Battery not charging

[Mick D]

Hi Bruce

That's positive, (no pun intended). Do you have a multi meter, or can you borrow one? Set it to Volts DC and connect it to the battery terminals, (red to positive), it should read six volts or slightly less when the lights are on and engine off. With the lights on and the engine revving slightly it should read over six volts, if this is so then all seems OK. If, with the engine running the battery reads below six then you probably need to investigate the regulator, please report back again.

Regards Mick

[BruceWatts]

So, here is the state of play, which is giving me sleepless night !!
With the engine running and revs high, the voltage across the battery does not go above 6 volts. Furthermore, the lights do not brighten either.
I have once again tested the dyno, by bridging out the terminals and measuring the voltage to earth. It is way above 6 volts depending on the revs, so all seems to be good there.
First question.
Which of those terminals on the dyno are for the "F" and "D" wires to the regulator, ie is the lower one or higher one "F". Does it not matter?
I have replaced to regulator with a "new" one I bought several years ago. It was still in it's box. How can I test it. Making sure that the "F" and "D" wires are well connected, can I test the output from the "A" terminal, which appears to be one one carrying the current to the lighting switch, for distribution to the ammeter and back to the battery?
In my limited electrical knowledge, I am trying to following the flow of the current, testing each part, to hopefully find the fault. A bit like canoeing down a river trying to find the beaver dam !!!!

[Mick D]

Hi

It does matter which way you connect F and D, I'm not sure which type of dynamo you have but the Brightsparks website has a good online Lucas library so you can look it up for yourself. See what happens when you are sure F and D are correctly connected, who is the regulator manufacturer?

https://library.brightsparkmagnetos.com ... /index.htm

Regards Mick

[Chris Sealy]

The voltage on the D wire, which is the lower terminal, is the dynamos output voltage. It splits into two; one wire goes to the ammeter, the other goes to the regulator.
Initially D is connected directly to F; which is the upper terminal; by a closed contact, inside the regulator.
If you connect a voltmeter between D or F, and any bare metal on the engine, you should get exactly the same result as connecting a piece of wire between D and F.
Let us know what happens.