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Mystery Electrical Problem

Discussion in 'Bertram Yacht' started by Mullide, Oct 12, 2010.

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  1. Mullide, Oct 12, 2010
    #1
    Mullide

    Mullide New Member

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    I have a mysterious electrical problem with my 1984 Bertram 38 Sport Fisherman. First, while crawling around below I noticed that the alternator on the port engine was hot to the touch. I removed the electrical connection to the alternator and it sparked. Later, while working on a strainer for the engine cooling system I got sparks when touching both the strainer and the port engine. I turned off every 12v breaker in sequence and checked for the sparks on the alternator lead and it was present with all of the breakers turned off. Has anyone run into something like this?
  2. K1W1, Oct 12, 2010
    #2
    K1W1

    K1W1 Senior Member

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    Hi,

    The lead you refer to might well be the positive and it is connected to the battery, you are getting a spark by touching it to negative through the engine block etc.

    Stick a volt meter between this wire and the block see if you get what the Voltage for the engine is, if it is positive and you have the red lead on it there should not be a - next to the reading.
  3. Pascal, Oct 12, 2010
    #3
    Pascal

    Pascal Senior Member

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    the hot alternator could be a bad alternator if single wire. the issue with the strainer is pretty serious, turn off all battery switches, not just breakers and check all connections, wiring, etc.. for chaffing
  4. Mullide, Oct 12, 2010
    #4
    Mullide

    Mullide New Member

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    In other words, this is normal? I assumed it was problematic and I needed to fix something.
  5. Mullide, Oct 12, 2010
    #5
    Mullide

    Mullide New Member

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    Pascal,

    I was going to turn off all the main breakers, ensure that the arcing stopped. This should make sure that the problem is on a circuit that is protected by a breaker. The fact that I turned off all the breakers one at a time and the arcing did not stop worries me. Either the issue may be on the charger side of the panel, between the battery bank and the breaker panel, etc.

    There are many connections in poor shape, lots of removed equipment, etc. I have no shortage of suspects. I thought the hot alternator was odd, though. I have never run into that.

    A dock neighbor suggested that it could be a bad ground somewhere, and a circuit is seeking a ground. I am not too sure about that idea.
  6. K1W1, Oct 12, 2010
    #6
    K1W1

    K1W1 Senior Member

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    Hi,

    I can assure you that the hot alternator when the engine isn't running and the sparks when you touch other engine room equipment ( It wasn't the lead off the alternator you were touching to the other things to get sparks was it?) is not a normal situation at all.

    If you turn off all breakers and there is still power there then the problem lies with something that is directly connected to the battery.

    What are the starter wiring and supply cables like?

    I ask this because this is somewhere where there is a direct heavy duty connection to the battery.

    Given what you have written so far I would not go away and leave the boat with the batteries on till you have found and sorted the problem

    If she is in the water and you need to leave her, rig up a bilge pump and float switch connected directly through an inline fuse to the battery and by pass the boats systems to provide your self with some level of protection in case something starts to leak.
  7. Pascal, Oct 12, 2010
    #7
    Pascal

    Pascal Senior Member

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    NO !!! it is absolutely not normal!

    dont know how much clearer i could have been. I once had a hot alternator and as i said, it turned out to be a defective one. you MUST disconnect it right away and get it fixed.

    if you still have sparks when touching the engine and the strainers, first turn off the battery switch. then i'd disconnect the main starter cables at the starters and re connect the batt switches.

    I have to say that based on your posts, I'm reluctant to make any troubleshooting suggestion since this is a SERIOUS situation and you dont' seem to be knowledgeable enough about electrical system.

    get a PRO to check this out right away before the boat burns or sink.

    I mean that.
  8. Mullide, Oct 12, 2010
    #8
    Mullide

    Mullide New Member

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    Thank you K1W1,

    I will elevate this issue from curious to urgent. I have added two new bilge pumps, but both are on breakers. She has been in the water since April and she is now floating. I have been on her almost every day and all other 12 V electrical systems are working normally.

    I replaced the batteries in May or June. This problem existed prior to and subsequent to the battery replacement. I will examine the main connections to the battery tomorrow morning.
  9. Mullide, Oct 12, 2010
    #9
    Mullide

    Mullide New Member

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    Pascal,

    Thanks. Your assessment of my knowledge of electrical systems is on the mark. I disconnected the hot alternator as soon as I discovered it. It was hot, but not hot enough to start a fire.

    I will jump back into this tomorrow.
  10. Marmot, Oct 12, 2010
    #10
    Marmot

    Marmot Senior Member

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    Did the alternator cool off after the mysterious wire was disconnected for a while? Which terminal on the alternator was this wire connected to?

    What sparked when you touch both the strainer and the port engine? Was it your fingertips? The wire you took off the alternator? A jumper wire between them? What sparked?
  11. Mullide, Oct 14, 2010
    #11
    Mullide

    Mullide New Member

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    Marmot,

    The image of sparks from my fingertips is impressive. Perhaps my ex wife could do that, but not me. I replaced the alternator today and this appears to have eliminated the problem of the hot alternator.

    I went to the rear of the port engine to recreate the sparking. It turns out the hot lead on the starter had lost it's boot and I had touched it while working on the strainer. I covered it and case closed. I don't have a dire emergency after all.

    All in all, a very good conclusion to the issue.