STRAY CURRENT Issues, need help!

[senormechanico]

Originally Posted by deblen

Wooden boat-"ghost" voltage-first time I have heard the "ghost" term but is appropriate. Especially with super sensitive digital volt meters.
Try an analogue meter.
or,try pushing one digital meter probe into hull wood and other probe to both bat. terminals & alum. box.
If bats. have been sitting on wood for a year,you probably have some "microamp" leakage due to normal dampness on bat. cases & wood platform/box.
Remove bats. Wash the bat cases & wood box/wood platform with soapy water.Let dry for a couple days & paint inside wood box/wood platform with good gloss oil paint.
Use a sheet of thin plastic on top of wood platform before setting bats. back in wood box.

Cheers/ Len

I think Len is onto the possibility.


When you thoroughly washed the batteries and aluminum box, did you thoroughly wash the BOTTOMS of those batteries?

[Bowdrie]

Originally Posted by deblen

Wooden boat-"ghost" voltage-first time I have heard the "ghost" term but is appropriate. Especially with super sensitive digital volt meters.

Yeah, on occasion I've detected what is commonly called "phantom" voltage.
It would show-up on DC wires that were bundled with active AC wires.
Transformer effect, small potential showing but no current detectable.

[Fiso]

Originally Posted by s/v Jedi

Please describe the circuit return path that electrocutes someone with an isolation transformer that didn’t ground their inverter?

Also, it helps to know what your background is, are you an electrical engineer? I am highly surprised that you can draw a diagram of an unknown boat.

Well, to point 1. I hope that you are NOT advocating installing an inverter without a ground. The return path given a failure in the inverter then would be YOU.

To point 2: I do work in the field and quiet a long time. Currently as an engineering manager. Not a self-proclaimed Marine specialist of any kind nor to know ABYC guidelines specifically vs ABCDEFG. The intent was to assist with the OPs original question of finding his stray 9Vdc he was concerned with, as he requested. Is that not the point here? The simple line drawing is far from an electrical design, but a depiction of his original word description of his system and problem. Looks accurate to me from reading his words and I asks him to correct me if I missed anything.

As well, I advocate (advocated originally) that everything in the boat (AC/DC/Bonding) should be tied to a common electrical return point (Bus Bar), of which I still do. I think even ABYC does however; there is a hotly debated conversation about a floating DC system. You may want to review my post again, as I still believe it accurate. As for the isolation Xfmr, I was speaking off the top of my head, but attached is an ABYC drawing. Looks also as I described. Again, no self-proclaimed boat wiring expert, don’t even play one on the interWebs, but I believe that what I described for that is also accurate. Check it out. (attached). That’s is how the isolation part, “Isolates”…

Just trying to assist the OP in his request to isolate his +9Vdc source. I described how I would go about it if it were my search. Up to him and his maintenance personnel in how to use it or not. Good luck with your search Pedro.

[s/v Jedi]

Originally Posted by Fiso

Well, to point 1. I hope that you are NOT advocating installing an inverter without a ground. The return path given a failure in the inverter then would be YOU.

On a boat, disconnected from shore power? You are completely wrong. Describe the circuit! You touch L, it goes through your body to where? How does that get back to the ungrounded N of the inverter?

BTW, ABYC is working on isolated power systems, I hope their documents come out soon.

[Fiso]

I will let Blue Sea Systems describe for you sir.

https://www.bluesea.com/support/arti...ttery_Chargers

[s/v Jedi]

Originally Posted by Fiso

I will let Blue Sea Systems describe for you sir.

https://www.bluesea.com/support/arti...ttery_Chargers

As expected.

[Bowdrie]

Originally Posted by s/v Jedi

BTW, ABYC is working on isolated power systems, I hope their documents come out soon.

Yes, it's not 1964 anymore, we have better ways of protecting the metals in/on boats and the people in the boat or in the water from any electrons that try to take a forbidden path.

[caffel]

Re: Ps2, battery condition, sealed batteries can be hard to test. On our roobottics team we we use a tester similar to thiis one:
https://cloreautomotive.com/product/ba9/

Which yields state of charge, state of health and internal resistance.

[Fiso]

Originally Posted by s/v Jedi

As expected.

Read the article sir....

