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Thread: Lazy alternator

  1. #1

    Unhappy Lazy alternator

    The alternator on my Volvo Penta 20/40 usually only starts charging after 3 engine starts. Sometimes it charges first time. I have checked belt tension, electrical connections and have even had the alternator serviced. It has been labelled a lazy alternator. Is it time to replace it?

  2. #2
    VicS is offline Registered User
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    Check the warning light circuit.

    It relies on the current flowing through the warning light to provide the initial excitation.

    The trouble might be in the electronic module in the control panel.

    You might replace the alternator and still have the same fault.

    You can't do much about the electronic module but check the wiring and all the connections between the D+/61 terminal on the alternator ( brown wire) the connections on the multi-way wiring harness ( pin 5) and the connection to the module.

    See the wiring diagram in the operators manual
    Sea Wych Owners Association: www.Seawych.org

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    TQA's Avatar
    TQA is online now Registered User
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    Occams razor sticky brushes?
    Monkey patching programmer [retired ]

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    Quote Originally Posted by TQA View Post
    Occams razor sticky brushes?
    In the good old days I often spent an enjoyable evening stripping down a dynamo in order to reset or replace the brushes but, in my experience, alternator brushes rarely give any trouble due to the smooth contact surface.

    As long as the drive is OK, an electrical problem seems most likely.

    Richard

  5. #5

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    I had a similar problem although I got an engineer to check it. I remember him saying the bulb in the warning light has to be 3 amp for some reason (Ithink it was refered to in the earlier post. The second alternator also needed the regulator changing (the little black box attached to it) as it was putting out the wrong voltage. It may not help a lot but then again.

  6. #6
    DaveS's Avatar
    DaveS is offline Registered User
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    Quote Originally Posted by RichardS View Post
    In the good old days I often spent an enjoyable evening stripping down a dynamo in order to reset or replace the brushes but, in my experience, alternator brushes rarely give any trouble due to the smooth contact surface.

    As long as the drive is OK, an electrical problem seems most likely.

    Richard
    I had an alternator brush wear out on my last car, but it had clocked up over 300,000 miles by then...

  7. #7
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    Has it suddenly got like this or has it always been the same while you have owned the boat ??

    Quote Originally Posted by hughevans View Post
    The alternator on my Volvo Penta 20/40 usually only starts charging after 3 engine starts. Sometimes it charges first time. I have checked belt tension, electrical connections and have even had the alternator serviced. It has been labelled a lazy alternator. Is it time to replace it?

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