# need some tips on locating stray voltage..please



## michael.redmon (Aug 27, 2010)

I bought a 1987 bass tracker TX-17 last summer. I am pulling my hair out with something. I got a mild shock when touching the side of the boat while barefoot the other day. I think in boats that is a bad thing. I have spent about 5 long hours trying to pinpoint where in the heck the problem is. It appears that the ground wire runs from the battery to the bow, back to the steering wheel area for all the accessories. I have pinpointed which battery it is coming from (I have 3 batteries...#1 for the starter, #2 for the trolling motor in series, and #3 for the trolling motor and accessories). When i disconnect the negative lead on #3 the stray voltage does not exist. I have taken all fuses out of the fuse box and i still get 12 volts of voltage when touching a battery positive lead and the hull with my voltmeter. I have tried, as best as possible, looked for chafing of any wires. I do not see anything grounding to the hull.

I am at the end of my rope. Would you guys have any advice on how to troubleshoot this damn thing! Thanks in advance for tips you can provide.

Mike


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## promag (Aug 21, 2011)

Do a voltage drop test from each accessory that will tell you which wire that's causing it.. If you get less than 12v from any wire that's what is causing the problem don't power up the accessory just the battery and start at the battery to see the main supply first then to each accessory


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## I Fish (Sep 24, 2008)

You could also unhook each accessory one at a time until it stops. Then you'll know which accessory's wires are causing it. It could be caused by a screw or rivet through a ground wire, maybe a main ground wire going to a buss bar or fuse panel. If you can't figure out the source, I'd use a piece of string tied to the end and pull and inspect every wire on that battery's circuit. Stray current through an aluminum boat can be very bad due to electrolysis.


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## michael.redmon (Aug 27, 2010)

Thanks, i was going to pull the negative sides tonight and see if I can figure it out. I might just cut the main negative wire at the 2 spots I can see clearly...front of boat and near steer wheel to narrow it down....thanks and i will share on how to isolate.


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## fastwater (Apr 1, 2014)

Another thought... since you can't find bad wiring is it possible it could be the trolling mtr itself or foot control switch for trolling mtr shorted out internally backing feeding juice to the neg. wiring?

Since your #3 battery is hooked into the trolling mtr, think I'd start at disconnect the trolling mtr. and see what happens.


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## michael.redmon (Aug 27, 2010)

To carify: if i can read 12 volts between a hot lead and by touching the negative probe of the meter to the aluminum hull, does that mean i have a problem? 

I checked/diconnected everything except the negative wire from the starter battery to the engine starter. I didnt disconnect it but it got me thinking: if the negative wire from the battery goes to the starter connected to the outboard engine and the engine is connected to the hull then maybe it is ok to get 12V with the voltmeter.

I am so damn confused right now as to what is right and what isnt! I am going fishing either way tomorrow...if I didnt mess something up!


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## Misdirection (Jul 16, 2012)

Your ground should be bonded to your hull either directly or indirectly thru your motor. Going from the positive on your battery and to your hull for ground should show 12 volts. Somewhere you have a stray positive wire. If your problem goes away by disconnecting battery #3, your problem is somewhere in that wiring circuit.


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## Misdirection (Jul 16, 2012)

And let me clarify. Your problem is somewhere with a positive wire on battery #3's circuit. By disconnecting the ground in that battery, you simply broke the circuit.

BTW - was your boat plugged in and charging when this happened?


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## fastwater (Apr 1, 2014)

> Orig. posted by *michael.redmon*:
> 
> To carify: if i can read 12 volts between a hot lead and by touching the negative probe of the meter to the aluminum hull, does that mean i have a problem?


No! That does not mean you have a problem. That's normal. 
As *Misdirection* stated, your hull is acting as a ground due to the fact that your motor which is grounded by your battery cable is attached to your boat by metal clamps or bolts. Again, normal. 
So if you touch a hot wire with the + lead on your tester and touch the - lead to the hull, you will get 12/+ volts . 
FWIW...though the hull can act as a ground you should never use your hull as a designated grounding point for anything on your boat.

If you touched one lead of your tester to your hull and the other lead to the - post of your battery or another ground source even outside your boat and you read voltage, that would mean that you have a bare, hot wire laying against your hull somewhere putting voltage to your hull. Bad thing! Especially if you are not blowing the fuse in the circuit with the bare wire.

After re-reading your opening post, there is something not making sense to me. You stated #1 batt. is for starting. #2 and #3 are for accessories and trolling mtr. 
Then you said in that same post that when you disconnect #3 batt. the 'stray voltage' goes away. Were you referring to the 12v being the 'stray voltage' between the hull and the positive test point?


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## michael.redmon (Aug 27, 2010)

Thanks, yes, I got the shock while charging. Not charging I get 12 volt dc hull to battery.....is that ok???


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## I Fish (Sep 24, 2008)

michael.redmon said:


> and #3 for the trolling motor and accessories). When i disconnect the negative lead on #3 the stray voltage does not exist. I have taken all fuses out of the fuse box and i still get 12 volts of voltage when touching a battery positive lead and the hull with my voltmeter.


This is what leads me to believe it a leaking ground. If it was a stray positive, it would be like putting both leads of a meter on the positive terminal and show nothing.

Have you attached anything new, like rod holders, etc, anything that might have a screw that went through a wire?


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## Misdirection (Jul 16, 2012)

Yes it is OK to get 12v DC battery to hull while not charging.  I think your shock is coming from the 110v, not the 12v DC. Is your charger on board and if so are the screws holding it in place touching aluminum? They shouldn't be. On board chargers need to be isolated from an aluminum hull. Same thing with a portable. It shouldn't be touching or sitting on the aluminum hull.


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## michael.redmon (Aug 27, 2010)

Yes, the charger is attached with screws that go thru aluminum...

I really appreciate ur help


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