Stopped charging

[BSA500]

Hi,
 I have a 12 volt dynamo set up on my 1960 A7. One day charging fine the next not. Dynamo giving 20+ volts up to the regulator, but no charge on the ammeter. Ammeter shows discharge when lights on so I assume that works. Measured the output at the A connection and it's 3.3 volts. All earths/connections etc have been checked. I have sent a mail to Dynamo regulators for any info/help but this is way out of guarantee so not expecting a free replacement etc. Any thing I missed?. Also if they ask to test the reg would it be wise to disconnect the dynamo drive if I use the bike for work.As long as the battery is charged I only need brake lights.

[KiwiGF]

By A connection do you mean at the reg (brown wire) ? If so shouldn't that connection have battery voltage as a minimum, and say 13v plus when it's charging? Or did you measure it with it disconnected?

I'm assuming you've not had the battery out and put it back with connections reversed 

I'm not sure what voltage the brown wire would have when disconnected from a battery.  Maybe someone could measure a 12v reg set up to see?

I don't think any harm comes to dynamos that are spinning but not connected to a reg. they don't generate high voltages that could damage it etc.

It does sound like the reg is duff but it's probably worth cleaning the commutator as the armature can give a reasonable voltage from residual magnetism (particularly if you are using a very sensitive voltmeter), but despite that it's still not able to give enough current to get the Dynamo going due to dirty brushes etc

Flashing the Dynamo might also be worth a try.

[BSA500]

By A connection do you mean at the reg (brown wire) ? If so shouldn't that connection have battery voltage as a minimum, and say 13v plus when it's charging? Or did you measure it with it disconnected?

I'm assuming you've not had the battery out and put it back with connections reversed 

I'm not sure what voltage the brown wire would have when disconnected from a battery.  Maybe someone could measure a 12v reg set up to see?

I don't think any harm comes to dynamos that are spinning but not connected to a reg. they don't generate high voltages that could damage it etc.

It does sound like the reg is duff but it's probably worth cleaning the commutator as the armature can give a reasonable voltage from residual magnetism (particularly if you are using a very sensitive voltmeter), but despite that it's still not able to give enough current to get the Dynamo going due to dirty brushes etc

Flashing the Dynamo might also be worth a try.

I tested the brown wire disconnected as suggested on the Dynamoreg site. They state on the 12 volt setup I should see 14.2 volts. I know I have 20+ volts going into the reg. The dynamo was rebuilt in November by Priory magneto's as a 12 volt upgrade(the last rebuild was due to the D connection shorting not the 12 volt set up-somebody pinched the wire  ). The reg has been performing perfectly up to now. Commutator is still very clean. I see what you mean by current output but one day reg is fine next not

[KiwiGF]

In this extract from the web site below it says measure 14.2v with it all connected? I guess it might say somewhere else one can measure the 14.2v with it also disconnected? ( I know this sounds argumentative but I'm just trying to help). I'm actually in the middle of wiring up my b31 with a brand new dvr2 so have the instructions to hand, and will be doing these exact same checks very soon 


"Charging Checks
After the DVR2 has been connected check all connections one more time according to the diagram above. Make sure that the dynamo is well earthed (no paint or corrosion blocking the current path). Start the engine and slowly increase speed until a small charge is shown on he ammeter. If this is not seen at about one third maximum revs, stop and check again. It is a good idea to measure the regulator output voltage at A (other lead to earth E). The regulator output should stabilise at 7.2 or 14.2 Volts as the speed is increased. In normal operation only a slight 'trickle charge should be seen on the ammeter (about 1⁄2 to 1 amp). A high charging current shown for a long period may indicate a very low or faulty battery or other problem requiring attention."

[BSA500]

I sort of read that as reading from the A lead disconnected, but even connected no charge showing at the ammeter. I haven't measured across the battery but I would have to unmount the seat again. The lights do not brighten either when revved. Looks like a fubarred reg to me but I have asked the manufacturers for any input etc.

