1960 C1 dynamo

[Patrick]

Hi all - took my car out at night and noticed a massive discharge on the brand new battery with the lights on - could this be the dynamo brushes giving out?

 

[Oneball]

Could be. But could be a bunch of other things too such as the regulator.

Did the discharge (I’m assuming you’ve got an ammeter) change with revs?

 

[Patrick]

Yes it did recover with high revs (in excess of 2000) but only to 0 on the ammeter.

A few days prior, I took it to the Goodwood revival. It started to overheat in the traffic queue (unusual as it has a 160 degree thermostat) so I shut it down and there was no juice in the battery to start it again (hence the new battery ).

 

[Patrick]

Update on this - the dynamo and regulator have been checked and tested with no issues. Still no charge going through to the battery. Can’t see any circuit breakers under the drivers dash that are relevant (just lights etc). Checked the battery earth and that’s clean and tight.
Any suggestions please?

 

[teamzr1]

Using a D/C volt meter
With car off what is the reported voltage read ?
With the engine running at idle, what does the voltage report ?
Reving the engine up, what does it then report ?

At idle, measure voltage at the generator output post, what it reads ?
And then the other end of that wire connected to fuse block read ?

If no output seen and that wire is good than maybe a fuse link has blown

Should see voltage at battery posts at idle around 14 volts
Check the belt is not loose and pulley of generator not spinning well

 

[Patrick]

It was the dynamo mounting bracket bottom bolt which had corroded and prevented the dynamo from earthing. Also the bracket itself was powder coated which didn’t help matters. It’s now charging like a beast - happy days!