Alternator output to.....

[Justin_NSA]

1992 Hunter 30T. I'm trying to trace my alternator's output so I can move it to my 'charging buss'. It looks like it runs up to the engine control panel in the cockpit. I can't understand why though or where it goes from there. Before I take too much apart, does anyone have a diagram of how the panel is wired? My manuals don't show it. Thanks!

 

[obxjeff]

Are ypu sure the wire going to the panel isn't the 12v "ignition on" indicator that tells the regulator to enable the alternator?

If it is the alternator output then just add a wire from the alternator to the charging buss, and attach them both (existing and new) to the alternator. Romoving the existing will likely cause some things to stop working.

Be sure each wire is sized for 100% output of the alternator...

 

[Justin_NSA]

It's probably a 10ga wire that goes into the panel. I just may have to open the panel to sort this out. I don't want to break anything. I just assumed the wire would run to the batteries somehow.

 

[Ralph Johnstone]

Romoving the existing will likely cause some things to stop working.

Yes, it will instantly destroy the diodes in the alternator which is a bit of a bugger to say the least. Best not to do this.

I'm trying to trace my alternator's output

I don't think the path of the alternator output has changed much over the years. The alt. feeds back to the starter motor (+) terminal which leads back to the house and starter battery via the 1/2/BOTH switch. It's a convenient way of returning a large(r) current back to the batteries.

I'm trying to trace my alternator's output so I can move it to my 'charging buss'.

What's a charging buss ? You've got one I trust, I've just never heard of one.

 

[heritage]

Is there a larger wire going from the alternator to the starter? If so, then the alternator current is sent to the battery through the battery to starter cable.

 

[Ralph Johnstone]

current is sent to the battery through the battery

Can you please clarify ?

 

[Stu Jackson]

It's a convenient way of returning a large(r) current back to the batteries.

Ralph's right. Here's why:
OEM 1-2-B Switch Wiring History Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

1-2-B Considerations (New 2020 - Rod finally got around to diagramming what I had done in the above link in 2009 )
1/2/BOTH Switch Considerations

 

[Justin_NSA]

I don't think the path of the alternator output has changed much over the years. The alt. feeds back to the starter motor (+) terminal which leads back to the house and starter battery via the 1/2/BOTH switch. It's a convenient way of returning a large(r) current back to the batteries.

What's a charging buss ? You've got one I trust, I've just never heard of one.

My alternator wiring is untouched and it doesn't go to the starter motor unless it takes the scenic route thru the cockpit control panel. This is why I was hoping to locate a diagram for the Hunter.

I was an MOS 6336 - Aircraft Electrical Systems Technician in the service, so I have a good grasp on the subject. I'm trying to add the alternator to the "buss" I made based on MainSail's fabulous article on wiring marine chargers. I don't have an inverter as shown in his picture.

 

[Stu Jackson]

My alternator wiring is untouched and it doesn't go to the starter motor unless it takes the scenic route thru the cockpit control panel.

Do you have an ammeter in your cockpit panel?

 

[Justin_NSA]

Do you have an ammeter in your cockpit panel?

That would make sense, but I don't

 

[Stu Jackson]

That would make sense, but I don't

OK, so let's do some engineering.
BlueSea wire sizing chart says 10 AWG good for 10A 30 feet, 30A 10 feet.
A 30 foot boat of your vintage most likely has a stock 55A alternator. Since that's cold rated and well know most don't put out anywhere their near rated output unless batteries are really empty or with an external regulator, it appears that say with a 55A alternator putting out 30A running a #10 wire as the alternator output is 1) not a good choice for load carrying and 2) not a good choice to run to the cockpit panel at all because as Ralph said most builders ran the AO to the C post of the 1-2-B switch AND (as I posted in my links) they did this VIA the same wire used to power the starter. In almost all cases that I am aware of (and having owned my boat for 25 years and very active in boat electrical stuff) a #10 wire would be INADEQUATE to power a starter. Most Catalina 30s, for example, of 1970-1990 vintage had #4 AWG to the starter. #10 would be adequate for the short distance between the starter and the alternator which Maine Sail discusses in his link.
Some builders did run #10 wiring to their cockpit panels for ammeters. Absent an ammeter, either you had one and it was removed OR that wire powers something else. Most likely some solenoid or relay; or abandoned.
At this point, asking what other people have or what might have been OEM is, I believe a waste of your time.
Rather I suggest you spend your time doing a real wiring diagram of this portion of your boat based on what you actually have in front of you. You're there, we're not.
Good luck, keep us posted.

