1. I don't understand this but I believe others have reported similar phenomena. To this point I have been just living with it.
2. However, recently I have noticed that the voltmeter at the helm is quivering most of the time when the alternator is bulk charging and the e-meter tells me that the voltage is jumping around between 14.50 and 14.85. The belt is tight and there is no slippage.
So here is my question. I think this a new development. Does anyone know if that much oscillation in voltage is something to be concerned about?
1. The reason, not a phenomena, is that the regulator is seeing the batteries as FULL. Once full it cuts back the AO.
2. My panel voltmeter jumps when the autopilot operates. I attribute this, on my boat, to the fact that when the PO had it installed, the installer chose to tap the AP power off the panel power wire. It could be any number of things on your boat: loads starting always drop the voltage. However, in electrical, any time and almost every time there is intermittent operation of anything, it is due to loose or poor or deteriorating connections.
Good luck.