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Battery charging from prop shaft

Discussion in 'Technical Discussion' started by katieorielly, Aug 19, 2008.

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  1. katieorielly, Aug 19, 2008
    #1
    katieorielly

    katieorielly New Member

    Joined:
    May 25, 2008
    Messages:
    7
    Location:
    Kinsale, Ireland
    Anyone know of a battery charging device which can be engaged onto the rotating prop shaft when under sail?
  2. K1W1, Aug 19, 2008
    #2
    K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    7,394
    Location:
    My Office
    Hi,

    Yes, A belt driven generator or alternator could be used for this but shaft speed/pulley size is an essential part of any setup.
  3. Castlerock, Aug 19, 2008
    #3
    Castlerock

    Castlerock Senior Member

    Joined:
    Aug 30, 2006
    Messages:
    215
    Location:
    New England
    The issue that you need to look at with using the boats prop while the engine is not running is, are you getting proper lubrication to the transmission. Also think about the wear and tear on the transmission while sailing on a long passage. I have had good luck with the tow generators, they make 8 -12 amps of charge under normal conditions. These systems are made for what you want to do and are simple to use. I only have one suggestion, buy a couple of spare props and tow lines. There is nothing worse than loosing your charger to a pod of whales in the middle of the night, in the gulf stream where the phosphorescence illuminates it like a toy.
  4. Skiffy, Aug 19, 2008
    #4
    Skiffy

    Skiffy New Member

    Joined:
    Jun 22, 2005
    Messages:
    26
    Location:
    Plymouth
    Towed or shaft

    I'd go with towed, having used one for over 10,000nm in one year, to get a working set up for your shaft its going to cost something. The towed ones really do produce plenty to run all your electrics and you can also use them as a wind Gen when at anchor, or at least you can with the Aquair one I have.

    If your shaft has a water feed to lubricate and cool the stern tube bearing you'll be running it warm and wearing it faster with no water feed from the engine.