Here's another MS link: Universal Diesel Engine - Wiring Harness Upgrade - Marine How To

 

[Justin_NSA]

OK, so let's do some engineering.
BlueSea wire sizing chart says 10 AWG good for 10A 30 feet, 30A 10 feet.
A 30 foot boat of your vintage most likely has a stock 55A alternator. Since that's cold rated and well know most don't put out anywhere their near rated output unless batteries are really empty or with an external regulator, it appears that say with a 55A alternator putting out 30A running a #10 wire as the alternator output is 1) not a good choice for load carrying and 2) not a good choice to run to the cockpit panel at all because as Ralph said most builders ran the AO to the C post of the 1-2-B switch AND (as I posted in my links) they did this VIA the same wire used to power the starter. In almost all cases that I am aware of (and having owned my boat for 25 years and very active in boat electrical stuff) a #10 wire would be INADEQUATE to power a starter. Most Catalina 30s, for example, of 1970-1990 vintage had #4 AWG to the starter. #10 would be adequate for the short distance between the starter and the alternator which Maine Sail discusses in his link.
Some builders did run #10 wiring to their cockpit panels for ammeters. Absent an ammeter, either you had one and it was removed OR that wire powers something else. Most likely some solenoid or relay; or abandoned.
At this point, asking what other people have or what might have been OEM is, I believe a waste of your time.
Rather I suggest you spend your time doing a real wiring diagram of this portion of your boat based on what you actually have in front of you. You're there, we're not.
Good luck, keep us posted.

Here's another MS link: Universal Diesel Engine - Wiring Harness Upgrade - Marine How To

Make sense Stu. Just to be clear though, the wire from my starter to the AB switch is much larger.

 

[Stu Jackson]

the wire from my starter to the AB switch is much larger.

We should hope so!
But that wasn't your question, was it?
Is there a connection between your AO and the starter like in Maine Sail's links? (Forgive me if you mentioned this or not earlier.)

 

[Justin_NSA]

We should hope so!
But that wasn't your question, was it?
Is there a connection between your AO and the starter like in Maine Sail's links? (Forgive me if you mentioned this or not earlier.)

I will have to meter between them. I see no direct connection. They are only about 1 foot apart. I'll table this until I learn more

 

[Ralph Johnstone]

This is why I was hoping to locate a diagram for the Hunter.

Don't waste your time looking for a copy of the charging system of a Hunter. This is mine from my 1999 H-310 manual that came with the boat as new. I've kept the copy resolution as high as possible but the wiring at the alternator and starter is just chicken scratches.

 

[Justin_NSA]

Don't waste your time looking for a copy of the charging system of a Hunter. This is mine from my 1999 H-310 manual that came with the boat as new. I've kept the copy resolution as high as possible but the wiring at the alternator and starter is just chicken scratches.

Thanks Ralph. That was the diagram I don't have for the 30T. It does show how you'd expect the alternator output to travel to the AB switch. I really need to trace mine because I don't see any wires behind the switch that might be it - just to what I think is behind the cockpit control. Thanks again.

 

[Ralph Johnstone]

Justin, have you ever played with one of these :

Amazon.ca

I bought one of these over 10+ years ago looking for a wire in the boat. I paid next to nothing for what I thought was a real piece of crap. I was within inches of heaving it into the ash can until I started to get the hang of using it. Nothing in the instructions about the finer points of using the tracker. It was an art, more than anything else but I got to where I could trace a wire, stashed in bundles, from one end of the boat to the other in one fell swoop, usually more often than not. It did the job for me.

Fast forward 10+ years and I'm sure they're vastly improved from what they were back then. Probably don't even have to be on your boat to trace the wire .

 

[Justin_NSA]

Interesting. I have never seen these before. I thought I had all the cool gadgets.

 

[Jkutyna]

Justin, have you ever played with one of these :

View attachment 220115

Amazon.ca

I bought one of these over 10+ years ago looking for a wire in the boat. I paid next to nothing for what I thought was a real piece of crap. I was within inches of heaving it into the ash can until I started to get the hang of using it. Nothing in the instructions about the finer points of using the tracker. It was an art, more than anything else but I got to where I could trace a wire, stashed in bundles, from one end of the boat to the other in one fell swoop, usually more often than not. It did the job for me.

Fast forward 10+ years and I'm sure they're vastly improved from what they were back then. Probably don't even have to be on your boat to trace the wire .

I didn't want to be 'that guy' but as a former naval nuclear electrician, this was my first bit of advice to you. After 30+ years, nobody has a boat that is OEM anymore, so asking what others have isn't going to be too useful. You can get a toner/tracer on Amazon for as little as 20$ or less now a days and it will save you soooooo much time.

 

[jssailem]

Justin. There are many ways to structure your electrical system. I dished the 1/2/Both switch in favor of a three switch system that isolates the House from a starter battery. For charging I installed an ACR switch that allows the start battery to be charged once the house bank is charged. In a failure the third switch can couple the house and start batteries together. All charge sources go to the positive block, connected to the House positive post. The House negative post goes to a negative block which attaches to engine block. It’s a pretty simple structure.