[BSA500]

Just spoke to Mick Hutchings at DYNOREGS and it seems likely the reg has gone south. He offered to test but taking into account the dynamo is putting out a strong volts and no changes to the wiring etc it would be wasted money on my part. From his records I purchased it in 2012 and since then they have been improved so prob best to go for a new one.

[Dynamo Regulators Mike]

To clarify; when correctly working the DVR2 and dynamo should show about 14.2 V with battery connected or not. The voltage will be a little less stable without battery as the battery characteristic 'damps down' any fluctuations.

it does appear that this DVR2 has failed, although it outlived a faulty dynamo, probably caused by overloading it with too powerful lamps.

I would be happy to test this regulator, free of charge (as it were), to confirm whether it is faulty as it seems, and if it is, to assess how it has failed.

Mike at Dynamo Regulators Ltd

[BSA500]

To clarify; when correctly working the DVR2 and dynamo should show about 14.2 V with battery connected or not. The voltage will be a little less stable without battery as the battery characteristic 'damps down' any fluctuations.

it does appear that this DVR2 has failed, although it outlived a faulty dynamo, probably caused by overloading it with too powerful lamps.

I would be happy to test this regulator, free of charge (as it were), to confirm whether it is faulty as it seems, and if it is, to assess how it has failed.

Mike at Dynamo Regulators Ltd

Thanks for your advice/help. I will order a new one but if you wish I can send you the old one so you can play with it(but if it test's ok don't tell me  ). Especially seeing as more improvements have been made to the current regulators against this one I bought in 2012. Maybe the years of pushing the dynamo somehow shortened the life of the reg?.

[muskrat]

I've had DVR2's on both my A's for years running 12 volt. The only time one failed was when a mate was helping me throw one back together. He put the battery in back to front.
Cheers

[BSA500]

Well I have put the new regulator in and realised two things one I may have cocked up and two still no charge. I will deal with the cock up first. The facts are it did stop charging out of the blue. The dynamo is fine. When I checked the connections to the old reg it looks like I transposed the field/dynamo wires when I plugged it back together. So no charge at the ammeter(red) connection, or somehow 3 volts????. Last night I put in the new reg realised my error and wired it up as it should be. Now I have 14.2 volts at the red wire  . When I connect back into the loom nothing at the ammeter nothing across the battery, so whatever went wrong is still present. The ammeter shows discharge when lights on and all lights work. I tried a quick continuity check along the brown/white ammeter wire from the reg to the ammeter connection and got nothing but if I touched the ammeter body the meter buzzed. Is this wrong or a red herring??.
Please some suggestions on how to go about fault finding on this
thanks Andy

[duTch]

 

....... The ammeter shows discharge when lights on and all lights work. ........

 Engine running or not?

 

.......but if I touched the ammeter body the meter buzzed. ....

 Presuming you mean the test meter buzzed; do you have anther reliable ammeter you can swap in? Like maybe use the multi-meter inline and see what happens? (if you didn't already)

 

[JulianS]

The ammeter body should be plastic the only outside metal parts being the connectors and the bezel. Cant see why meter should buzz?

Try substituting another cable (for the brown/white) between the reg output and ammeter and number 3 connector on light switch.

Does the intensity of the lights increase with engine speed?

[KiwiGF]

If you have 12v electrics the white wire should be disconnected eg not connected to the brown wire.

Is it connected to the brown wire? If so you will not get any charging I reckon.

[BSA500]

Right to answer some replies...
1. Engine not running. Start it and no movement to charge
2.Meter buzzed good idea about subbing in the meter
3.Ammeter body is metal all of them have been in the past. I will look ito testing all the wires but it's either the switch or ammeter giving me issue's ?
4. White wire is NOT connected. Testing at the reg from the red wire gives me 14.2 volts as it should. From there to the bike electrics it disappears.

[JulianS]

The first thing I suggest you establish is whether any current is getting to the ammeter via the brown/white cable.

Presuming that the regulator red cable is connected to the brown/white which goes to ammeter and light switch, then disconnect the brown/white from ammeter and switch and  a test with engine running should show the about same voltage at disconnected end of brown/white end as it does at the red cable.

If not then logically the cable or connection with the red is faulty.