Intermittent Battery Light

[devilmaycare]

Originally Posted by matrix1975

No, unfortunately the copper plating is very very thin. So I don't imagine it does take much to start stripping it away.

What a cheapskate construction. I wonder if this is typical of modern alternators? At least with the old dynamos, the commutators were far more substantial. I suppose they had to be to handle the larger output current. It used to be possible to clean up commutators with sand paper, but trying that on slip-rings would probably remove most of the plating.

[UK CHRYSLER 300C]

Well having said that^^^ I have a few older cars that have dynamo's 1 a 1965 moggie convertable and 2 Beetles and the "Notch" with original dynamos and they work ok... but so do all of my other petrol cars... lol.. damns diesel modern camper... lol

[Pappajohn]

Originally Posted by matrix1975

No, unfortunately the copper plating is very very thin. So I don't imagine it does take much to start stripping it away.

damp brush dust must be an excellent abrasive.

that was the problem with mine...full of damp dust and crap and it had stripped nearly half the copper slips ring away

[devilmaycare]

Originally Posted by Pappajohn

damp brush dust must be an excellent abrasive.

that was the problem with mine...full of damp dust and crap and it had stripped nearly half the copper slips ring away

Something wrong with the theory here? Carbon is softer than copper, so that brushes can be sacrificed and easily (?) replaced whilst the copper remains intact. You don't mention any lube oil or diesel contamination - is that correct? If so, the culprit must be abrasive dust, but where is this coming from?

[Pappajohn]

Originally Posted by devilmaycare

Something wrong with the theory here? Carbon is softer than copper, so that brushes can be sacrificed and easily (?) replaced whilst the copper remains intact. You don't mention any lube oil or diesel contamination - is that correct? If so, the culprit must be abrasive dust, but where is this coming from?

Agreed, but i reckon the dust could only be carbon.
no oil or fuel cantamination that i could tell by smelling the 'paste', perhaps whatever the damp was could have been abrasive itself.
the brush's were in a bad way with large chunks missing around the edges.
whatever it was it sure ripped into the slip rings.

[devilmaycare]

Perhaps there's something in the brushes, other than carbon, eg some binding substance? If so, it would appear that the brush/slip-ring combination just isn't up to the job. Do you know the alternator manufacturer?

[matrix1975]

Both of my alternators are made by Valeo.

The first failed due to oil/fuel ingress. I've not dismantled this second one yet.

[Simon@thecustom300cshop]

If it were taken to a Lucas store (if they still have them), I wonder if they could come up with a decent alternative to the Valeo one.

[devilmaycare]

Eurocarparts offer Lucas, Bosch, RTX(?), and an unamed make for the CRD. Lucas is the most expensive. No mention of Valeo. My 16 yr old Audi A4 has its original Bosch (Made in Great Britain) alternator, although the Haynes manual states that both Bosch and Valeo alternators were supplied. To be fair, alternator designs, particularly the slip-ring constructions, seem to be similar, so maybe premature failures really are down to contamination exacerbated by the silly location.

[Olly57]

Just saw the thread and thought how similar this problem was to mine (November 2012) - I have had to have the alternator replaced and I see that you mention that the first was replaced due to fuel/oil contamination. I had exactly this along with the split diesel fuel (elbow supply) pipes. Once replaced it was clearer to see that the dash lights no longer (slightly) flickered and that the battery light issue was completely resolved. When I think back, I could have recognised the problem, if I knew what I was looking for and why a lot sooner and "maybe" saved the alternator from complete destruction.

It sounds like you have it covered but from my very little experience maybe the money is still on liquid contamination of some kind that has made the brushes disintegrate causing battery and alternator issues.

Would be interested in the solution in case I need to look out for this as well - still think I am the "Lucky Eddie" of the 300c world.