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Bulbs specifications and conversion to LED

PostPosted: Mon Jul 09, 2018 6:40 am
by LotusEngineeringBuff
I am happily driving my Plus2 after x years of storage and 1 1/2 year of resto/reconditioning. It got a fresh Swiss MOT and I am now in the shake down period I would say. One of the remaining problem is that the headlights thermal cut-off switch fires after 10-15 minutes. I found it kind of funny the 1st time because it was not pitch dark and I was on a quiet road. But not so last week when I was with passengers (2!) on the highway.
I did not want to go back to rewiring the additional large section wire across the engine bay and relay so I thought LED.
Being on this track, I thought I might as well do a full LED conversion. The document attached could save you the time it took me to put the information together in case you want to go that route too.

I'll let you know in August how things are working

A) The links for the LED procurement will soon be outdated because this market is evolving very rapidly
B) I know that I might not be legal presently to have LED headlights. Law is slow to adapt. I do not doubt that in the close future it will. And if its not, I'll just revert to std H4 for MOT testing when the time comes.

Until then have a nice summer


Re: Bulbs specifications and conversion to LED

PostPosted: Mon Jul 09, 2018 7:30 am
by gherlt
I have doing research on this for my two seater and bought two led 7" headlamp sets, both advertised as "legal". Both are sold mainly for land rover defender.
One is from eBay UK, seller originalcaferacer. It has an ECE marking, but in Germany MOT/T?V told me, to be considered legal they are missing the allowed use (some letters) and the certificate numbers, usually 5 digits.
Otherwise good looking, well made, perfect fitting, good light. Beam is a bit strange. I'm original position the beam is a wide angle \/, not as it should be (lhd _/ , rhd \_). Answer was "turn it a bit" if I understand correctly.

The other one is from truck lite, they have the markings, so should be legal. ... reId=10001

But ... Not sure how tell this, the glass is far more forward from mounting ring than the normal headlamp. Fits perfectly, but glass blocks closing movement of the bowl. No chance. Also a bit heavy.

There a few more headlamps, but the looks are too modern.

Re: Bulbs specifications and conversion to LED

PostPosted: Mon Jul 09, 2018 1:44 pm
by Frogelan
I'm rebuilding a 1965 S1/2 from boxes, E**y...and the 3 main firms for Elans.

When looking at the headlamp situation (LHD / for EC compliance), I decided that none of the LED possibilities are close enough to being EC road legal for headlamps. This is echoed by any serious vendor with possibly one exception (RHD and LHD): ... -headlight

This exception is expensive, but the vendor is very helpful.

As I wish to be able to rally/race within a FIA context, I have opted for new Cibi? 5 3/4" units (for 26R type lamps) with Philips uprated H4 (EC legal) bulbs. I have not yet tried this combination. (The Cibi? units are very expensive in Britain, but good value in France if you have the patience to look (I bought mine from

I also plan to mount PIAA HID 140mm spot lamps for racing / rallying placed within the front air intake and mounted "cross-eyed". These are very effective as a supplementary source of light (I used to ahve them mounted on my MGB...behind the front grille!). These are not necessarily FIA acceptable, but scrutineers are more understanding if these are discreetly mounted.

For all of the other LED bulbs, I bought these from A great deal of patience is needed on this website to find the right bulbs (for F & R indicators, brake lamps, side lights).

I'm happy to pass on the references if it would help but owner Gil Keane may remember my order as we had a good natter.


Re: Bulbs specifications and conversion to LED

PostPosted: Mon Jul 09, 2018 3:52 pm
by prezoom
I had a similar problem with the thermal switch on my Plus2. What I found was, the spade connector on the output side of the switch was quite loose, thus causing a high resistance connection, which in turn caused the switch to operate. A healthy squeeze with pliers tightened the connector to the point that it was difficult to re-connect. No problems since. It was a first attempt solution. If there had been more room under the dash, I would have replaced the connector and the insulating cover, which was also severely heat damaged. As a replacement for the cover, I used a double layer of heat shrink material.

Re: Bulbs specifications and conversion to LED

PostPosted: Mon Jul 09, 2018 4:44 pm
by elanfan1
Might I suggest it would be a good idea to add the bulb pdf and other useful LED stuff to this threa? in order to attemp5 to keep it one easily searchable thread?


Re: Bulbs specifications and conversion to LED

PostPosted: Tue Jul 10, 2018 9:08 am
by LotusEngineeringBuff
You are right. I did not find this thread before writing my post. I will add more info to my sheet (like luminous values in Lumen, since Watts are not meaningful to compare filament lamps (i.e regular) with gas discharge lamps like Xenon or LEDs) and re-post where you suggest.

Re: Bulbs specifications and conversion to LED

PostPosted: Tue Jul 10, 2018 4:30 pm
by denicholls2
An important consideration for the bulbs used in turn signals and flashers is that the original flashers are mechanical (bimetallic strip). LED bulbs will not draw sufficient current to heat the strip and make the bulbs flash, so the flasher relays must be replaced with electronic versions (and these must not be current-sensing either, as many aftermarket items are.)

