LED headlight bulbs?

[Tony Fearn]

My pre-war Jowetts have 12v 36 watt, single pole old style bulbs in their headlights.
As I know nothing about LED lights, I just thought someone might be able to comment on whether it's possible to convert the old style ones to LED bulbs.
Will this be detrimental to a dynamo-driven electrical system, or could I go down this road?
Would the dipping system still work?
What are the pros and cons?
Tony

[Keith Clements]

Double check but I do not think LED bulbs in headlights are yet legal for old cars.
The main issues if they are will he focus of the beam, availability of positive earth, power of the light, heat dissipation from what will be a large cooling fin, and size .

[ajackson]

Tony
As of this year it is indeed legal to use LED headlamps in pre-1986 cars as explained here:

https://www.gov.uk/government/publicati ... onversions

Andy

[k. rogers]

I'm not even sure they're available, they certainly weren't when I enquired a couple of years ago. However, they are available for the side and rear/brake lights.

[Keith Clements]

The English in the regulation is ambiguous as it can be read as 'a conversion prior to 1986' rather than 'a conversion done on a vehicle that was manufactured prior to 1986.'
Hey ho another earning for the lawyers.

Halogen are much cheaper and give more lumens, plus they focus properly. There will be a reduction in amps, perhaps a fifth, required per lumen which might be the only reason for wanting the hassel. Fitting LED on all other bulbs should save enough to keep the amps low enough for the dynamo.
If you can, fit a Dynamator to give you more amps.

LEDs also contain rare earths so may not be quite so good for the planet as people think.

[Tony Fearn]

Keith, Andy and Ken.
Thanks for the quick reply.
I will go away and contemplate.
I was just trying to lessen the load amperage-wise, so that the dynamo wouldn't have such work to do when all the lights are on.
As I'm not doing the mileage as of yore, perhaps I'll just leave it all as it is.
I appreciate your help.
Tony.

[Keith Clements]

Read this first.
https://www.autobulbsdirect.co.uk/blog/ ... brightest/
and then
https://www.autobulbsdirect.co.uk/h7-ph ... -pair.html
Is it worth it?

[Tony Fearn]

Thanks Keith.
Well that sorts it out.
I'll leave it as it is.
At least with the F1/F2 positions on the PLC switch I get more amps in position 2 to accommodate the headlight drain.
There's also a moveable 3rd brush on the dynamo which you can set to give more or less amps.
In the past, (early 1930s) the way Jowett and probably other car manufacturers overcame blinding on-coming traffic was to use the dip switch
on the horn assembly in the centre of the steering wheel.
On full beam, both headlights shone on the road ahead wherever you had positioned them with the nuts underneath the front wings.
In the dipped position, the off-side head light went out, and a solenoid in the near-side pulled the reflector down and left a little so as not to blind an oncoming driver, but taking about 8 amps to do this.
I remember that some members changed this to bi-filament bulbs which of course had the dipping mechanism built in. This is beyond my capabilities.
Lastly, the sockets take single pole BA15s type bulbs.
As you can see, thanks to everyone concerned, and as I said before 'I'll leave it as it is'.
QED.
Tony.

[Keith Clements]

I would suggest fitting an easily detachable fog and spot lamp which can be switched on when required. This could be fed from a separate battery. On one Monte Carlo in the Javelin when our dynamo failed we drove through half the night on a torch, the remaining charge in the battery just had enough to keep the ignition working for 3 hours. We also followed other rally cars to conserve the torch. Eventually fell into a ditch. We were pulled out and made it to a rest halt where I borrowed a spare alternator off a fellow mini competitor and changed the Jav wiring to get us going.