Reply
 
Thread Tools Display Modes
 
Old 08-30-2016, 10:14 AM   #1
Senior Member
 
City: Pensacola, FL
Country: USA
Vessel Name: Sea Triscuit
Vessel Model: Transtar 50'
Join Date: Dec 2015
Posts: 177
Stray 12v voltage - where to begin?

I was checking for voltage to the shower sump pump and found that with the 12v breaker off I was getting -2.7v. With the breaker on I was getting 13.2v. I'm assuming there should not be any voltage with the breaker off? I'll have to trace the wire, but I believe the pump is on its own circuit and comes direct from the panel. To fix it, check the breaker for voltage at the panel? If no stray voltage at the panel, pull the old wire and run new wire?

Any common causes of this? Is it unusual?

Thanks!
__________________
Advertisement

__________________
SeaTriscuit.com - Abandoning the real world for St Thomas with a Craigslist trawler, little experience, and two cats.
Panhandler is offline   Reply With Quote
Old 08-30-2016, 02:08 PM   #2
Guru
 
caltexflanc's Avatar
 
City: North Carolina for now
Country: USA
Vessel Name: Small Incentive
Vessel Model: Boston Whaler 130 Sport
Join Date: Aug 2011
Posts: 3,463
Is the pump connected to a float switch? A ground trace would be in order as you may have another device that some PO put on the ground circuit. (Given you say it is showing "negative" voltage. Check some other devices for CB on/off voltages.
__________________

__________________
George

"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"
caltexflanc is offline   Reply With Quote
Old 08-30-2016, 02:19 PM   #3
Senior Member
 
Russell Clifton's Avatar
 
City: Marysville, Wa.
Country: usa
Vessel Name: Sea Fever
Vessel Model: Defever 49 RPH
Join Date: Sep 2012
Posts: 249
Might try this. Turn off your 12v battery switch so all of the battery voltage is turned off on the boat. Check to see if you still have the 2.7v. If it is gone, turn battery switch back on, start turning off 12v breakers, checking for the 2.7v after each one until you find the one that is supplying the 2.7v Now you should know which system is supplying the voltage. Not exactly sure what to do from this point. Good luck.
Russell Clifton is offline   Reply With Quote
Old 08-30-2016, 02:54 PM   #4
Senior Member
 
City: Pensacola, FL
Country: USA
Vessel Name: Sea Triscuit
Vessel Model: Transtar 50'
Join Date: Dec 2015
Posts: 177
Thanks, good ideas!

Caltexflanc, there was not a pump switch connected when I tested the voltage.
__________________
SeaTriscuit.com - Abandoning the real world for St Thomas with a Craigslist trawler, little experience, and two cats.
Panhandler is offline   Reply With Quote
Old 08-30-2016, 07:27 PM   #5
Veteran Member
 
Panacea123's Avatar
 
City: Cape Coral, Fl
Country: Usa
Vessel Name: Panacea
Vessel Model: Novatec 42 Sundeck Trawler
Join Date: Jul 2016
Posts: 61
Quote:
Originally Posted by Russell Clifton View Post
Might try this. Turn off your 12v battery switch so all of the battery voltage is turned off on the boat. Check to see if you still have the 2.7v. If it is gone, turn battery switch back on, start turning off 12v breakers, checking for the 2.7v after each one until you find the one that is supplying the 2.7v Now you should know which system is supplying the voltage. Not exactly sure what to do from this point. Good luck.
Good advice!
If when the batteries are totally disconnected you still read voltage you have a stray current issue.
Put one lead of you meter on neg connector other in sump water, if you read voltage, its stray current, check bonding system and zincs
Panacea123 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 11:43 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012