Classic Dynamo & Regulator Conversions

January 2023

A word of advice if you are thinking of buying LED bulbs and associated products for your cars or motorcycles. As time has gone by, the market has become flooded with some very cheap and dubious products.

People are 'jumping on the bandwagon' so to speak and some of these people, it appears, haven't a clue what they're selling and aren't doing it for the satisfaction of supplying a product that does what you expect it to, but to make their money selling inferior items.

My advice is this - Be careful when buying! Many of these products use out-of-date technology. Others might not do what you expect them to do or look right when fitted to your classic. We have a habit of checking the market and buying in 'samples' to test and the results are not always good.

'All that glitters, is not gold' as the saying goes.

Many products are mass produced and others have obviously been made without 'on the vehicle' testing for purpose.
What looks nice and tests well on a bench, may not look good or indeed function well when fitted to your vehicle. As we all know, older vehicles can be a problem with bad earthing etc.

We at CDRC Ltd, were the inovators of LED products for vintage and classic cars and bikes and our policy has always been to offer you the best, and, using the latest tecnology. We know old car electrics through and through. 
Believe me - LED technologhy has come a LONG way in the last few years as car manufacturers use it in production vehicles more and more. 
Some of us do our homework and keep up with the technology to ensure you get a tried and tested product, tested in an old vehicle, not just on a bench power supply. 

We constantly monitor the market and it's easy to see those that just sell what's offered rather than what's properly tailored to suit. 
I honestly find it unbelievable when I see what some people are offering.

Be careful where you spend your money. Any specialist will know what they are selling.  We have an active role in the design and testing of all the products we offer. After all, we started the ball rolling all those years ago. 

We've been offered products by manufacturers that look nice but after testing, we find that they are not actually fit for purpose so we turn them down. We will not offer you a product that does not pass our stringent testing and we certainly will not sell a product on the manufacturers word alone.

For example - All our headlamp bulbs will pass a UK MOT test when fitted to a pre 1986 vehicle. They all have a great beam pattern.
Our Double Dipper Pro range are all colour 4300k for that classic look. Our BA21d Marchal bulk is colour 3000k for that authentic yellow look on French cars and bikes.

So, the moral of this story is this - Shop wisely and shop with a company that knows the market and knows what you want, a company that is run by enthusiastic people that own and run old cars and bikes themselves 

For LED headlamp bulb hints and tips click HERE

I thought I'd write this page to benefit those that may be experiencing problems when fitting LED bulbs and light boards.

Just so you know that it's not a faulty bulb.

So, you fit nice new low power consumption LED bulbs or light boards and they don't all work but the original filament bulbs did.

For example, you've fitted our stop/tail bulbs or light boards.

The stop lights work fine but the tail lights won't work at all.

Or the stop light won't work with the tail lights on.

If you test the LED bulbs on a battery they work fine?

This points directly to a simple vehicle wiring problem that wouldn't have shown up with filament bulbs and is actually to your advantage to fix as it means your wiring will be as originally intended.

First and foremost, where combined stop/tail bulbs are concerned, fit both bulbs before testing. Fit one and you may find it won't work. Fit the other and they will both work.

Still got issues??? It'll be a bad earth somewhere in that circuit or one or more lamp is wired the wrong polarity

This problem tends to show up more with lampholders that are insulated from the vehicle or where the number plate lamp is separate to the stop/tail lamps

A cruddy earth connector can restrict the passage of current and because LEDs use so little current a cruddy connection can mean no connection.

LEDs are all polarity conscious. Our bi polarity LEDs work with either positive or negative earth but every bulb on a particular circuit MUST be connected the same polarity or one will conflict against the rest and result in problems. Dedicated positive or negative earth bulbs work on the same in theory.

For example - A positive earth vehicle has 2 Lucas stop/tail lamps with our bi polarity or positive earth stop/tail LED bulbs fitted. The number plate lamp is separate and is connected to one of the tail lamps so that it comes on with the tail lamps. The vehicle being positive earth means the positive feed goes to the cap of the stop/tail bulbs not the terminals. The feed to the number plate lamp must be the same i.e. positive from the cap of the stop/tail bulb MUST be connected to the cap of the number plate bulb holder(s).

A customer complained that neither my bi polarity or dedicated positive earth LED bulbs would work properly on his positive earth Fordson van. Stop lamps were fine but the tail lamps wouldn't work at all. If he fitted the original bulbs, all was well. The vehicle was freshly restored and fitted a dynamo that I had rebuilt and a regulator that I'd converted to 6v positive earth electronic. It had restored lamps and a new wiring harness. Everything worked as it should bar the tail lamps.

On investigation, the tail lamps were wired positive earth but the separate number plate lamp had been connected for negative earth. Simply swapping the 2 wires around on the number plate light cured the problem.

LED bulbs can fight against filament bulbs on the same circuit so if you change your stop/tail bulbs you may need to change sidelight bulbs too.

Treat LED bulbs like small children - Whatever you give one you must give exactly the same to the rest or there'll be conflict!

The same goes for flashing indicators, pilot lamps, side lamps, dash lamps etc.