High voltage from alternator

[grahamdouglass]

When I did my oil change and filter changes this year I noticed I had a high output of voltage, 15.43 Volts at 1000 rpm when I ran the engine for the first time this year. I could hear my batteries boiling.

I have a Powerline 150 amp alternator controlled by a "Powerline Electronic Voltage Regulator Model 10-2". And the power cable goes to a Victron energy Argofett isolator that feeds a house bank and start battery. The batteries are also connected via an ACR. I couldn't find an exact replacement model for the voltage regulator but the alternator repair shop I went to found a generic replacement.

He spent some time and explained a couple of things to me. He said the cause of the voltage spike could be one of two things.

1) The voltage regulator is faulty.

2) The sensing wire from the Alternator to the voltage regulator is bad. Either from a loose connection inside the Alternator or the wire went bad itself.

So the question I want to ask the trawlerites is this. Has any one had a similar problem of high voltage from the alternator and what was the fault?

 

[rgano]

Following

 

[High Wire]

15.3 is way too high. VR is going bad or being fooled into sensing batteries too low.
Small point but batteries are not boiling but off gassing hydrogen gas in large quantities. Can be a very dangerous condition if it builds up in an area then ignites.

 

[C lectric]

It is usually a failing regulator. However the alternator shop guy has a point.

If the sense wire has failed, corroded, or has poor connections from poor crimps, loose terminals then the regulator may be reading a low voltage output from the alternator and thus will jack the volts up.


Often done and better is the sense wire is run directly to the batteries. That allows the regulator to see the voltage at the battery and compensate for any voltage losses in the wiring between the alt. and the batteries including any isolators, diode or mosfet based.

The sense wire should be fused.

 

[grahamdouglass]

Replacement voltage regulator already installed and working.

 

[Mischief Managed]

Just curious, why an isolator and an ACR?