Alternator charge output only 11 5 volts

[sv.divine.grace]

While motoring the engine voltage output is only about 11.5 volts. I suspect alternator failing. Any advice would be appreciated. Thanks.

Alan
Divine Grace #307

[wolfe10]

Yup, something is WRONG.

11.5 VDC is a completely discharged battery-- and if left that way for very long will kill the battery!

Check connections first.

Is this the OE alternator, or have any modifications been done to the alternator, regulator or wiring. I ask because many of us have materially (read that $$$) upgraded the OE charging system. Troubleshooting depends on what you have.

So, post alternator info/any other changes to charging system.

Also, where are you taking the readings: Binnacle gauge? digital volt meter at alternator? digital voltmeter at battery?

[sv.divine.grace]

Thanks Brett. Using my DMM I measured 12.5V at the engine battery before starting the engine and about 12.2V with the engine running at slow idle. No change at higher rpms either. Alternator appears to be consuming voltage. Bad alternator/diode? I am currently at anchor.
Can I run the engine in this condition til I can get it fixed?

I also have a current drain of 0.7amps between the +ve post and +ve cable with engine battery switch shut off.

My contact info is sv.divine.grace@gmail.com
403-804-3270.

[wolfe10]

Yes, you can run the engine until the battery is too discharged to run the electric fuel pump (though if fuel tank is full, may be adequate fuel flow by gravity alone-- no first hand info on this).

You need to start turning off breakers/pulling fuses until you find the parasitic draw.

I would sure head to some place with shore power before you discharge the batteries to a point that they will not recover.

Where are you located. Perhaps someone here can assist.

[sv.divine.grace]

Good info/advise. Thanks. Fortunately I have solar panels to help charge.

Do you think the alternator is bad then?

Since the starter motor works ok, the ground for the alternator should be ok too? Where does the ground wire attach?

I am at anchor off the SW end of Key Biscayne in Florida.

Alan

[wolfe10]

Yes, if wire connections are clean and tight, depending on whether the alternator has an internal or external regulator, it is either a bad alternator OR if external regulator, could be bad regulator.

What alternator or alternator/regulator do you have?

Remember, if batteries stay discharged for very long, it materially shortens their life.

BTW, we were anchored there in January. Boat in the Abacos right now.