Volvo Penta 3.0l alternator output

[scb1712]

Hi All,

I've got a 2001 Glastron 175SX with a Volvo Penta 3.0 in it. Whenever the boat is running the volts are only around 12.2-12.4, and if i Turin on the n'avait ligots or radio they drop to 11.7 or so. The sticker on the si de of the alternator says "12V Output", so my question is, is the alternator performing correctly or should I be getting it rebuilt so that it's closer to 14.4 V output like a comparable auto alternator?

I should add that the boat seems to operate fine and the battery doesn't frequently go flat or anything, so it's more just a curiosity question. Thanks!

 

[dypcdiver]

Check the voltage at the alternator with an accurate gauge. It should be around 13.6 V. Also check at the batteries again with a good gauge. Check the input and the output of the batteries.

 

[dennis461]

Looks like you are running on battery power, no output from alternator/voltage regulator (or very little).

How many hours have you run with the low voltage?

 

[bruceb58]

Check the voltage on the S and E terminals and make sure both of these are 12V. If they are, you need a new alternator.

 

[scb1712]

The battery has lasted for the past 4 sessions that we've owned the boat. It died last week which prompted my post. As the battery always seemed fine despite the low voltage reading, I always thought that it was only supposed to be around the 12.4 range (also because the sticker also says "12 volt output").

 

[bruceb58]

Like the previous poster said, it needs to be 13.6V or so. When they say 12V, that's just a general term..not exact. Distinguishes it from 6v or 24V systems.. A fully charged battery is 12.6V so obviously needs to be charged at a higher voltage than that.

It's also possible you gauge at your dash measures lower than what the alternator puts out because of voltage drops between the battery and the helm.

 

[scb1712]

As it turns out, the alternator was charging at 13.96V when I measured the output with a multimeter. Now I just have to check to see what the actual voltage at the guage is as I have trouble believing that there is almost 1.5V drop from the motor to the guage.

Thanks everyone

 

[Toypirate]

Check for charging voltage at the starter terminal and fuse block there at the starter, also check the terminal on the alternator... if any of them are loose or burnt this could slow charging current and reduce the reading at the gauge.

A 4 year old battery can cause alternator failure, Have it load tested. look for the burnt alternator post symptom, it can cook the insulator bushing on the alternator's output terminal.

 

[Addis]

Does the alternator always put out 13.6 volts even at an ile?