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sailinbob1 · 04-03-2017, 16:40

I recently hooked up a new engine instrument cluster. While wiring the volt meter,I noticed that there wasn't a wire running from the alternator to the batteries. I had a friend replace the alternator when I first got the boat,and,not being a mechanic, never thought to look. I've got 2 AGM batteries running to an isolation switch, which are charged by a 100 watt flexible solar panel, that is run through a Sun Saver 6 controller box. The panel is 11 ft long,and 14 inches wide, and keeps the batteries above 13 volts,and I seldom get lower than 12.6 volts. What I'd like to ask is,where should I run the wire from the alternator to the batteries. Presently, I've got it running to a single positive bus, that connects to the electrical distribution panel, to the isolation switch, then runs to the batteries. I'd also like to know what guage wire I need to use going from the alternator to, wherever, I'm supposed to run it. Be looking forward to hearing from ya'll soon. Thanks.

barnakiel · 04-03-2017, 17:05

Quote:

Originally Posted by sailinbob1

there wasn't a wire running from the alternator to the batteries

Get a pro sort this out for you.

It is a high amperage cable. Finger-thick. And your diodes may have been cooked too.

Cheers,
b.

pcmm · 04-03-2017, 17:25

Quote:

Originally Posted by barnakiel

Get a pro sort this out for you.

It is a high amperage cable. Finger-thick. And your diodes may have been cooked too.

Cheers,
b.

Find the wiring diagram for your engine. the alternator might just feed the amps back to the batteries through the starter cable. This is often the case with the default setup.

sailinbob1 · 04-03-2017, 17:26

Not so. I'm not having a problem, just trying to avoid one. My alternator is putting out 14 volts. It just isn't going to the batteries. Or wasn't. The one concern is had was overcharging the batteries. My controller box only allows so much juice to go to the batteries, I mean that's it's purpose. Everything on the boat works. I'm adding a 13 switch AC/ DC electrical distribution panel from Paneltronics soon,since the previous owner took out the original panel, and has everything piggybacked on a 6 switch panel. My original question is, what guage wire do I need to run from the alternator,and where does it go? Presently, I've got it running to a single bus, that is connected to the isolation switch ,and the switch panel,which are connected to the batteries. My thought is, that with the isolation switch in the 'both' position, and the engine running, it would be feeding the batteries. I've definitely got to get a heavier guage wire,which is what I thought. Seemed a little small. My second question is,does the alternator regulate how much juice goes to the batteries, like the controller box for the solar? Or is there some other component? Thanks for your input.

Stu Jackson · 04-03-2017, 17:28

OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowner...d.php?t=137615

This is a newer primer for boat system wiring design with a thorough digram: Building a Good Foundation (October 2016)
http://forums.sailboatowners.com/ind.../#post-1332240

The Short Version of the 1-2-B Switch Stuff: Electrical Systems 101 This is a link to the Electrical Systems 101 Topic, reply #2

What are ACRs, Combiners & Echo Chargers? (by Maine Sail)
http://forums.catalina.sailboatowner...d.php?p=742417

sailinbob1 · 04-03-2017, 17:41

Quote:

Originally Posted by pcmm

Find the wiring diagram for your engine. the alternator might just feed the amps back to the batteries through the starter cable. This is often the case with the default setup.

Ok,that makes sense. I'll call Yanmar, and ask if that's the case. It's a 70s/80s model 2qm20 Yanmar. The Chance 30/30 came with a gas engine, and,as is often the case, there's wire running every wear. I'm pulling her out this summer, and will have a problem look at it. In the mean time, I'm moored in the bay,and fixing what I can,so I can safely operate the boat. It just seemed strange that there was nothing connecting the alternator to the batteries. Since that's the alternator's purpose. I don't use a lot of juice,and only run the engine going out, and coming back. No TV, minor electronics (Hummingbird 365i depth finder),and my lights. Since I wasn't having a problem, I'll remove the wire,until I get more information. Thanks.

sailinbob1 · 04-03-2017, 17:45

Thanks Stu, I'll check those out.

sailinbob1 · 04-03-2017, 18:02

Ok,think I've got it. Thanks Stu. I'll remove the wire, and ask a friend who's a sailor, and a nuclear electrical engineer. Just thought I'd get some feedback from the forum, which I have. Looking at the diagram in the isolation switch link makes sense to me. The alternator feeds the batteries via the starter. Which goes to the batteries. Correct? I'm a carpenter/tooler,not a mechanic, or electrician,but I'm trainable, and since,when there's a problem, it may not be convenient, or even possible, to get a pro. I'd like to know what goes where, and what my alternatives are when things go wrong. Thanks again!

wjsobers · 21-05-2017, 21:59

The wire from the Bat terminal on the alternator should run to the positive battery cable. Most cables have the wire already attached. The same wire on the negative cable is for grounding the circuit.