[C320-list] Alternator to batteries

[Warren Updike]

1. You don't want to pay $100/hr for a marine electrician or engine mechanic
2. You find working on your boat part of the pride/challenge of ownership
3. You have time to devote to your boat maintenance
4. You like to learn
Then, go to Amazon and search " calder boat maintenance" and make the best $35 investment in your boat with Calder's "Boatowners Mechanical and Electrical Manual." If it's electrical, electronic, or mechanical, Nigel covers it in this book with how it works, why it doesn't work, how to test it, and how to fix it. With care, study, and preparation YOU can do most things on your boat.

If engines and motors are strangers to you, find someone you know to help you in diagnosing a problem. 

Every boat can be different even from the same manufacturer, so you have to have some idea what to expect. It's possible that your alternator ground is through the case of the alternator and through its attachments to the engine block. It could also be a separate connection on the alternator with a wire to ground. The positive cable will always be on a connector on the alternator. This positive cable may go to the positive connector on the starter. That will take the alternator output to the selected battery bank. The other connections on the alternator are for control of the alternator. Nigel Calder will explain all this and show you how to test each setup. You must know the dangers as well as the procedures. Improper contacts with battery cables can melt/weld tools... and hurt you too.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, Chesapeake Bay

-----Original Message-----
From: John Meyers [mailto:jcmeyers7 at gmail.com] 
Sent: Saturday, March 25, 2017 8:14 PM
To: C320-List at catalina320.com
Subject: Re: [C320-list] Alternator to batteries

Thank you for that important education.

 I am still not an electrician but now I know more.

John Meyers

On Mar 25, 2017 8:01 PM, "Stephen Cox" <scox at timmin.com> wrote:


> I am no electrician so I don't know if this will work. I
> assume that there are wires from the alternator directly to
> the battery(?) If so can the positive wire (maybe the
> negative wire too) be CAREFULLY disconnected from the battery
> after the engine is running and have a volt meter test the
> output on those disconnected wire?
>

DO NOT DISCONNECT THE WIRES WHILE ENGINE IS RUNNING!!!!

First off you don't need to disconnect the wires to measure the voltage on
them.

Secondly, if you run the alternator without a load it is equivalent to
switching the 0-1-2 switch through the 0 position when running and will most
likely fry the alternator diodes.



Stephen Cox
Tegwen #1141