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Electric Boat

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  • Jim Goeckermann
    This is an interesting thread, and I have been thinking along these lines myself, though I must admit that I have reservations. Since I live in a totally
    Message 1 of 4 , Apr 30, 2002
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      This is an interesting thread, and I have been thinking along
      these lines myself, though I must admit that I have
      reservations. Since I live in a totally solar house powered by
      sixty large photovoltaic panels, I have a little experience
      with this sort of thing. With a 1000 ampere hour battery bank,
      I will share that that is over a ton of battery, and you would
      be lucky to have them last a decade. That $4000 worth of
      batteries would buy two new 10 horse Hondas, and they would
      probably still be going strong a decade later. For starters,
      when you start talking about 10 horsepower, you are dealing
      with a LOT of electrical power. There is absolutely no
      comparison in terms of energy per dollar or energy per pound.
      Buy the ten horse honda and relax. On the other hand, IF you
      can use the weight as ballast as in a sailboat, the batteries
      are able to do double duty. A previous post mentioned using a
      submersible well pump. Trace makes a gadget that turns 110 into
      220 volts. I have one and will sell it at half price, though in
      my opinion this is the wrong way to go. Stay with DC. Smaller
      boats can be powered by high thrust commercial units just fine,
      and the glen-l idea of putting an electric golf cart motor atop
      an old outboard has a lot going for it. The best application
      IMHO is a boat that sits a lot in the sun and has a few solar
      panels to keep it charged, and possibly a backup battery
      charger. By that I mean a 12 or 24 volt heavy duty automotive
      alternator (mine was converted to 24 volts by an alternator
      shop) powered by a Honda 4 or 5 horse gasoline motor.... or a
      smaller generator. Again, this has to tickle your fancy, or it
      is not worth doing. Even in a smaller application, you will be
      lucky to get by with less than 100 pounds of batteries, and 100
      pounds of gasoline will probably take you 10 times as far.
      Don't want to hog more space - my bottom line is: think
      twice...but maybe do it anyway!
    • brucehallman
      ... That is why I like the idea of a used diesel powered welding machine, which is 40V 250Amps DC. These units sell at auction used for $3,500 and weigh 1,500
      Message 2 of 4 , Apr 30, 2002
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        --- In bolger@y..., Jim Goeckermann <jim@s...> wrote:
        > This is an interesting thread, and I have been thinking ...
        > ... that is over a ton of battery ...
        > ...my opinion this is the wrong way to go.
        > ...Stay with DC.


        That is why I like the idea of a used diesel powered welding machine,
        which is 40V 250Amps DC. These units sell at auction used for $3,500
        and weigh 1,500 lbs. When you want to move, power up, when not,
        power off. The only battery bank would be minimal for cabin uses.

        Maybe an electrical engineer could say if the 40V 250Amp power could
        be fed into a motor somehow. If the motor could be submerged in
        water, then you could avoid a stuffing box, through hull hole, etc..
      • nettech22407
        A possible problem with this is the duty cycle. The welder was designed to put out 40 amps on an intermittent basis. Use of a motor may well exceed the
        Message 3 of 4 , May 1, 2002
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          A possible problem with this is the duty cycle. The welder was
          designed to put out 40 amps on an intermittent basis. Use of a motor
          may well exceed the thermal designs of the electronics because power
          draw from a motor is constant not intermittent.

          You might want to have an engineer look at the internal components
          for the intended purpose.
        • brucehallman
          ... I was concerned about that too, though the Miller Big Blue 251D is rated @40V DC 250A at 100% duty cycle per their spec sheet. These welders can be used
          Message 4 of 4 , May 1, 2002
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            --- In bolger@y..., "nettech22407" <micwal_va@h...> wrote:
            > A possible problem with this is the duty cycle. The welder was
            > designed to put out 40 amps on an intermittent basis.

            I was concerned about that too, though the Miller Big Blue 251D is
            rated @40V DC 250A at 100% duty cycle per their spec sheet. These
            welders can be used in fab shops etc. around the clock under constant
            use.

            Spec sheet PDF file here (takes a while to download):

            http://www.millerwelds.com/pdf/products/ED5-2.pdf

            I agree with you that an electrical engineer needs to design the
            system.
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