hijacking my original thread while I was off on vacation in Portugal. Just kidding.

If you make an LED tail light for the round 53TD lights with positive ground I will be your 1st customer. Keep up the good work.

Cheers,
Jim
James Neel

James, that's the plan. I'm going to meet with some Brit car owners tomorrow at 7 and I'm hoping to get the precise dimensions of the round taillight off of them.

Geoff
Geoff Baker

Hi Geoff,

The "blowing immediately" didn't have anything to do with the LED or "stray voltage", just the polarity of the drivers. This would especially be true if you plugged a (-) ground LED bulb into a (+) ground TD socket. You didn't mention if that was the case or not.

The high-power LED taillamp replacements work fine when the polarities are correct, and are usually put inside 1156/1157 compatible bulb footprints so that it is easier for DIYers to install them. I used a multi-LED taillight in my 1968 midget for ~5 years before replacing them with 3W single-LED versions, both just involved plugging the new bulb in instead of the regular one. They had current regulators built-in. Oh, and the old, non-high-power LEDs also have polarity & current drive requirements so there is nothing additional that the high-brightness LEDs add except for the need for additional heat-sinking since the power dissipation is now centered on a single LED vs. multiple ones.

To address the original question, there is nothing that inhibits creating an LED replacement which fits into the original socket. If there was a big enough market, people would make them. Unfortunately there isn't, and it's definitely easier to make something outside the 1156/1157 footprint so that the electronics don't have to be so small. It's certainly a lot easier for the DIYer.

I've been designing my own caving headlamps with high-power LEDs for >8 years now so I do have some experience with these things... I'm also an EE who designs integrated circuits for a living.

Scott
Scott Linn

Scott, to answer your first question, I was using negative ground 1157 bulb on a negative ground system, so that was NOT the problem. I believe the 1157 housing & bulb base were poorly enough machined to allow shorting - which is what was happening.

To be very specific, the housing had three bent copper "tongues" two next to each other under the bulb, and one on the side for the ground. They were all old enough and worn enough that they could wiggle enough to touch each other just by turning the bulb in the socket.

As the MG housings are equally not works of engineering exactitude, I continue to believe that I should not offer a product made for that base. Others can. A more modern bulb and socket made say in the sixties or seventies would no doubt be better made, with less 'slop' - and hence less problematic.

In response to your other points.
Older low power LEDs come in two flavors; some are polarity specific, some are not. Hence, I've been able to install multiple LED lights on the dashboard of my positive ground TD without difficulty. As you move from 3mm to 5mm and up to SMT LEDs (surface mount, higher power) their design requirements make them polarity specific.

It is my understanding that low power LEDs may well have minimum and maximum current drive requirements but they as far as I know do not have critical constant current requirements (ie must operate at 350ma precisely but can run on anything from 5-28v, as mine do).

I have used 1157 LED 3watt versions successfully; it was (as I mentioned earlier) the 5watt versions that failed.

You may be right, it might be perfectly safe to use 1157 bulb bases in building my LEDs, which would make installation a little easier for the DIY. But I'm not going to do it. Using my current configuration, I believe i could build something that could utilize the existing 1157 socket, within the space confines of the rear taillamp. But I'd rather have the user remove the 1157 bracket, replace with mine, and screw in two wires and connect the bullet connector with the third. I'll warranty that. I look at the spring-loaded bent brass wires that hold the wires in place at the back of the MG 1157 bracket and think that that's one area where a slightly too-long wire could cause a short; the springloaded bullets inside the base of the 1157 socket, if crushed or bent or broken, could also cause shorting... the list goes on. Given the expense of these bulbs, I just don't want to deal with irate customers who popped in their 1157 base LEDs, twisted, and were were rewarded with instant smoke and no lighting... an experience that I have shared, as described above.

Anybody ever popped in a filament bulb and had it blow immediately? Not such a big deal with a cheap NAPA store bought filament bulb.

With a high power LED costing $50 and up... I want a little more security.

I appreciate your experience and knowledge with these issues. But you haven't yet convinced me to do this in an 1157 base on a 59 year old car with 59 year old wiring and 59 year old electrical design.

I'm opting for the safest possible route.

Lastly, I defer to your expertise when it comes to electrical engineering, and apologize for using vague terms like 'stray voltage'. Not being so familiar with the correct engineering terms for all these things probably makes my descriptions sound vague and inaccurate. But that doesn't mean that I am not building a great product - and I plan on offering it in the safest, most durable possible configuration, in the safest, most durable possible way.

Thanks for the conversation, it has helped clarify many things!
Geoff Baker

Hi Geoff:
Like James above, with the 53D's the 54 &55 F's have the round plinyth, for the rear lights. I too would like a set of these that would replace the entire spring loaded base. Mine would be the negative ground.
Would the replacement of the 2 rear lights with LED's and normal incandescent front wing lamps" have any impact on the flasher"?. Also If you are able to convert the front as well, so that all four are LED would this necessitate a change in the flasher?
Regards
Rod Murray
Rod Murray

Hi Rod, I'm working on the front bulbs right now.

Currently, using two rear LEDs has not necessitated any change to the flasher. I'll let you know what effect changing the front two lights has on the system.

