Electrical issue question

[FuzzyGrub]

At this point, I’d remove all the accessory leads from the battery. Test each lead of each accessory for continuity to the hull. Check on the “diode” setting first for a direct short, and if no connection, go to a high range to look for a resistive short. My guess is the latter.

If that doesn’t find anything, start tying all the accessory grounds together, along with the positives, separately, but not connected to battery. Check the continuity between each to the hull, as you add each accessory. Something weird is happening.

You haven’t mentioned an onboard charger for the battery. Is there one? If so, has it been disconnected for testing?

 

[airshot]

I was thinking that when I read your post above. I don't have any dis-connects, but all circuit breakers and master panel power are on the positive.

I don't know how it would cause your problem though. Maybe some thought in the morning will help. Maybe feeding back through the motor ground?

All the inline fuses are on the positive side, even though the majority of my research shows the disconnect on the neg, I am beginning to think this might be the issue. I will try moving the switch to the pos and followup with more tests.

Thanks to all that have responded !

 

[Still Afloat]

This is really interesting now....does anyone realize how many videos, written articles and pkg instructions for disconnect switches have oposing statements about pos and neg wiring !!

It just proves that at least half of the advice on the internet is provided by people that don’t know what they are talking about.

 

[user 26281]

This is really interesting now....does anyone realize how many videos, written articles and pkg instructions for disconnect switches have oposing statements about pos and neg wiring !!

Electrically, disconnecting the current path is the same for either configuration.

Failure/Safety modes is totally a different story.

 

[user 26281]

This is really interesting now....does anyone realize how many videos, written articles and pkg instructions for disconnect switches have oposing statements about pos and neg wiring !!

Electrically, disconnecting the current path is the same for either configuration.

Failure/Safety modes is totally a different story.

This is really interesting now....does anyone realize how many videos, written articles and pkg instructions for disconnect switches have oposing statements about pos and neg wiring !!

 

[user 26281]

Totally disconnect starter battery - and + and recheck voltage.
Totally disconnect house battery - and + and recheck voltage.
Connect house battery + and recheck voltage : check to hull and to - battery wire.

 

[FuzzyGrub]

OK, after my 2nd cup of coffee, here is what I think is happening:

One or more of the devices ground wire(s) is touching the hull someplace. The parasitic device has to be in this loop. ie something that is always on. Be it one that was designed to always be on, such as radio or electronic bilge switch, or a device that has failed internally.

With the switch open you get a reading through the device to the negative post. When you close the switch, it completes a "short" and will not have a voltage reading, ie meter is not across a load.

All your ground wires are tied together at the disconnect switch and they all are grounded to hull thru that one or more neg wires touching hull.

If one of the positive leads to the accessories was touching the hull, the reading will be there, switch open or closed. If it was a positive side, resistive short to hull, would still see voltage switch open or closed.

If correct, when you move the disconnect to the postive side, you will not see +12V from neg post to hull, but highly suspect you will see +12V from positive post to hull, switch open or closed. ie the hull is tied to ground.

 

[user 26281]

One or more of the devices ground wire(s) is touching the hull someplace.

Some devices get/provide a ground from metal to metal contact.

 

[airshot]

Totally disconnect starter battery - and + and recheck voltage.
Totally disconnect house battery - and + and recheck voltage.
Connect house battery + and recheck voltage : check to hull and to - battery wire.

Did that test yesterday, no difference

 

[airshot]

OK, after my 2nd cup of coffee, here is what I think is happening:

One or more of the devices ground wire(s) is touching the hull someplace. The parasitic device has to be in this loop. ie something that is always on. Be it one that was designed to always be on, such as radio or electronic bilge switch, or a device that has failed internally.

With the switch open you get a reading through the device to the negative post. When you close the switch, it completes a "short" and will not have a voltage reading, ie meter is not across a load.

All your ground wires are tied together at the disconnect switch and they all are grounded to hull thru that one or more neg wires touching hull.

If one of the positive leads to the accessories was touching the hull, the reading will be there, switch open or closed. If it was a positive side, resistive short to hull, would still see voltage switch open or closed.

