Rewiring with 1/0 cable.

[Ed Schenck]

This wiring project has turned out to be a lot more work than anticipated. Despite what Maine Sail says a 1/0 cable is tough to work with. All I can think is that he and others with large battery cable have much bigger boats. Or at least a lot better access. The first picture is the starter post where I am trying to connect the new 1/0 cable. The lugs are thick and leave very few threads on the posts. The cable doesn't twist easily so getting several lugs on, four in this case, where you can't even get a hand is no fun. Gave up on this part at end of day.

Did manage to get down into the locker and wire the panel. It is shown without the covers over the fuse and new 12v bus. I forgot to buy the 1/0 cable from the charger fuse to the bus. Also mounted the fuse in the bilge where the two new 6v batteries will live.

Then I was able to use a drum sander on the drill to enlarge the original battery switch hole. The new Blue Sea switch then inserts from the back.

Anybody need fifty feet of #4 cable, lots of pieces, both red and black.

 

[brian3820]

Ed, looking great. That cable does look at little difficult to deal with, but I am sure it will all come together in the end. Great Job.

 

[Maine Sail]

Ed,

Why are there 4 lugs on the stater post? Who's 1/0 cable do you have?

 

[Ed Schenck]

Maine Sail, just one thick lug from GenuineDealz on the 1/0 cable. Then three very thin lugs, one to the Balmar for exciter and two to the panel. Some years ago I ran a second panel #12 instead of trying to replace the original with something heavier.

That starter post is in an impossible place to work. I got the nut off by using two extensions on my socket wrench. Just forward of the starter and unseen is the engine mount. There is no access from the top or back. And no way will there be enough threads for the lock washer. Maybe I can use a fiber locknut.

 

[Stu Jackson]

Ed, MS and I have had this discussion before. I still have the #4 wire from the C post of my 1-2-B switch to the starter. Based on MS's recording of the starting current, i gotta keep sayin' it works for me. I upped the AO to #2, not 2/0!!!, to house bank. Boat still hasn't burned down in spite of always craving somethin' newer!

 

[Ed Schenck]

That makes no sense to me Stu. Why have 1/0 cable from the batteries to the bus to the switch and then #4 to the starter? This boat had #4 everywhere for thirty years and I decide to upgrade. And why didn't I do it ten years ago? Working upside down in that locker and then driving ninety miles home is getting to be too much.

Oh, and my AO wire is a #4. It is the top wire on the bus bar.

 

[Stu Jackson]

Ah, well, we all have different drummers. My alternator is 100A and with my 390 ah house bank I see about half of it on a 50% SOC. Nice work.

 

[Maine Sail]

Maine Sail, just one thick lug from GenuineDealz on the 1/0 cable. Then three very thin lugs, one to the Balmar for exciter and two to the panel. Some years ago I ran a second panel #12 instead of trying to replace the original with something heavier.

That starter post is in an impossible place to work. I got the nut off by using two extensions on my socket wrench. Just forward of the starter and unseen is the engine mount. There is no access from the top or back. And no way will there be enough threads for the lock washer. Maybe I can use a fiber locknut.

What panel? Are you using the starter lug to feed the DC panel? DC panel shoud ideally come directly of the "C" post of the battery switch or a POS dist buss down stream of the "C" post.. The starter post is not intended to be a dist buss..

The Balmar does not need to be there either as if this is your "ON" for the reg it will be on any time your battery switch is on. The "ON" for the regulator should be key switched by the ignition... I am not clear as to what you mean by "excite" what color Balmar wire is this??

 

[Ed Schenck]

All the Cherubinis were wired this way Maine Sail. Common from battery switch to starter post. Alternator to the same starter post. DC #12 wire from that same post to electrical panel. If it weren't so late I could reference a schematic here on SBO. In the picture of the back of the Balmar it is a wire from the top post spliced into the Yanmar cable. The bottom post is where I removed the wire to the starter and installed the #4 that you see there. Goes directly to the bus bar.

