High Voltage Alarm

[Fred Slane]

There is a persistent high voltage alarm on my port engine. Voltage readings fluctuate, with readings above 15.5 v.
The alternator has been replaced to address this problem. It persists.
The batteries have been replaced to address this problem. It persists.

What is my next step in solving this problem?

Thanks,
Fred
Archimedes II
2004 390 Motor Yacht

 

[Arminius]

A high resistance connection might do it. The load of the battery helps to regulate the output of the alternator. Jump around each connection to see if voltage goes down. EG: Your battery switch hooks the alternator to a battery but the switch could be defective. Jump across it with high amp cable, even an ordinary battery jumper. Hope you are using a test instrument as otherwise the gauge/alarm could be suspect.

 

[Korkie]

Do you have an internal or external regulator. Most have internal, although POs may have converted over to an external to get more amps.

 

[hughespat57]

I am not going to assume anything so...

1. The alarm is coming from the Cummins engine control system? or some other (Vessel View)?
2. You checked the voltage before replacing the alternator with a separate voltmeter/multimeter and that showed high voltage of 15.5v?
3. You still had a high voltage on a separate meter after the alternator so you replaced the batteries?
4. The port and starboard engines have completely independent batteries/alternators? No shared charging for House battery such as Isolators, ACR, etc.?
5. The shore power AC battery chargers are off at the time of testing (no AC shore power & no AC generator power)?

 

[Arminius]

If functionality is good and battery is not boiling, why worry? Routinely open, wire brush, and lube all suspect junctions.

 

[Fred Slane]

I'll continue to listen to ideas. What is posted is very helpful. I'll be back on the boat in two weeks.

Fred