37c electric panel ground

[sail_4_me]

I'm rebuilding my electric panel, and I found a clipped off wire. I traced it to a keel bolt just behind the mast. Because the wire is 12 awg, and its clipped off, and because the nut on the keelbolt looks like an add-on, I've taken the wire out. Its not in the DC electrical diagram for the 37c...

I'm not sure I want to ground my new Blue Seas 100amp panel ,as all NEG grounds to the engine. I'm curious if anyone else grounds their panel in this way?

(really nasty pre-purchase) Picture of bolt attached. You can see the add-on (rusty) nut and steel plate overtop of what is a stainless steel keelbolt on the right.

I also don't have the 8ga wire noted on the 37c diagram for the mast ground, but the mast base is held down by 2 huge keelbolts, so is it needed? Seems to me the mast can't be grounded any better...

Much gratitude goes out to those on this site who posted the 37c PDF manual. Its Priceless.

I'm still pulling the old electrical tape off wires, untwisting marretts, and muttering "Why, why, why?..."

 

[Jim Legere]

Resources for boat wiring

I know EXACTLY what you are up against, having had to tidy up the wiring on my 37C some 8 years ago. Behind the electrical panels looked worse than the dashboard wiring of 1949 Chev. I don't think any N. American production boatbuilders of the time paid much attention to wiring - as long as it worked.

You mentioned that you have a Blue Seas panel. They have some excellent resource material on their website, explaining not only best practices but also the ABYC and USCG regulations as well as the thinking behind them. Their website has changed since I used it to help rewire my boat, but you can find what you need there: http://bluesea.com/resources

There is also a lot on this site, as you mentioned. Anyway the ground wire to the keel bolt is definitely not original.

 

[sail_4_me]

Hi Jim, I've been working on this project all winter. Blue Seas, Wema and Xantrex all have online docs. Here's what I eventually went with:
-Blue Seas 8408 panel
-Blue Seas 5511e mains switch
-Wema tank monitor and 4 sensors ( 2xwater, fuel, head )
-Xantrex LinkLite battery monitor
-Xantrex Freedom 1800 charger/invertor
-Xantrex echo charger
( And to complete the set, I'll switch to a bigger alternator )

I've got 3 290 series batteries in the bilge and a 4th for the engine in the lazarrete. The alternator (and charger ) connect to the house bank, which charges back to the engine battery through the echo-charger.

This all started because my autopilot would restart everytime I started the engine, causing it (and the boat if engaged) to do a 360. Now only the engine is on the engine battery.

I've attached a pic of my progress so far 8^).

 

[Ed Schenck]

Looks and sounds really good. A lot like mine except that I still have the original panel. And no tank gauges. I did add another #10 to the panel to handle the HAM radio. And I still forget and start the engine on the house bank and wonder why the instruments went off or reset.

Three batteries in the bilge? Must be a fin keel. First time I looked in the bilge of a non-shoal draft H37C I could not believe the difference in depth. I have one of four AGM house batteries in the bilge for 400ah. They would all be there if I had the deep draft, great place for them.

 

[sail_4_me]

Bilge batteries and Panel progress

Hi Ed, here's a picture of my bilge with 2 batteries ( pre-upgrade, so these are 270's ). You can see the plywood shelves made by the PO. On the right was a third battery, but with my electric rebuild I've moved it to the left. I need that spot on the right for a DC multimeter shunt, and a DC neg busbar to connect all negatives ( so that the DC meter reads all power consumed, it all has to come to 1 place ). Underneath the batteries is 18" or so to the bottom. I've got a Rule 2000 bulge pump under there on a float switch.

Here is the new panel in place, minus the radio and VHF. This represents a whole winters work 8^). I finally splash this weekend, with just the engine battery working. I'll test all the connections etc. in my slip.

 

[Ed Schenck]

Yep, that's amazing how much bilge room you have. Love the option of having big batteries there. Not possible on the shoal draft. It looks like your water tank manifold is one frame farther forward. Mine is about even with the galley sink. And a great panel, very nice work.

 

[sail_4_me]

Here is a tough electrical problem for the forum ( tough for me at least ).

I've separated my batteries into 2 banks. One battery is for the engine only. 3 more are for the house. The engine battery pos+ is connected to a switch, which connects to the starter. The engine block connects back to the neg-.

The House bank pos+ is connected to a switch, then to the DC panel, where DC load is destributed. The panel neg-, and all other neg- return lines go to a neg- busbar, which is connected to a shunt (for a DC multimeter). The shunt is the only neg- connected to the house bank, except the parallel wires.

The alternator charges the house bank, and an echo charger charges back to the engine battery.

So, to the question. Do I need to connect a neg- line from the house bank to the engine, and ground the house bank? If I do this, should I connect the neg- line before or after the DC shunt?. Note that the shunt measures all power going through the house bank, so I'm worried that this grounding connection may cause incorrect output on the DC meter when I start the engine. I'm also worried that differences in charges between the 2 banks may bleed back through this connection (or is that only on the pos+ side).

Should I make the neg connection, but through an isolator? Should I ground the house bank to the grounding-strap on the keel ( which started this whole thread in the first place, doh! ).