 

[Jim Legere]

Quite right Ed, as the original schematic drawing you uploaded to the Boat Info section here on HOW shows - the engine starter was a sort of "+ DC distribution point" as originally wired. This was kind of an 'automotive' design philosophy that was common on boats back then.

When I rewired my boat, I ran a dedicated #6 AWG (or was it #8?...can't remember!) wire from the DC ditribution panel at the nav station to an 80 A fuse block located right beside the battery selector switch. For the 1750 W inverter, I took a #2 AWG feeder from a fuse next to the relocated battery bank under the cabin sole. All my heavy wiring (I used #2 AWG) is fused except the runs from the batteries to the battery switch and from the battery switch to the starter. That was correct according to ABYC recommended practice at the time. I am now planning to put fuses next to the batteries, as you did in your new design.

Interestingly, all the big DC negative wires still go back to the engine block. I had to install a longer bolt after I put in the inverter and the windlass

 

[Ed Schenck]

Maine Sail, about that Balmar. You are right of course, there is no exciter voltage. You asked how many wires. In the picture of the Balmar there are two gray cables with old tape on them. One is the 12v to the starter, the other a ground. They go into a harness. Where the 12v wire comes out of the harness at the starter there are two thin lugs. They were both on the starter post along with the #4 and the two #10s to the panel. I thought that second lug was from the second gray cable. Obviously not or I would have been tying the 12v to case ground on the alternator. So not having a good Yanmar diagram I am in the dark about that lug.

Jim, that is much better solution. It is a pain that the starter, alternator, and electrical panel are on port with the batteries and battery switch on starboard. I never saw a real problem with the orginal setup though. Never had a problem until I decided it would be better to have the alternator tied directly to the 12v bus bar. I had added the second 12v #10(not #12 as previously guessed at) when I still had the 2QM20. I guess I should have just left the original wire and ran one heavier wire. But the wire lugs for the alternator and those two #10s are very thin. Its just that the 1/0 lugs are so thick. And I did size the various ends for the post/bolt sizes with GenuineDealz.

 

[Maine Sail]

All the Cherubinis were wired this way Maine Sail. Common from battery switch to starter post. Alternator to the same starter post. DC #12 wire from that same post to electrical panel. If it weren't so late I could reference a schematic here on SBO. In the picture of the back of the Balmar it is a wire from the top post spliced into the Yanmar cable. The bottom post is where I removed the wire to the starter and installed the #4 that you see there. Goes directly to the bus bar.

I am aware of that but can't believe anyone still has it there.. Voltage transients can cause real problems with the DC panel pulling directly off the starter lug. Not to mention that you are at the very end of the voltage drop in the system at the starter lug...

You lost me on why there is a Balmar wire is on the starter lug again..? If you ran the output to the house then there should not be any need to have a Balmar wire on the starter post...

Balmar Alt -

B+ to battery bank
B- to neg of battery bank or tie onto lug for battery at engine

Regulator -

Black = Ground (to ships DC neg ground buss)
Red = power/voltage sense if your alt goes to the house bank you should sense the house. (Some regs like the MC-614 have an additional red wire to sense)
Brown = Key on ignition (turns the reg on)
Blue = Field wire (energizes the alt and controls field voltage/current)
White = AC tap / stator (runs a tach)

Still, no need to have the regulator tied into the starter post if the alt is feeding the house bank.. I never like feeding sensitive electronics (regulator) directly off the starter lug. Closer to the battery with neg and pos leads insulates them from transients considerably better.

 

[Ed Schenck]

You are doubtless right Maine Sail. But I would bet you that 90% or more of the Cherubini's are still wired that way. And to repeat myself there was never a problem. I have at best five hours a week to work on the boat. Somehow I have to get the common on the starter and 12 volts to the panel.

I reviewed my wiring diagrams and now realize what I was looking at. Out of the harness and in the same small cable were two small wires with lugs at the starter post. One was from the alternator, the one removed. The other is the hot wire to the ignition. It just confused me that the two wires were in exactly the same kind of cable seen at the alternator end.

Wednesday is looking like sun and 42. I'll give it another shot. I just wish the wiring was the only thing on my to-do.

