High Voltage Alarm

[Mark Gillespie]

We have a model year 2014 Back Cove 37 (BC37) vessel. The BC37 has a Cummins QSC 600 HP engine with a 12 VDC system. When we brought the BC37 up to cruising speed, we received High Voltage alarms on our Blue Seas Voltage Meter display. We saw 16+ volts at cruising speed on the Blue Seas and the Smartcraft display; with the voltage jumping between 14.3v and 16v. When I brought the boat down to idle speed, the voltage settled down to 14.1v to 14.3v.

The alternator for the QSC is the original alternator that came with the engine. There is no external VR.

All electrical equipment on the boat is OEM.

I am looking for suggestions / recommendations on how to diagnose this issue.

Thank you in advance for any assistance.

Topic

[Corey Schmidt]

I would start by disconnecting the alternator BAT+ output lead and have someone measure the actual output of the alternator with a voltmeter while the engine is running and you’re under way… that will at least corroborate the displays, alarms, etc.

Then, you can at least focus on the alternator itself before spinning your wheels with any other external equipment if the alternator is in fact malfunctioning.

Start there…

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