One other note, my single big red switch turns both banks on/off at the same time, and it supports a parallel option. I think for this reason I need the house grounded to the engine, as a common ground...

Comments appreciated.

 

[Jim Legere]

Grounds

You should have a common ground for all the DC systems on your boat and it is normally the engine block. If you run a ground wire between the house bank negative and the engine block from a connection that is between the house bank neg terminal and the shunt, it will not affect the monitoring instrumentation of your house bank. Remember that the circuit flow for the house is battery positive to loads through shunt and back to battery negative, so as long as your connection to the engine block is between the house battery negative and the shunt, the shunt doesn't care.

If you ever plan on using the Big Red Switch to parallel the house bank to the starter bank (i.e. to start the engine when batteries are low) then the wire from the house bank to the engine block MUST be large enough to handle the starter current (AWG 0?).

You do not need to worry about the two banks "bleeding" to each other as long as the positive sides are kept separate. Do not use a battery isolater on the negative line.

Grounding to the keel is a vestigial notion of "bonding", which is a wholly different concept than "grounding". Bonding is supposed to prevent electrolytic corrosion (although it may promote it) and is also part of discussions on lightening protection and HF radio installation. Bonding is still a contentious subject and should be the topic for a whole other thread.

Incidently, your AC system green wire should be tied in to the engine block ground too and, if you have an inverter, it should have a ground wire from its chassis to the engine block that is large enough to handle the full rated DC load of the inverter and you must have a fuse (and maybe a disconnect switch) on the inverter DC feed.

Disclaimer - I believe all this is the intent of ABYC E-11 from my reading of it, but you should investigate the relevent documents yourself.

 

[sail_4_me]

Thanks for your prompt reply Jim.

I think I was mostly concerned about bleed back through neg- connection if I put that house-to-engine neg- in. I've read a lot about boat wiring but never seen this discussed anywhere.

The Big Red Switch ( Blue seas 5511e ) combiner needs that cross connection to enable the combiner, so thats a given. I also agree the connection should be on the battery side of the shunt. Wire size will be 2/0 or 1/0, along with the parallel wires between the house batteries (+ and - ). This wire size is chosen because the Xantrex 1800 invertor can pull up to 3600 watts momentary. Thats 300 amps ( !! ) pulled from the batteries for inversion. For safety reasons, I have placed a 200 amp fuse in-line to maximize the peak to 2400 Watts/200 amps, as I expect to never plug anything large enough to cause a surge like that. ( laptop, 24" TV, small vacuum, maybe a small Microwave, but no more than 1200 watts max ). The 2/0 wire is oversized for that purpose. ( the invertor also has its own ground directly to the engine, as you noted ). I haven't blown a fuse yet, but I have spares, and could up the size to 300.

I will leave the keel for bonding, but it is also called 'grounding' in terms of the panel I installed, which has a grounding bar for each column of switches. For now I'm not using it. As you said its a whole other subject that can wait until I have the first mess sorted out.

Good point about the grounding for the AC ground. My old panel did not do this. Its a Bass Systems panel and came with the 37c - owners take note.
My AC side has 'circuit interrupts' in the first outlets that tested ok without the ground. I'll probably run this ground wire direct to the engine.

For the grounding bus and shunt, I'm placing them under the floor grate at the bottom of the stairs. My 37c had a battery there. You could see the negative post thru the grill, as you come down the stairs:naughty: and this is dangerous, so its being moved. I'm mounting the shunt and neg- busbar on the cross-brace far enough back that you can't see it, and I'm covering it with a blue seas plastic panel cover that will protect all the wires etc from any water that gets down there.

When done, the only change I should need to make to go saltwater, is to change the batteries from lead-acid to gell. Can't have lead-acid batteries in a saltwater bilge 8^).

Colin

 

[Ed Schenck]

Good explanation Jim. But even with my many years of electrical and electronics experience I still have trouble visualizing. So if I am on my boat I just get out the booklet for the Freddom 20 and review the schematic. The Link 20 manual has a decent diagram: Link 20 diagram . I think you can make this diagram work wherever you happen to physically locate the shunt.

 

[Jim Legere]

Salt water and lead-acid batteries

It interests me that you feel obliged to change from lead acid to gel cell to go "saltwater". Here in Nova Scotia you will find lead acid batteries on everything from fishing boats to yachts. One of the leading manufacturers of lead acid batteries (Rolls & Surette) is located here.

I have a very similar setup to your H37C, with 3 batteries under the cabin sole. With the tops of these batteries about 3 or 4 inches below the sole, I figure it would probably take a 100 gallons or more of water before the batteries were submerged. My high water alarm would be keeping me busy with the pumps long before that happened.

Now if you want to put in gel cells or AGM batteries for their low maintenance or deep discharge advantages, I can understand...but because you are sailing in saltwater? I don't think you need to worry...unless you are in a submarine and can't get fresh air - remember the movie Das Bot?

Anyway, great job on your electrical overhaul! If the saltwater you plan to sail in laps the Nova Scotia shores, stop by for a visit.

