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LED replacement bulbs for rear lamps


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Having tried out a number of different offerings to replace the 6 / 21 W bulb used as stop /tail (TR3a,3b) or indicator / tail (TR2,3) None of them actually outshone the original bulbs. The problem being that the position of the LEDS was not in the correct place within the plastic (or glass for early TR2's) covers. There is a Fresnel lens built into both these covers, & the original bulb filaments are placed at the focus of these lenses to give a good intensity when viewed from behind.

So, I decided to make my own version. many types of LED chip were tried, mostly white in colour as I could not find any red ones which were bright enough, The basic design places 3 X white LED chips (or 4 X red ones) at the focus of the lens, & they worked well enough, comparison tests between standard bulb & my units showing a definite improvement.

The final breakthrough was following a meeting with fellow Forumite Dave Lacey, who was interested in my project, & sent me some high power red led's which his company used for a different purpose.

The improvement these offered led me to design & have made a number of printed circuit boards to take these led's & supporting components. These boards are assembled, then mounted, & potted into the standard bulb base.

I have now installed my TR, a friends TR, both with the Lucas L549 lamps, & my Hillman Aerominx which has the L741 lamp unit (same as early TR2's). They can be configured for 12V or 6V working, also -ve or +ve earth. I have now made up a total of 8 "bulbs", with another 12 assembled pcb's but not yet configured, or mounted to bases.

 

If anyone would like to convert to these "bulbs" I can supply them ready to go, but as they are hand assembled numbers are limited, & they may take a few days to complete. Cost would be £10 per bulb.

Note. if using on a TR2 or TR3 with no separate amber rear indicators then a different flasher unit will be required as with any LED conversion, these are readily available from a number of suppliers, I used one from Gil at "Better car lighting".

 

Imaged attached shown comparison with standard bulbs, LED on left, bulb on right

 

post-12009-0-66575800-1485433361_thumb.jpg post-12009-0-07071300-1485433363_thumb.jpg post-12009-0-39012900-1485433364_thumb.jpg post-12009-0-46061200-1485433365_thumb.jpg post-12009-0-60519300-1486566686_thumb.jpg post-12009-0-33493600-1486566685_thumb.jpg post-12009-0-96730200-1486566685_thumb.jpg

 

Bob.

Edited by Lebro
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Roger.

 

I know what you mean. I can make the tail part as dim as you want, The tail lamp on any new ones will actually be a bit dimmer than the examples above.

 

It's only a case of changing one resistor. The Stop lamp brightness is as bright as I felt happy with regarding heat dissipation of the components.

The LED's are running at 0.4A (stop lamp mode), & 0.08A (tail lamp mode) They are specified to run at 1.0A max continuous, & 2.5A peak !!

 

 

Bob.

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Stuart.

It's not just the LED's which get hot, the resistors feeding them also have to dissipate heat. It all a compromise between getting as much light as you can, & keeping the design practical. More heat generated means you either have to make everything bigger to be able to dissipate it, or accept that everything on the board will get hotter, & may fail because of this. A good rule of thumb is if you can keep your finger on a component, then it's not too hot. !

These LEDs & resistors pass that test, but they do get warm - especially if you sit with your foot on the brake for long periods !

 

Bob.

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They look good Bob. I switched my tail/brake lights over to LEDs middle of last year and was pleased with the result. However, since doing that I've heard tell that if the car wasn't originally intended to have LED lights it may fail the MOT on that basis. I've not had an MOT since fitting mine, but it has been playing on my mind whether I need to change back to the original bulbs ready for the next MOT in April. It does seem crazy if this is the case, because good LED bulbs seem much safer. Anyone know the current situation with the MOT and LED bulbs?

 

Cheers, Darren

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Hi Darren,

don't panic. The MOT man would need to see the LEDs before he would do anything.

The headlights would be a different matter as they can easily be identified.

 

As long as the tail/brake lights had the correct intensity then all should be well.

 

Roger

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FWIW, I think insurance would only be a problem if it is discovered that one (or more) of the NON ORIGINAL bulbs had failed, thus causing the accident.

LED type have a much longer life than incandescent bulbs, but still worth checking them regularly.

 

I dare say that the insurance companies would play up even if an original type bulb was found to be failed after an accident.

 

Following all these posts I should add that anyone using "my" replacement bulbs does so at their own risk.

 

Bob.

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There can't be many side screen cars which still require an MOT.

Regardless of that they still should be submitted for one!

Stuart.

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All those who requested some of these - they will go out in todays post.

Please let me know when you receive them, & how you get on with fitting. Ta.

 

Bob.

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Bobs LED rear bulbs make a tremendous difference see pics on my + earth 3A

 

LED Nearside Original bulb Offside:

 

Side Lights:

 

_MEA3475_zpsq8bxjd0l.jpg

 

 

Brake Lights:

 

_MEA3478_zpscaslzjcp.jpg

 

Side and Brake lights:

 

_MEA3480_zpsy4wzd4lj.jpg

 

A marked improvement and IMHO make driving a side-screen TR on the roads a great deal safer

Edited by Paul Down
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Yes, Bury indeed.

 

The car originally had competition extras and was apparently yellow, Alec remembers the car at Hill climbs etc but an advert in the local press did not reveal the owner.

 

If anyone can provide any info that would be most helpful.

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Have just fitted and tested these LED's. They are Excellent.

Great improvement in clarity and good contrast between side light and brake light brightness.

Bob has taken great care with these to ensure the LED's are absolutely at the correct angle for the rear light lens.

 

I wont feel quite as vulnerable as I did driving to Harrogate in that Monsoon a few years back....

 

Lets hope MR MOT man likes them too. :D

 

Iain

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So THAT' S where LEN 898 has ended up.....often wondered, as I knew Dave Tabb, who rebuilt it very nicely, had sold it some years ago. I sold it to Dave circa 1999--I'd found it in the basement of a country garage near Corwen in N Wales, covered in dust and exceedingly scruffy, but complete and with a number of competition parts fitted, indicating it had been something special....always wondered if 1960's rallyman Don Grimshaw was connected to it, as I believe he was a Bury man. When I found it it had been dumped at this garage for many years and it was said to have belonged to a murderer doing life somewhere, who had left it there for repairs and not surprisingly, had been unable to pay or collect ! Another story for "Kerbside Motors" when I finally get round to writing it ....... Bill P.

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To get this thread back on course:

On Sunday I fitted up the two LEDs that I ordered from Lebrero, to my 3A. The result is impressive and yes there is a marked distinction from the brake lights whilst braking with the tail lights on.

I feel that they are a major contribution to safety and begin to compete with moderns. In traffic the rear of the TR now begins to light up like the guy in front.

As RogerH has said, the MOT man is unlikely to look to see what you have as long as it works. Here in France the MOT is more concerned with safety than originality when they check our kind of vehicule

I have an agreed value insurance inspection coming up so will ask Monsieur what he has to say.

 

James

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