voltage gauge says 10 volts when running

[whosurpopi]

2003 df140 and I noticed the volt gauge saying around 10 volts. I checked the battery with a meter and running its at 11.95 volts, but when I turn the boat off it goes up to 12.06. I know neither is good, but the fact that it goes up when the boat is off tells me it not being charged. I am not getting any beeps or alarms, and the boat runs great. Could it just be a bad ground somewhere Or is it something worse?

[Moonlighter]

What have you checked so far? Done the basics like cleaning battery terminals?

Check main leads. Some years ago a friend was having battery problems on his boat, when I checked the leads they were hard and when flexed, heard/felt some "crunchy" sounds. Turns out they were almost totally corroded internally - a tiny cut in the cable insulation had allowed moisture in and over time the corrosion had got in there. New set of leads, problem solved.

[whosurpopi]

I have cleaned them

I removed them about 2 months ago and sanded them down to nice and shinny. I will check again in the morning and also check the rectifier ground.

[redlowrey]

Do some voltage drop tests starting at the voltage regulator, there are five heavy gauge wires going to your regulator four white and one black, connect the negative on your volt meter to the black ground, make sure it is clean and connect the positive to the white wire going back to the thirty and sixty amp fuses. start the engine and start checking, if you have battery voltage on your meter, you know at least the ground circuit is good. move the positive of the meter to the fuses then to the starter solenoid where the main battery cable is then to the positive on the battery, if the voltage don't change from any of those circuits you may have a faulty alternator or regulator. You may be lucky enough to only have a corrosion problem in the wiring between the regulator and bat pos at the starter. A little tip when your testing circuits with a digital voltmeter, because the meter has very high internal resistance the actual current draw is in the micro amp range, so the meter could show 12 volts on a circuit but if you connected up a test light the circuit would be pulled to ground, zero volts, always have a test light handy.

[whosurpopi]

Thank you for the detailed instructions. I will post results.

[whosurpopi]

Fixed.

It was just a little corrosion on the ground wire. I am now at 14.5 volts. Thank you.