For the U.S., I doubt anyone will look close enough for compliance (an inspection here consists of seeing if the bulbs work and occasionally if they are aimed properly.) Lowering the current draw for the high-amperage items like headlamps is a good safety move and simpler than adding relays. Digging out the lamps is also a good opportunity to add or renew dielectric grease on the Prince of Darkness' connectors. The unobtainium indicator switches will also last longer without high current draw.

Re: Bulbs specifications and conversion to LED

PostPosted: Sat Jul 14, 2018 7:56 am
by bob_rich

LED bulbs look interesting. Looking at the headlamp bulbs I would see if you could get a drawing of the overall size
the electronics that power the LED's seems to be housed in the alloy heatsink at the rear of the "bulb" I would check that the depth of this still permits it to fit ok in the pop up headlamp pod of the Elans and +2

also how is the electrical connection made to the LED bulb this may further increase the depth requirement

hope this helps best of luck


Re: Bulbs specifications and conversion to LED

PostPosted: Sat Nov 17, 2018 8:48 am
by LotusEngineeringBuff
A quick update on the situation. I have now converted all bulbs to LED apart the ones on the dash (warning lamps and night ligthing).
I have now a problem some of you anticipated: The flashers (indicators and hazard lights) do not work any more! I have ordered, received and bench tested 2 types of flashers (2-connectors and 3 -connectors) and they are ready to be installed. The small problem I that I cannot find where there relays are located. I will put the filament lamps back in to have the original relay flash so I can hear wehre they are!!!

Here are the link to the electronic relays (no commercial interest, but since I live in Switzerland, I have no local provider and shipping from the UK is very expensive) ... 35234.html ... 11446.html

MORE IMPORTANTLY: As far as the main lights are concerned, it seems the LED "bulbs" I got are not usable. The short beam, excuse my English, is ok, very bright and possibly a bit high which I can correct with the adjustment screws. But the high beam is much too high. The way these bulb work is that in short beam position 2 LEDs are turned on on the bottom left and the bottom right of the triangular rod that replaces the original glass bulb. These 2 LED are more or less where the original filament is located. In long beam position, these LED remain ON meaning the lighting on the road is the same, and an additional LED on top of the triangle turns ON. That one produced a round spot so much higher that the two others that it does not even blends with the illumination pattern of the 2 other LED. I still have to test that on the road but I expect I will illuminate the tree tops.

I will send you a pic of the illumination pattern on the hangar wall soon.

Re: Bulbs specifications and conversion to LED

PostPosted: Mon Aug 19, 2019 8:11 pm
by LotusEngineeringBuff
For months the Plus 2 has now been fitted with LED's all around and electronic relays for the flashers. Everything works fine, but...
I confirm that the H4 I bought are hardly usable. The "bulb" is in 2 parts. There is one base plate that matches the original collar with the 3 prongs to locate to bulb and there is a shaft with the LED's in front and the fan at the back. The shaft goes in the base plate where is locks with 2 tiny prongs. One of these prongs has already broken and the shaft is not safely located.
Plus the difference in height between long and short beam is just too large to be able to set both correctly
i'll try to source a set correctly designed

Re: Bulbs specifications and conversion to LED

PostPosted: Tue Aug 20, 2019 5:51 am
by Frogelan
Bonjour Francois

My project is still a I have not done any testing. So this is what I have learnt so far...

- after market LEDs often need very careful handling: I have already broken one unit just "handling it" and suspect that that in some cases they are not robust enough for automotive use...I bought mine from "bettercarlighting". I offer no particular recommendation as I have not tested them!
- I have adapted rubber seals from other lamps to ensure better sealing and protection from vibration and water ingress. I will also use transparent sealant and put heatwrap on the wiring.
- a special indicator "relay" is needed
- items such as headlamps are going to inevitably attract the attention of either technical testers (Contr?le technique, MoT etc) or the Police if LEDs have been used. An insurance assessor may not like the idea either...
- H4 Headlamps lack "type approval" for LEDs and therefore it is probably wiser to only fit ECE approved H4 bulbs. Philips have a ECE range of powerful (the packet says so...) bulbs!
- For my S2 which will have oval series 2 26R headlamp covers (sort of road legal...) that I hope to use both for road, rallies and track I'm fairly certain the headlamps (Cibie H4) will be rather limited by the bodywork so I will use additional PIAA long distance lamps set within the "mouth" (130mm dia) and low mounted Cibi? 35 fog lamps (jaune, naturellement!).

I hope this helps!

Re: Bulbs specifications and conversion to LED

PostPosted: Wed May 06, 2020 2:07 pm
by TBG
I now have 100% leds throughout and the difference is quite amazing. The MOT tester said that the sidelight bulbs were brighter that some headlights he had seen! Bit of an exaggeration there I think! But the sidelights are now wonderfully bright as are the brake and indicators. As regards robustness I have not had a problem

It is sometime now since anyone commented on LEDs and things have moved on. Any new comments out there?

Is it possible to load videos so you can see the difference?
Spot indicator.jpg and