If correct, when you move the disconnect to the postive side, you will not see +12V from neg post to hull, but highly suspect you will see +12V from positive post to hull, switch open or closed. ie the hull is tied to ground.

I will be reading this a couple more times but I think I get your idea. Will be making some changes and doing some additional testing later today. Wife's doctor appointments sure come at the worst times !!

 

[airshot]

Some devices get/provide a ground from metal to metal contact.

That I understand, but looking at what I have, I don't see any that way. Everything appears to have a wire for neg to battery and a red pos wire. Going to run the smarter tests later today and see what I have, thanks !!

 

[airshot]

Swapped the switch to the pis post in the battery and hull remains charged all the time no matter what the switch position is. Did notice some extra sparking on a pair of wires, so I disconnected them and the 12v charge to the hull disappeared completely. I am sure that harness goes to the dash accessories so after wife's doc appt, I will get under there and see what his going on. Any other ideas feel free to mention them....thanks !

 

[LaqueRatt]

OK, this shouldn't be all that hard. You have a connection between your pos terminal and the hull. Almost for sure a wire has been pinched or has a void in the insulation. To find it disconnect the battery and one by one check each wire for continuity between it and the hull. One of your connections is going to show no resistance, which means that's the one that is shorted out to the hull. Once you find the circuit with the problem it's just a matter of inspecting or replacing that wire.

 

[FuzzyGrub]

That I understand, but looking at what I have, I don't see any that way. Everything appears to have a wire for neg to battery and a red pos wire. Going to run the smarter tests later today and see what I have, thanks !!

If it has both wires, generally means that the chassis should not be attached to the ground. It still might be.

 

[flatheadsteve]

Swapped the switch to the pis post in the battery and hull remains charged all the time no matter what the switch position is. Did notice some extra sparking on a pair of wires, so I disconnected them and the 12v charge to the hull disappeared completely. I am sure that harness goes to the dash accessories so after wife's doc appt, I will get under there and see what his going on. Any other ideas feel free to mention them....thanks !

It's almost certainly a chaffed wire touching the hull or something metal that attaches to hull. Could be the slightest of nicks too.

 

[FuzzyGrub]

Swapped the switch to the pis post in the battery and hull remains charged all the time no matter what the switch position is. Did notice some extra sparking on a pair of wires, so I disconnected them and the 12v charge to the hull disappeared completely. I am sure that harness goes to the dash accessories so after wife's doc appt, I will get under there and see what his going on. Any other ideas feel free to mention them....thanks !

Do the continuity test on those wires to the hull. Once verified, can than isolate further. Depending how your wiring is run, probably best to check at those devices next.

 

[airshot]

There are a pair of wires that go to the dash for accessories I think. When those are not connected to the battery, no charge in the hull. Now I need to get up under the dash and see where the issue is. What a ball of spagetti !!

 

[Bailey Boat]

I have a FIRM policy about boats, unless I wired it I strip ALL wires out and rewire EVERYTHING myself. Always home run to my fuse panel, I never use in line fuses................ but that's just me......

Life is too short to chase electrical gremlins that someone else left behind..... And don't discount the garage monkeys changing things while you sleep.....

 

[Still Afloat]

I’m trying to get the new to North River Mariner on the water by mid June for vacation. The factory wiring is mostly undisturbed but, the previous owner’s wiring is a real sh#t show. The highlight was two runs of 14 AGM solid THHN wire from the reserve battery and main battery to the Downrigger power plugs. Those are 30A circuits on 14 gauge solid wire that is intended to be used in conduit. It should have been 10 gauge stranded and sheathed wire. To top it off the wires were tied wrapped to the fuel lines and fuel tank filler hose.

 

[LDUBS]

I’m trying to get the new to North River Mariner on the water by mid June for vacation. The factory wiring is mostly undisturbed but, the previous owner’s wiring is a real sh#t show. The highlight was two runs of 14 AGM solid THHN wire from the reserve battery and main battery to the Downrigger power plugs. Those are 30A circuits on 14 gauge solid wire that is intended to be used in conduit. It should have been 10 gauge stranded and sheathed wire. To top it off the wires were tied wrapped to the fuel lines and fuel tank filler hose.

They must of had some romex laying around. Stuff like that makes you want to check everything the PO might have touched.