Alternator grounding out or overcharging

[Strider34c]

Hello, I am having an issue with my alternator not properly charging. I am a bit of a greenhorn with this, but I'll try to provide as much detail as I can.

I have a westerbeke 30b on the boat that runs great, a few months ago the old alternator went out, it was an after market that came with the boat. I bought an Arco replacement. Everything seems to hook up just fine. Power to the terminal, R to R and P to P. There is one terminal left labeled L. I don't have anything attached to that currently (I'll get back to this one though).

When I run the engine my volt meter reads 12.5-13. I have another gauge on my instrument panel that reads at 14, which is more What I would expect. But shouldn't these be reading the same when the engine is running? I made a jump from the L to the battery terminal which pushed my volt meter to 15 when the engine was running, but it was grounding the alternator, stayed hot and ran my batteries down when the engine was not running. (I had this set up for about two days until I noticed)

I have two 100watt solar panels that do a great job of keeping my batteries charged, so good that I can't tell if it is the panels or if there is enough charge from the alternator.

I have two deep cycle batteries, I keep one as my house and the second as my designated starter, although I have been using it a bit lately as it has been cloudy and my house has been draining quickly.

So I guess my questions are:
1. Should my DC voltmeter be reading that same 14volt output when the engine/alternator are running?
2. Does it sound like I have the alternator hooked up correctly? What do I need to change?

Any help troubleshooting this would be very much appreciated, thank you all!

[model 10]

I would disconnect the solar so you don't get confused with it's output. Also I would trust your voltmeter reading at the alternator. 12.5-13v is pretty close to batt voltage so it sounds like the alternator is not working. You probably need to give out more info on your system.

[Strider34c]

This message is for those of you who happen upon this thread later with a similar issue. The alternator was not charging the batteries while the engine was running. Everything was hooked up correctly, but positive from the battery terminal to the solenoid had slipped off the solenoid in rough seas. It was being masked by the output of the solar panels. Hope this helps someone in the future.

[DeepFrz]

What solenoid?

[Strider34c]

On the starter, runs to the battery.