Why was my volt meter fluctuating on one engine?

[D3B]

On the way back yesterday I noticed the starboard engine dial twitching, so dialled up the EVC.

It varied from 13.4 to 13.9 volts.

The port engine was showing 14.0 or 14.1.

Any sparkies with any ideas?

 

[omega2]

electronics drawing power from one battery?? have you got ammeters as well, if so you may find one alternator pushing more amps than the other. The twitching could be the auto pilot switching.

 

[halcyon]

Starboard engine does supply domestic power so check ammeter on cabin panel, does that match the voltmeter movement ?
How fast does the voltage vary ?
Could be worn or sticking brushes, bad connection, could even be a loose alternator.

Brian

 

[Labhaoise]

could be the altentors' regulator wearing out.. i thought it controls the actual voltage output of altenator.. i have seen this with commercial vehicle 24 volt systems

 

[tinkicker0]

depending on how fast it twitches, could be a bad diode not rectifying one phase.

 

[material_girl]

Can only be due to 2 things, load or charger(alternator). As already suggested check amps and if it matches voltage swing try to isolate load and see if it goes away. If not then look the other way, ie alternator.

Regards

Neil