“As expected,” Jedi, is not an answer to help anyone. You haven’t helped the OP once in this… Sorry Pedro…

Jedi. You guys want to wire your boats as you wish, then have at it. Not my electrical problem, nor my problem to school you/educate you/convince you about it. I won't be wiring mine with your two-wire ungrounded scheme. I want the protections to work… What aggravates me about it all is your telling everyone else it's OK, and it's not. Saw you beating poor people up in past post since 2009, but not quite so easy with me my friend. My actual specialty in life is R&D engineering, and I can fail your stupid circuit in a bazillion ways, that electricians like you look at me after the fact with the dog pumped me in the butt eyes... My answer is aways, Did ya do XXX like I said, and the answer is always back, “we got it to work”… until it didn't. That answer isn't acceptable on my boat when the possibility is a fire or electrocution hazard or injury at sea. I don’t engineer for when it works, but when doesn’t… Kind of too late for that good ol boy engineering at that point, and you’re advocating that at this moment. STOP IT… I can fail an open, ungrounded two wire AC system in so many ways it will make your head spin. The fact you can’t see that is the danger…. (well, not for me, I am not going to do it!!!)
If you really want to prove your point in an Electrical Engineering way, and I have seen you have spent some time capital on it over the years (wrongly) beating innocent people up over it, then quit taking up the Ops time making pissy quips, and start a board for this. Invite me, and all your electrical cronies, and all the EE’s, and PE’s you can muster to that forum. We can talk about ships 2 and 3 phase isolated electrical systems vs. your ridiculous ungrounded AC SCHEME ON A SAILBOAT.. Let’s see how you fair in that discussion…. I am going to bet you will be a piss stain and I may learn marine systems don’t abide by the laws of physics. Your input can surely shine here and I can’t wait to hear your astute ungrounded theory among that crowd. I bet many boat owners would be interested in the outcome of this conversation.

[s/v Jedi]

Originally Posted by Fiso

Read the article sir....

“As expected,” Jedi, is not an answer to help anyone. You haven’t helped the OP once in this… Sorry Pedro…

Jedi. You guys want to wire your boats as you wish, then have at it. Not my electrical problem, nor my problem to school you/educate you/convince you about it. I won't be wiring mine with your two-wire ungrounded scheme. I want the protections to work… What aggravates me about it all is your telling everyone else it's OK, and it's not. Saw you beating poor people up in past post since 2009, but not quite so easy with me my friend. My actual specialty in life is R&D engineering, and I can fail your stupid circuit in a bazillion ways, that electricians like you look at me after the fact with the dog pumped me in the butt eyes... My answer is aways, Did ya do XXX like I said, and the answer is always back, “we got it to work”… until it didn't. That answer isn't acceptable on my boat when the possibility is a fire or electrocution hazard or injury at sea. I don’t engineer for when it works, but when doesn’t… Kind of too late for that good ol boy engineering at that point, and you’re advocating that at this moment. STOP IT… I can fail an open, ungrounded two wire AC system in so many ways it will make your head spin. The fact you can’t see that is the danger…. (well, not for me, I am not going to do it!!!)
If you really want to prove your point in an Electrical Engineering way, and I have seen you have spent some time capital on it over the years (wrongly) beating innocent people up over it, then quit taking up the Ops time making pissy quips, and start a board for this. Invite me, and all your electrical cronies, and all the EE’s, and PE’s you can muster to that forum. We can talk about ships 2 and 3 phase isolated electrical systems vs. your ridiculous ungrounded AC SCHEME ON A SAILBOAT.. Let’s see how you fair in that discussion…. I am going to bet you will be a piss stain and I may learn marine systems don’t abide by the laws of physics. Your input can surely shine here and I can’t wait to hear your astute ungrounded theory among that crowd. I bet many boat owners would be interested in the outcome of this conversation.

You are hilarious. How sorry you will be about this post, that you can’t delete, after you find out how isolated systems are in use where safety is of the highest priority, like clean rooms, operating rooms and commercial shipping, as well as on the desk of electronics engineers to prevent electrocution while repairing equipment. And then when ABYC publishes their upcoming documents on this, you will probably stamp your feet in anger.

Also, your personal attacks and calling me a piss stain are not allowed on this forum and can get you banned. I won’t report you but this is the last time I read anything from you.

