Starter motor as a main motor?

Discussion in 'Hybrid' started by mitchellleary, Jul 23, 2015.

  1. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Golf carts typically use more HP motors than your needs, but might be worth a look too. This typically are 36 or 48 VDC units.
     
  2. mitchellleary
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    mitchellleary Junior Member

    Hey blisspacket,

    Thanks for those recommendations. The site for goldenmotor is amazing! As I've found some great motors on there that will give a higher voltage and that could do the job for me.
    The forum you posted is also very informative so that alot for that!

    Cheers!

    Mitch

     
  3. mitchellleary
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    mitchellleary Junior Member

    Thanks again PAR.

    I've found a few Golf Buggy motors that look pretty good thanks to your recommendation so I'm going to look into it a bit more but this could be a very good option!

    Nice one!


     
  4. mitchellleary
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    mitchellleary Junior Member

    Thanks Tom!

    I've now realised thanks to the replies on my post that upping the voltage is the way to go. Would you say that the name of the game is; "The higher the voltage, the better"? Or not necessarily?
    I ask because I've found some Golf Cart motors that are 72V.



     
  5. Barry
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    Barry Senior Member

    Is a surface drive a good idea for such a low speed and hp?
    My understanding is that surface drive props are extreme pitched as only one or maybe one and a half blades are in the water at any one time and are operating at high speeds so that the upstream side of the blade has a high initial velocity.

    Baeckmo?
     
  6. DCockey
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    DCockey Senior Member

    My recollection is that higher than 48 volts is usually considered as potentially hazardous to people, and a higher level of protection against human contact is needed.
     
  7. mitchellleary
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    mitchellleary Junior Member

    Thanks DCockey.

    Thanks to your point, I've looked into it and you're right that 72V and above is considered dangerous so I think I will be sticking with 48V.

     
  8. mitchellleary
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    mitchellleary Junior Member

    Thanks for the reply Barry.

    What would you recommend would be a good alternative to surface drive in my case?

    Cheers

     
  9. blisspacket
    Joined: Jun 2005
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    blisspacket Junior Member

    I'm playing with surface drive at the moment, with no conclusions. I like what I see on youtube with the dragontail drives and the speeds they achieve. When you contemplate a fully immersed prop AND a trolling motor in front of it, there has to be enough electrical energy taken by the motor an d wasted.
    I have a 3/4 drive shaft in a 2" tube coming out the transom some two feet, with various props trialed. Best so far on these surface driving props is 7 mph, 48 volts, 50 amps.

    To compare: with a Torqeedo Cruise 4 on the same boat, 100 pounds more in cargo, I got 9.5 mph at 48volts using 90 amps. Nothing really conclusive here. In a few weeks I should be able to raise the output on the surface drive to 130 amps. I'll post the results.
     
  10. Barry
    Joined: Mar 2002
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    Barry Senior Member


    The original post states that you are wanting to couple a surface drive prop with an electric low horsepower motor.

    I have seen several Arneson drives and the prop blade pitch is high. All the ones that I have seen were twins so each props tendency to pull the transom in the direction of the rotation is counter balanced from the other.

    With a normal prop with all blades immersed there is less
    tendency for this transom "walk"

    With a surface piercing prop with say one blade in the water, this effect is amplified

    The higher the pitch, the more the effect.

    Is the goal being able to run in shallow water or trying to achieve some efficiencies using a surface prop?

    My original question was to ask contributors if a low speed low horsepower surface piercing drive was feasible.

    I don't think that if you had a prop from say a 4 horsepower
    outboard and just lifted the engine so only one blade was in, that you would gain anything as there is so much less blade area to create thrust. Hence a surface prop needing a steeper pitch.
     

  11. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Blisspacket might have unknowingly found your 12 or 24 volt motor source problem

    There are lots of ELECTRIC trolling motors that are constant duty and not very expensive. As these motors are designed to run immersed, you might run into cooling problems if your configuration keeps the motor above the water
     
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