Charge light stays on

Just a thought;

With that type of battery and you fully discharged it is it possible you damaged the battery. Do you have a spare battery to give it a test? 

I asked about the Maintainer/Charger because I was wonder why the battery was Not running down. ???

The Voltage would be expected to drop, and keep dropping,  if the alternator were dead.

Once it drops to 13.5 there is no way for it to get back up to 13.8 unless it was charged.

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Yes! Engine Block = Crankcase.

I suppose technically, a Block is a Crankcase with Integral cylinders as is common in automobiles.

But the terms are often used interchangeably.

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There would be no practical way to measure the AMPerage Output of the Alternator windings.

You could Unplug the Regulator connector and temporarily attach a VOLTmeter to the Yellow(G) Stator leads.

The voltage should be ~18vAC (Alternating Current) or much greater depending on the RPMs.

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Interesting Factoid.

The Yellow Alternator leads are designated "G" on the connector because in the German Language,  Yellow = Gelb;  hence "G"

Hi Roger,

I did test with a spare battery, it was clearly not charging.  Damaged battery was my first thought too, and easiest to fix.  As it turns out I was able to source a regulator much cheaper than a new battery though, so fingers crossed that fixes the problem.

Steve

Folks,

I thought I'd wrap up this post by sharing what I have done to fix the problem.  Following advice from here and elsewhere I did the following:

1) looked to see what the voltge was with engine running - it was lower than battery voltage engine off, so the engine was drawing current, not supplying it to recharge the battery.  Voltages observed are in earlier posts.

1) checked that the Battery was fully charged and that changing out the battery made no difference, which it didn't  (eliminating the battery as the problem).

2) checked for continuity of the C Rand B leads, that they were seeing battery voltage, and that the  regulator was properly earthed to the engine.  All good.

3) checked for continuity of the stator - zero resistance across the 2 yellow stator leads.

4) removed the regulator and checked it and the connector.  I found one of the G (stator) connector tabs on the regulator had evidence of arcing where the female stator crimp connector (yellow G lead) contacted it.  The female connector inside the connector block was melted into the block.  I'm told the arcing is the result of a slightly loose connection, and would make the regulator fail.

5) replaced the regulator, connectors where they were damaged and connector block and reassembled - problem fixed.  The plane is back in the air.

I knew that there was a problem with oveheating ducati regulators, but talking to others it seems regulator failure is not uncommon whether they overheat or not while alternator failure is extremely rare.  I've also become aware of the same type of aeroplane having a cockpit fire as a result of "regulator failure".  Sounds to me like they had the same issue but perhaps the arcing led to a fire.  I was lucky mine didn't.  There was no indication during assembly that there was a loose connection.

Thanks for the advice, stay safe,

Steve

Thanks for the update!

I just had a regulator fail on a 30yo car of mine.  I took the alternator to an old-fashioned small-motor repair shop, which replaced the regulator, and now all is well.  The owner (in business 43 years) told me that he used to get a lot of that kind of work... in the days before cheap, non-repairable alternators from China became ubiquitous.  I think we should be happy to have our (swappable) Ducati regulators.