[Fiso]

Jedi. Poor choice of wording. Not trying to call names specifically personal to you. I think that I have been rather nice with this discussion, but I do not want people reading this and following clearly poor advice… The others you have berated on this subject (I read some of your other electrical theory posts) didn’t have the ability to dispute you. I do…. ABYC expert? Nope. Boat electrical design expert? Nope. Well educated in this stuff? Yep, and better than 40 years seeing the un-fallible circuit, fail…

What I am suggesting is that in a room full of electrical system designers if you care to open a forum for that discussion, You, me, we, many others’ opinions, would be inconsequential to that discussion (i.e., an insignificant stain (better word choice)). I know that I do not design electrical power systems specifically for a living nor do the people here reading and looking for these answers. I do design and maintain the electronic management and protection systems that supervise and operate them. I have also never said that it can’t be done, but in the case of the Ops boat and his questions, and IMO the poor advice he was being given to isolate his AC electrical system, that it should not be done in this use-case. I have presented drawings, articles, standards, etc. to support my opinion. I have not seen any examples from yourself, just unsupported corrections. If, as you say, the ABYC is coming out with an isolated AC, as in Alternating Current, not DC system, for Non-commercial boats. Well, I am going to have to see that. Want to post a link?

I also continue to say that the guys that specifically design these electrical systems for a living, employ many sophisticated topologies, some very specific to the industry they serve, floating, non-floating, earth tied, etc., but they all come with likewise, sophisticated protection and management systems and skilled electricians to maintain and service them. I would be extremely surprised to hear any EE or PE say that NO protections or management is acceptable. It’ll never happen isn’t how this should ever be viewed, because sometimes it does happen, and in ways we never even dreamed possible. Public operated, NON-commercial systems with non-electrical persons as operators, of which I would consider a sailboat, including the Ops, to be just that in most cases, need to protect the operator IMO. It is built into the device itself, eeer, unless you don’t connect it. Throw in some salt water and remote locations away from someone to restart your heart for you, and it not only needs to be there, but for my boats, must be there…As I am no more the boat electrical systems police than you, I leave all to choose how they wish to do their own and read these words for what value they provide for them. Have fun.

[Bucket]

Regarding voltage on the Alu cabinet: if you are reading no continuity, then nothing to worry about. It is one of two things; either there is infinitesimal leakage due to surface moisture, or you have unintentionally created a battery with the stacks of different material. If it bothers you, tie the cabinet to the negative post of the battery with a short length of 18 gauge (or larger wire) to a hinge or just use a self-tapping screw.

Leakage from your AC ground to seawater when hooked up to shore power is really the main thing to worry about as it will greatly speed up electrolysis of any metal in contact with that seawater. There are great products to prevent this. They are usually Schottky diodes that limit the difference in potential to about 0.3V, which is less than what is required for electrolysis between metals. Pretty sure that BlueSea Systems sells one.

Mike (EE)

[Bowdrie]

We shouldn't be using the term "electrolysis" in relation to a boat.
On a boat It's a reaction that occurs somewhere between extremely rare to nonexistent.
I have used "electrolysis" several times to remove rust from cast iron machinery parts.
It's a system in which the anode is made positive and the metal you want to save is made negative, both submerged in a soda-water solution with DC applied to the respective parts.

[s/v Jedi]

Again: https://boatzincs.com/categories/too...electrode.html

You check voltage against a silver chloride reference cell, not against a battery terminal that shows no conductivity to a metal surface.

Modern DMM’s have such high input impedance that saying boo! to it’s probes will show voltage. If you want to measure anything that way then you need a pull-down resistor. But you don’t want to do that, you want the reference cell to measure against.

[Bucket]

Originally Posted by Bowdrie

We shouldn't be using the term "electrolysis" in relation to a boat.
On a boat It's a reaction that occurs somewhere between extremely rare to nonexistent.
I have used "electrolysis" several times to remove rust from cast iron machinery parts.
It's a system in which the anode is made positive and the metal you want to save is made negative, both submerged in a soda-water solution with DC applied to the respective parts.

noun
noun: electrolysis
1.
CHEMISTRY
chemical decomposition produced by passing an electric current through a liquid or solution containing ions.


This is literally the definition of what happens on a boat.
Chemical decomposition - check.
Electric current - check
Solution containing ions (seawater) - check