12 volt dillemma

Discussion in 'Electrical Systems' started by gasdok007, Apr 16, 2006.

  1. gasdok007
    Joined: Jul 2004
    Posts: 25
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: melbourne,fl

    gasdok007 Junior Member

    I'm trying to troubleshoot an electrical problem - aluminum hull, twin honda outboards, two batteries.Boat is out of water on trailer. Port battery keeps draining and dying.This is also the housekeeping battery,but with battery switches off there is no current draw.I'm thinking that the engine rigging may be wrong.The port ignition must be on in order to power the starboard ignition,and when the battery ground is connected to the motors (or either motor) ther is continuity between the + terminal and the metal hull( my test light goes out when I disconnect the negative to the motor).My understanding is that the negative ground should be isolated from the metal hull.Do the mounting brackets tie the ground to the hull or is something else wrong? Any thoughts appreciated.
  2. longliner45
    Joined: Dec 2005
    Posts: 1,629
    Likes: 73, Points: 0, Legacy Rep: 505
    Location: Ohio

    longliner45 Senior Member

    have you had the cells checked in the one battery ? even new ones can be bad
  3. Tim B
    Joined: Jan 2003
    Posts: 1,438
    Likes: 59, Points: 0, Legacy Rep: 841
    Location: Southern England

    Tim B Senior Member

    Sounds like something is shorting the battery. A simple check is to disconnect one side of the battery and put an ammeter in the circuit (at the battery). If there is no current flowing at the battery, take it out and see if the same thing happens on the work-bench at home.

    Tim B.
  4. gonzo
    Joined: Aug 2002
    Posts: 16,354
    Likes: 1,407, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The hull is connected to the negative ground. That is the correct setup. The test light is not showing continuity but voltage difference. That is correct too.
  5. solrac
    Joined: Feb 2006
    Posts: 138
    Likes: 5, Points: 0, Legacy Rep: 42
    Location: 34'54"35"47S - 56'07"48"98W

    solrac 100% sudaca

    maybe cheapest solution, install a 2 pole-circuit breaker & isolate both positive + negative battery pins...

  6. gonzo
    Joined: Aug 2002
    Posts: 16,354
    Likes: 1,407, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    If the battery is draining, you need to find the problem. It shouldn't happen if the system is installed correctly. What may appear to be a cheap and fast solution could create a worse more expensive to repair problem.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.