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What is an Electronic Dynamo Regulator Conversion

 and why would my vehicle really benefit from having one???

Take the time to read this page please

The most troublesome part in any old vehicles dynamo charging circuit is the antiquated mechanical cutout/regulator the cause of most charging problems. They never were very efficient even when new. As they wear with age and use their efficiency gets even lower. Please read on...........

Our "state of the art" electronic conversions are very efficient and reliable. Our regulators will never wear or need adjusting as they have no moving parts.

Continuous improvement over the past few years means they are now the best on the market and perfectly matched to a classic vehicles dynamo characteristics.

 They bring its charging system well and truly into the 21st century and give you much better lights and battery charging by replacing the mechanical internals inside your existing control box to keep everything looking nice and original .

So no matter what car, motorcycle, tractor or boat you own from the 1920's through to the 1970's, if it has a dynamo charging system, it will benefit greatly from a hidden electronic regulator.

On its own your dynamo is a rugged and reliable piece of equipment but needs two things for it to do its job.


1. A cutout device to disconnect it from the battery when its not working.

2. A regulator to control its output as engine speed increases/decreases.


Let's compare a mechanical unit with an

electronic unit.


Mechanical Cutouts and Regulators - The Facts


On old cars and motorcycles there have been two types of mechanical control device over the years.


A Typical Pre War Mechanical Cutout looks like this


First introduced around 1915, the cutout is an electro-magnetic switching device that breaks the circuit between battery and dynamo when the dynamo is stationary or turning too slow to produce a charge. You can see the switch contacts on the left (the black dot).  The fuses protect auxillary circuits and the dynamo field (F) circuit

Regulation of the dynamos current output is by a 3rd brush in the dynamo. With the most basic systems the battery got full charge all the time. Some, the charge could be switched on or off by the driver. Others had 2 coiled resistances fitted underneath the cutout. These resistances are switched in or out by the summer/winter switch on the vehicles dashboard to give a high or low rate of charge. They get hot when switched in. If you keep heating and cooling a wire resistance it gradually becomes more resistive so lowers the dynamos output more than it should to below an acceptable figure.

The vehicles battery is like a big resistor in circuit to maintain the voltage at somewhere around 12v. Topping up of the batteries electrolyte had to be done regularly as it was boiled off due to over charging. 

In the days when batteries were made of quality components and could be topped up over charging wasn't such a problem but with modern batteries that are generally made using much cheaper components and/or tend to be sealed, they boil off the electrolyte through their breather. This electrolyte can't be replaced due to the sealed maintenance-free nature of the battery and it soon dries up which with continued over charging, ruins it. I've known batteries swell up and split. Sulphuric acid everywhere. 

Sulphuric acid is highly corrosive.

This very basic method of cutout and regulation lasted until around 1936 when Lucas introduced the

Two brush dynamo and Compensated voltage control unit.


A Typical Lucas Mechanical Compensated Voltage Control looks like this.

  It's a cutout and regulating unit all in one case.

The cutout solenoid and switch is the one on the right.

The regulator is the solenoid and switch on the left.

The cutout side of things is exactly as it was in the pre war cutout.

The regulator works so fast that it vibrates, opening and closing a switch very quickly to regulate the voltage. It compensates for the current being used by allowing the dynamo to output the same amount of current.

Both the cutout and Compensated Voltage Control units are mechanical.

Mechanical moving parts wear and go out of adjustment.

The coils (solenoids) use valuable current to do their job, they go out of adjustment and the switching contacts burn and wear.

The CVC, again a very basic cutout with an as basic regulator mechanism stayed much the same  until around 1973 when dynamos were phased out in favour of  alternators.


The only improvement over all was the use of a 2 brush dynamo - a far more efficient machine.


To sum it all up.......

On most small pre and post war cars and motorcycles, the dynamo was only capable of producing about the same amount of  current that the vehicle would use to power its lights, coil and mechanical regulator so there is little or no spare current to power any extras.


To satisfy the modern MOT test we have to fit extra brake and rear lights. This puts extra load on the dynamo to the point where it cannot supply enough current.


This is why the ammeter needle shows a minus or

 discharge with the lights on even at speed. The vehicles lights etc are using more current than the dynamo can provide.

The extra current needed is therefore supplied by the battery  which will gradually flatten it.


During daytime running especially with a

Winter/Summer set up, the battery can receive too much charge. This results in the electrolite being boiled off and shortened battery life.


The post war CVC was better than this and a huge step forward in a way but had more moving parts to worry about.

The result is that sometimes they cut in and sometimes they don't.

Sometimes they cut in but don't cut out again and this is when things get hot, wiring melts and dynamos "cook"

Sometimes they regulate, sometimes they don't.

Over the years they wear and get fiddled with.

So if your ammeter's moving in and out of charge as you drive  or your battery light's flickering at speed, that's why! 


Technology has come a long way since 1973 let alone the 1920's!


Enter, the Electronic Dynamo Regulator 


Electronic regulators - The Facts


An electronic dynamo regulator is a piece of modern

technology that replaces any make of mechanical regulator or cutout used in a dynamo charging system on cars, motorcycles, tractors, boats, stand-by generating sets etc etc.


An electronic regulator looks like this when fitted into your vehicles original case.

Put the lid on and you'd never know it's there!


This example is a 12v item in a restored Lucas case ready for dispatch to a customer to start doing sterling service in a pre war MG.

The black capsule on top of the new regulator contains an inline fuse that protects the dynamo and the regulator. Current limiting circuitry also means your dynamo can only ever produce its safe maximum amout of current. This circuitry protects the dynamo's field circuit and armature from overload.

The conversion is very small, has no moving parts to wear or go out of adjustment and uses so little current it is barely noticable.

It uses ultra reliable Solid State switching technology so there's no switch contacts to burn, pit or stick together.

It allows the dynamo to charge at much lower speeds so is ideal for older low reving vehicles and for town work where a mechanical regulator would cut out and not charge.

It works even if the vehicles battery voltage is very low or if the battery is nearly flat.


They are are suitable for 6 and 12v positive and negative earth vehicles with two brush dynamos or a three brush dynamo properly converted to two brush.

Regulators for Siba and Bosch Dynastarts and vintage Dynamotors are 12v negative earth and suitable for two brush machines.

So if your vehicle has a primitive three brush dynamo/dynastarter we properly convert it to two brush and fit an electronic regulator.

If it's already a two brush machine and in good condition then we normally just fit an electronic regulator.

With negative earth you can connect modern equipment to you vehicles electrical system such as a cigar lighter to run a mobile phone charger, a sat nav an Mp3 or DVD player even a modern radio or cd player.

You can't do that with positive earthed vehicles.

(Click here for instructions on converting to negative earth)




So, in Conclusion.........


Connect a very basic, uneconomical, unreliable, worn mechanical regulator to your rugged, reliable dynamo and you're going to have dim lights and bad charging.

Connect an electronic regulator to your rugged, reliable dynamo and you have two rugged and reliable machines working together giving you the

Ultimate invisibly upgraded dynamo charging system 

Why not benefit from some modern maintenance free, fit and forget technology that will put an end to you charging problems and is hidden away to bring even the oldest dynamo charging system up to date???


The 10 benefits to you and your vehicle are.........


1- Brighter lights

2- Better low speed charging

3- Perfect charging with lights on or off 

4- Better starting

5- No more flat or low batteries

6- No more boiling of the battery

7- Longer battery life

8- Peace of Mind

9- Everything looks as original

10- Only YOU know its there


Ten good reasons why your vehicle needs one!


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