 

[Ed Schenck]

So the first part of my new plan is to quit stressing about an early launch. Hard to do because I have not been on the boat since May 2010.

Next is to rewire the 12v to the panel. I'll run a #8 or #6 red from the back of the battery switch across the engine and fuel tank to the panel. I'll run a #8 or #6 black to somewhere new on the engine block from the panel. Maybe that will free up enough space on the original stud for the new 1/0 ground plus a lock washer. If I can I will pull out the two #10 cables that currently supply 12v to the panel from the starter post.

That will leave just two lugs for the starter post, the new 1/0 cable from Common and the harness wire to the Yanmar panel for starting. Maybe I can get those two wires on the starter post.

Then I guess I should place another order with GenuineDealz: http://shop.genuinedealz.com/Marine Grade Wire/Marine Battery Cable/8 AWG Battery Cable UL/ . At a dollar a foot I guess I better wait until I measure. Should I be using yellow for ground?

 

[Ed Schenck]

Hey Jim, any better recollection of wire gauge for the 12 volts to panel? I figure about 12 feet from battery switch to panel. The calculator shows a 1.6% voltage drop at 20 amps for #6 and 2.6% with #8. Is either a concern? Twenty amps of continuous use would be rare, just looking at a maximum.

And how do you connect a #6 wire to the small bus on our H37C panels? The screw sizes are very small. I guess I can ask GenuineDealz.

 

[Jim Legere]

Ed, I used a #6 AWG. As you can see in the photo, Its big but it is possible to attach it to the main breaker.

 

[Ed Schenck]

I don't recognize that Jim. There is nothing that neat on my boat.

So there must be a way to get a reasonably sized lug on that huge wire. You wrote "main breaker" though. My panel does not have a 12 volt main. Rather it has two bus bars common to all the 12v breakers. . . . I think.

 

[Jim Legere]

So there must be a way to get a reasonably sized lug on that huge wire. You wrote "main breaker" though. My panel does not have a 12 volt main. Rather it has two bus bars common to all the 12v breakers. . . . I think.

I guess that's another difference to enter in the database. My switchboard was/is 3 separate black "Bass" brand panels (which I joned together on a common hinge). The AC circuits are on the left on my boat and the top breaker in the middle row is the 'master breaker' for the rest of the DC circuits. Originally there were 4 or 5 blanks on the lower end of the right hand panel, including, I think, a fuse holder for the extra brown wire to the bilge pump. I added extra circuit breakers. Anyway, I reckon you can source a #6 AWG lug that will fit a busbar screw - I think I used a Blue Seas lug.

BTW, if I were installing a hinge on the switchboard today, I would do it the way Phillipe (Mathurin II) did on his boat (see attached photo) - much easier access!

 

[Maine Sail]

Hey Jim, any better recollection of wire gauge for the 12 volts to panel? I figure about 12 feet from battery switch to panel. The calculator shows a 1.6% voltage drop at 20 amps for #6 and 2.6% with #8. Is either a concern? Twenty amps of continuous use would be rare, just looking at a maximum.

The ABYC standard for "critical circuits" (running lights, nav equipment, and anything else that could be "critical" is for a max or 3% voltage drop. Items like cabin lights can be up to 10% VD.

And how do you connect a #6 wire to the small bus on our H37C panels? The screw sizes are very small. I guess I can ask GenuineDealz.

Find out what size stud you have then order a 6 GA X #10 or what ever stud hole you need.

You would be amazed what you can do with 6GA wire.. Re-built this panel for a customer over the weekend and the only thing that will remain, when done, will be the physical panel board. Note the 6GA wire feeding the three rows of new circuit breakers... This is rather precise work but it can be done. The factory wiring from "C" post to buss bars was 10GA and there was some pretty bad voltage drop.

 

[Ed Schenck]

Great pictures guys, more than worth a thousand words. I was in awe of Jim's panel work when I first saw it, still am. Although it looks like the AC is on the right in the picture. Your photo shows exactly what I am up against Maine Sail. Including the little jumper between the two banks. And I assume I should have a fuse on my 12-foot #6 somewhere close to the battery switch.