Jim

 

[sail_4_me]

Salt water and lead-acid batteries

Was a comment I'd read several times, but I've never heard of any boaters gassing themselves lately. I've also read that i should have a few boxes of baking soda around in case of a leak. (stored in the head to remove odor of course) It will probably be 3-4 years before I make saltwater, so they may need changing by then and I'd look at gell. I think a lot of sailors must be engineers, because we over-think everything!

I'm still re-thinking 8^) the house-to-engine neg- ground wire. I've reused a 2/0 awg from my Xantrex that was too short ( 6 inches too short, 89 bucks to replace, aagh! ) so combining will work, as well as grounding. That wire must way 20 pounds.

<brain>
If the switch is on "Both", and I crank the engine, pos+ house load will route through the switch-> starter and back thru the the big neg- wire, so I actually think the right place to connect it is on the neg- bus, so the shunt can measure it. That way the LinkLite (and DC panel meter) will see a draw when the key is turned.
</brain>

I bought the Linklite because the Xantrex Freedom 1800 charger doesn't support equalization. Buying the Link 2000 (aka Link 20 ) wouldn't have done more for me than the LinkLite

Ed, I have a book full of electrical doodles. I'm not sure I could put them all on 1 sheet of paper, I'd have to switch to Visio or some other schematic tool. Keeping the diagrams separate and small/simple was the best way to prevent brain failure.

 

[Mathurin]

I like your setup on your subpanel it kindda looks like mine , was it of any help ?
http://forums.hunter.sailboatowners.com/showthread.php?t=113352

 

[Mathurin]

In case you are loking at relocating your batteries, here's the my new setup, a lot easier to maintain, a lot more accessible then where they where before and a lot closer to both the main panel and the engine.

 

[sail_4_me]

Mathurin2 - I'm busted! 8^) Yes I looked at your design and stole lots of good points from it. My final setup is not as pretty, but just as functional. For some reason I can't jam all the wires in there and keep it really neat, but everything is properly crimped, heat-shrunk and labeled. ( I left 32" of wire between panel and back-panel, to allow me to pull the whole panel out and lay it flat. )

I like your battery placement, but I'm done with this project. That box would make excellent storage through....hmmm.

I've uploaded a diagram of the DC layout for those interested. It was done using OpenOffice Draw and exported to PDF format.

 

[Mathurin]

I like your diagram, here's the one I made to change my battery layout (it's half french half english, but mostly self explanatory, lol). I used autocad electrical, but your drawing looks more professional. Note that I have a dual output alternator and dual output charge control for the windgenerator so that is why I didn't use any charge sensing relay. Not on there is the battery meter. I tought about going with a xantrex link lite at first, but finally went with a good voltage meter, don't to have to play with it as much, and it does about the same job. When the voltage gets to a certain level, it's time to charge. The device is less expensive and you don't need a shunt (lol there are around 25 2/0 connector in my setup already, so I don't mind saving where I can)

 

[Mathurin]

Sail 4 me, I was wondering, is your boat a shoal draft ?

You say: Underneath the batteries is 18" or so to the bottom. I've got a Rule 2000 bulge pump under there on a float switch.

my boat is a shoal draft (4 foot) and there just enough space to put a battery in there...

 

[sail_4_me]

If I lie on my stomach I can just reach down far enough to touch the keel bolts. One previous owner put in 2 battery shelfs, and the last PO put in a 3rd one right underneath the grate at the bottom of the stairs. Thats a bad place for a battery, because you can see it through the grate. Even worse, underneath the grate is the access to the manual bilge sump, and its now blocked by a homemade fibreglass shelf ( which I will rip out sooner or later ). because its blocked, there was YEARS of crap sitting down there, rotting away. I spent a whole day cleaning out the bilge, and still have nightmares about the sewer smell.... yuck!

I have about 1.5 feet of space under the floor where the mast step is, and it gets deeper as you go back. I plan to move the shower sump ahead of the mast, and put the 3rd battery where the shower sump was.

I like your diagram too. I want to put in solar power and a wind generator eventually, so its nice to see another layout.

 

[sandpiper10471]

I am totally confused now by the AC grounding. Apparently all those green wires in the panel are supposed to be linked somehow to the engine, which of course on the original panel weren't, making them somewhat redundant I am sure. The engine has a yellow negative return to the common negative bus bar. If the AC grounds to the engine, then isn't it by default connected to the negative bus bar? And if that is the case, then why not feed a green AC ground from the panel directly to the bus bar? And that doesn't sound like a good idea. A bit of clarification would be appreciated.

 

[Ed Schenck]

I don't think there is an engine connection Bill. Here is a very simplified diagram from my original owner's manual: http://hunter.sailboatowners.com/in...&cat_id=38&aid=6732&page=article&mn=37-cutter . I have an inverter/charger between shorepower and the panel but it does not change the connections in the panel. There is a better diagram here somewhere and I will find and post it.

Here's what I was referring to, from the Hunter Owners Mods and not much help I am afraid: http://hunter.sailboatowners.com/images/kb/pdf/963.pdf . Scroll down.