Question, do you have the top red lens on your front market lights? My 51 TD does not, so I'm going to need to figure out whether to add an extra low power LED to illuminate that red lens.
Geoff Baker

Hi Geoff:
A very good point..... all of us with the red dot lens on the top of the wing lurn lights would have this issue:)
Regards
RodM
Rod Murray

"Older low power LEDs come in two flavors; some are polarity specific, some are not."

You might be referring to LED replacement bulbs. One can make LED replacement "bulbs" by putting a full bridge rectifier inside the housing with the circuitry and make external polarity unimportant, however that makes it a bit more expensive.

But, your statement that "(some) low power LEDs aren't polarity specific" is flat out wrong. LED stands for Light Emitting Diode. A diode is a rectifier; it allows current in only one direction. By definition, an LED by itself is polarity specific, regardless if it's a high-power LED or low-power. Some high-power LEDs (like the 5W Luxeon by Lumileds) actually had another diode in parallel, reverse wired, for ESD protection, but that's another story...

I have seen a lot of incorrect/misleading/bad information get propagated on the internet which is why I'm posting.
Scott Linn

Not trying to be critical of any advanced technology, but why would I change my tail lights, parking/turn signal lights to leds when they work fine as they are and are very bright? I'll grant you the dash/instrument lights could be a little brighter, (old eyes you know), but all the other lights, including my head lights are very sufficient, so why should I deviate from the original lights and change them? I found out when restoring the wifes 72 MGB, new original type wiring and connectors make a world of difference in lightning brightness. PJ
Paul Jennings

I’m addressing this to those of you who seem to know what you’re doing. Unfortunately, I don’t have a clue about what is going on here. Despite being an EE like Scott, my engineering days harken back to the early 1950s when computers were research devices with tubes, telephone relays and mercury-wetted relays; and what we hold in our hand today, took a room to fill 60 years ago. I do know what a full bridge rectifier is and some basic circuitry, but that’s it!

But here’s the issue. Today, most drivers drive much faster and closer to the car in front, than 20 years ago. I love to drive my TF at nights, but I’m terrified of having inadequate rear lighting, so I share Rod Murray’s approach. I want GOOD rear lighting and am less concerned about what’s in the little lamps in the wings.

Ideally, I would like nice, bright, reliable LED lamp I can simply plunk into the 1157 socket in my + grnd TF. If it means switching polarity, then so be it. I’ve been fighting that for 25 years. Maybe the time has come. But I don’t want to fuss with adding external circuits with Zener diodes, tape, clamps, etc. Just make it simple.

So I’ll be watching this forum, because its exactly where I want to go. Now, if someone will just steer me.

Gord Clark
Rockburn, Qué.
Gordon A Clark

Scott, yes, I was referring to replacement bulbs; they were screw in, non-polarity specific LED bulbs, quite cheap.

Paul, I'm glad you feel your lamps are sufficiently bright. And if you are happy with them, why change them?

I would add that your solution to your wife's MGB... replacing the original wiring... would undoubtedly make a difference, new wiring will conduct more efficiently than old, aged wiring and connectors! I would merely point out that that's probably the absolutely very most expensive and labor intensive way to upgrade your lighting, however.

I got into this for one reason; I thought my 51 rear rectangular lamps were WOEFULLY inadequate compared to modern lighting. And as Gordon points out, everyone is driving faster too, adding to the danger.

Look at any car today. Not only are they legally mandated now to have 50% more brake lighting (3rd brake lamp) but most of the brake lamps take up FAR more space and put out far more light than a 51 housing. I was sitting behind a new Honda CRV and noted that it appeared to have two brake housing lamps on both sides as well as separate running light housings as well as a 3rd brake lamp, and EACH housing was probably three times the square area of one of my 51 MG lamps! Add to that that the large, highly reflective housing surfaces and computer designed fresnel outer housings all transmit more light and transmit it to the right places... MUCH better than anything 50 years ago.

I know that I feel like my 51 MG's tail lighting is extremly easy to NOT see, that's all. And anything that improves on it without altering the original wiring and housings is, by definition, GOOD.

Ultimately, I think I will add a 3rd brake light mounted as high as I can, to complete the system. Now, it still won't be as bright or as visible as a modern car's... but it will be a significant improvement.

This didn't start out as a commercial product, it started out as a personal experiment to see what I could do to solve what I perceive as a safety issue, that's all.

For those who feel safe already... well, that's great.

At this point, I'm merely responding to interest generated by the many members on this board that have responded to these threads, either publicly or via email. And the pictures I've posted speak for themselves; the LEDs are brighter, period.

For everyone else, there are many solutions. Upgrade your wiring. Try different bulbs. Add 3rd brake lights.

Or just enjoy driving your car just the way it is... nothing wrong with that either!



Geoff Baker

Hi Geoff: In addition, to the potential "kits", for the round plinyth (used on 53 D's and all F's); if you are going to make a kit for 2 additional higher lights, I would like to order those as well! This is one safety area that I say "To Blazes" with the concours police:) I want to be SEEN!
Many thanks!
Rod Murray
Rod Murray

There are quite a few approaches using available components,see http://www.ttalk.info/led_high_mounts.htm
for a LED approach.
or, http://www.ttalk.info/Tech/HighMountLights.html for a very bright, can't miss seeing them, incandescent approach.

Be careful of the word brightness. It has virtually nothing to do with the quantity of light being emitted.

Bud (retired electro-optics engineer, from Gordon's era)
Bud Krueger

This thread was discussed between 08/05/2010 and 19/05/2010

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