A question about a sick spam can
 

I have posted this in Private flying as well so if it is out of place in this forum please delete.

PA38 low voltage light

The saga started 4 months ago with a new alternator.

Low voltage light began to flicker on and off. Ammeter was still reading normally

Regulator was replaced no change.

On the last annual low voltage light was replaced and new battery was installed (non gel)

Now the bloody thing is on all the time.

At all times the Ammeter shows current, jumps up etc if the nav lights are turned on. No dead bat episodes in the morning or radios dropping out etc.

Anyone else experenced this?

I haven't a clue how a low voltage system is set up.

Is it a wheatstone bridge and we need to tune it for zero difference?.

I might add its on a Public CoA and the engineers that look after it give sterling service. But they are flumouxed as well.

MJ

As the problem started with the alternator, is it not conceivable that this component is at fault? You do not mention its replacement in the trouble shooting procedures carried out thus far. I appreciate the item was 'tagged' as serviceable when fitted, but that sadly is not a 100% guarantee of its true status.

Yes that had occured to me as well.

But as I am FI I tend to tread a very careful line with the engineering types. Telling them how to do there jobs etc.

But as they seem to have run out of ideas I though about using pprune.

Next time its down I will see if they will let me run it up with another FI with the cowling off and take some readings with a voltmeter. But as with my car electrics its more by luck than judgment if I come up with fix.

Thanks for your input

MJ