17 volt spikes seen on volt meter and GPS unit

[Don Sr]

has anyone seen there volt meter jump to 17 volts while under power/crusing for 30 to 60 seconds then return to 13.5 volts. I'm wondering if this a bad regulator or a bad alternator. Is the alternator and regulator one unit or is this two pieces of equipment? I don't have a generator on board. Thanks

 

[sr330daguy]

Had it happen with an older boat,batteries were very low electrolite.Check you terminals too.

 

[fc3]

Battery, regulator, or connections, especially the sense (red wire) connection to the alternator.