DC schematic and main battery cables

[PeterF]

I’m trying to create an electrical schematic of a friend’s 1985 Krogen Manatee. I’m focusing on the core DC components (e.g. batteries, charger, major switches and loads). My question is regarding the 2 heavy gauge cables connected to terminals 1 & 2 of the battery selector switch on the main electrical panel. Due to how these cables are routed, I cannot visually trace them. I assumed they go directly to the positive posts of the 2 batteries in the stern end of the engine compartment, without connecting to anything in between, but apparently that is not the case (got voltage with both ends disconnected). Does anyone know what might be connected between the battery selector switch and the batteries?

Does anyone know where I might obtain an electrical schematic for this boat, at least for the core DC power components?

 

[meridian]

Remember, you see one Krogen, you've seen one Krogen. Especially after 30 years although a diagram will give you a starting point.


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[meridian]

Call Krogen directly. They should have the originals.


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[Brooksie]

I assumed they go directly to the positive posts of the 2 batteries in the stern end of the engine compartment, without connecting to anything in between, but apparently that is not the case (got voltage with both ends disconnected). Does anyone know what might be connected between the battery selector switch and the batteries?

Don't know about Krogen but almost everything should be off when battery switch is off. I say almost because there are a few 24/7 items that you may want on even when the main switch is off. Bilge pump/s, anchor light, battery charger, solar panels, wind generator are a few I can think of. These could have their own 24/7 fuse/switch panel.
I don't know exactly what you mean by "got voltage with both ends disconnected" or if there are any of the above items aboard that could be backfeeding the disconnected wire. For instance, battery chargers have capacitors in them that can give a strange reaction on a digital meter from their stored charge.

 

[DavidM]

In my limited experience, asking for an electrical schematic of a 30 year old boat is a worthless proposition. And even if you had the factory schematic, the POs probably modified it.


Yes, normally the #1 and #2 switch terminal would go to the #1 and #2 battery. Are you sure that you disconnected both ends and not one wire at the switch and another at the battery? Try disconnect both at both ends and see what you get.


But maybe one or both go to a fuse or breaker panel that feeds loads that should never be disconnected like bilge pumps, CO detectors, etc.


My Mainship Pilot 34 and the 34T trawler before it was wired this way. But that doesn't explain why you have a voltage with both ends disconnected. Maybe you have a small DC leak that is back feeding from the device like a bilge pump. Digital meters put very, very little impedance on the circuit being tested, so it doesn't take much of a leak to read full voltage.


Try connecting a small light bulb to the wire and ground the while it is disconnected at both ends. I will bet it won't light.


David

 

[PeterF]

Brooksie and djmarchand, you're both right about there being some things that are never disconnected; in this case the bilge pump is connected to the #2 terminal on the switch and thus always has power regardless of the position of the battery selector switch. As djmarchand suggested, I had both ends disconnected on the cables that go from the batteries to the switch, and thus everything (bilge pump, charger) should have been disconnected from those cables. Meridian, I agree, and was hoping another Krogen owner might offer up the schematics. Like djmarchand, I had my doubts about Krogen still having the schematic available, but I'll try anyway as you suggested.

 

[FF]

The thinking on how batts should be managed has changed in 30 years.

Find a schematic on line for a boat that will be operated in a similar manner as the Krogen.

Cruiser , Dock condo, weekend anchored out ?

 

[DeniseO30]

30 years is old, there are wiring harnesses available for boats,
Building a good battery system is important but not difficult

Outfits like Blue sea have all kinds of diagrams,. And there actually is a marine wiring colour code!

 

[PeterF]

...there actually is a marine wiring colour code!

DeniseO, you have me intrigued - while I doubt that this boat adhered to it, where would I find the marine wiring colour code?

 

[dhays]

Just a thought... Instead of helping diagram what is, maybe you could help him diagram what should be? I know that you need to figure out what is in place, but if the boat is wired in an obsolete way, and the owner wants to I,prove it, maybe now is the time? For example, are their fuses on the battery cables near the battery and what about those 24/7 items? They should be fused as well to protect the wiring.

 

[DeniseO30]

If the boat was built by a MFG is most lthey most likely did use the code Pete.
Easy to find.ABYC Color Codes for Boat Wiring | Boating Magazine

Here's the wiring dia from my old sailboat. you can see there that the colors did go with the code .

The back of the engine panel.. "before"

 

[DeniseO30]

And..

not in order.. sorry.

 

[DeniseO30]

Just a thought... Instead of helping diagram what is, maybe you could help him diagram what should be? I know that you need to figure out what is in place, but if the boat is wired in an obsolete way, and the owner wants to I,prove it, maybe now is the time? For example, are their fuses on the battery cables near the battery and what about those 24/7 items? They should be fused as well to protect the wiring.

I have found other boats from the 80s even late 70s have allot in common with the "code" I'm by no means a marine electrician but found all this stuff very helpful. Helped my bro in law with his 16 ft boat from the 70s .. yup. wasn't much there but the colors were right!

Krogen... well to be determined need photos!

 

[FF]

Wired directly to the battery is the "always hot bus" which is protected and controlled with a fuse.

The only items I might have there is the Bilge high water alarm and a burglar alarm if fitted.

Pumps should be controlled from the normal rotary switch and CB for of/on.

 

[angus99]

I'm working with ABYC-certified electricians via email to help redesign major portions of my 12-volt and AC systems, adding a new inverter-charger, alternators, external regulators, large house bank, cabling, circuit and chafe protection and on and on. One of the techs is a systems designer who did a simple drawing of the new major circuits (I'll do a more complete version when it's finished). I'm doing the work myself and will have a pro idiot check me. It's real work, but I'll have the system I want, will understand the system I've got and a lot of the concerns from the age of the wiring and components, as well as PO issues, will be gone. This is some of the new stuff--again far from finished.

 

[DeniseO30]

Nice work Angus!

 

[psneeld]

I will say as many boats are rewired, they lose the color coding and become wired with flat duplex (dc) and triplex (ac) sheathed cables and are labeled.

Many feel this is an easier way to go when rewiring over new instals, though labeling becomes more important to a degree.

 

[FF]

"though labeling becomes more important to a degree."

With nearly a dozen wire colors , and differences in EU and USA labeling is a simple answer.

Any big electrical supply house will have a book of numbers that can be attached (stuck on) wiring as you go.

I prefer to match the wire number with the CB number as well as the user.

When light 3 8 fails the owner looks for the "3" service panel and "8 CB" .

The numbering should be done near the end of the wire (leave enough wire for a new terminal end ) and about a foot away , so 20 years later there will still be information.

Majic scotch tape or clear shrink tubing over the numbers will assist over the decades.

The book of numbers I use has 0-9 on pages , so any number can be created.

Here is a different style,

http://www.toolfetch.com/brady-wm-1...rm=BR-111838&gclid=CNH6uKna7c0CFcdehgodJVMITw