Seeking speed with a 3hp electric outboard ...

Discussion in 'Boat Design' started by istock1, May 15, 2009.

  1. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    I would like a lot of things. But really I need a bilge pump that pumps. A starter that starts. LED are great to keep power requirements down. Inverters that are efficient. Generators that are silent. Batteries are pretty well developed unless you want an electric powered boat. But there problem is that HP or KW needed are very large. Anyone that thinks a 20hp electric motor is going to travel far is unrealistic and has no clue about the Sea. Also electric efficiency require large voltages of at least 60 if not 144 volts. These can be very dangerous when not if water gets in.
     
  2. BertKu
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    BertKu Senior Member

    I am not living in the States, thus I would not know what a blue top battery is. But I would not advise you to put 2 x 1000 Ampere batteries parralel, In serial, yes, but not parrallel. The differential current is enormous, as you cannot guarantee that both batteries are 100% equal. Secondly a capacitor like EEstor can handle 3000 Ampere with ease. Because of the porous ceramic material used the weight is a tremendous advantage. The offer is there. Shall we make a 500.000 FARAD 24 Volt capacitor?. Please just do your calculations and see how much energy it will give you on your boat.
    P = Voltage x current. Time in seconds = 0.693 x Capacitance in Farad x resistance of user item like motor example 24 Volt motor 30 Ampere = 0.8 Ohm ...... Time = 0.693 x 500.000 x 0.8 = 77 hours, but then 1/2 the time, the motor has no more 100% power. Make it thus 35 hours of usable pleasure.
    35 horsepowerhours is good enough for me. For you? Bert
     
  3. BertKu
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    BertKu Senior Member

    Please do understand, you can put 30 EEstor capacitors parrallel or in serial without any problem. If we make a 500.000 FARAD capacitor 24 Volt and we make 30 of them it would give you 1000 horsepowerhours. The boat would not even know it that it is carrying 30 capacitors. You would need a magnifying glass to find the capacitors. That is what people should understand what EEstor has developed. Watch the automotive industry they will kill this project. Watch my word. But if we make an open platform capacitor, they have lost. They cannot kill it, it is open platform. Please let me now prepare myself for my overseas trip. Bert
     
  4. mydauphin
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    mydauphin Senior Member

    Blue top http://www.1st-optima-batteries.com/index.html#marinestarterspecs

    I have two in Parralel in my truck. 35hp is about the size of my bow thruster powerplant, no kidding. I have a diesel driving a hydraulic pump to power boat thruster. The reason I have hydraulic bow thruster is because electric ones overheat if used for more than a few seconds...
     
  5. BertKu
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    BertKu Senior Member

    Lets hope that you will never get one cell faulty. You will see what happens to the other battery. Maybe you have long leads which absorb the differential. Most likely both batteries were new and installed at the same time. But a battery manufacturer will not advise to put batteries parralel, unless both are exactly the same. In age and in quality and in performance. All my cars are diesel, my colt, my x-trail, my Nissan . I love diesel, but it smells and a capacitor is clean, no smell, can be put parrallel or in serial, long life, high currents etc. Sorry to hear that electric bow thrusters overheat. Also Volvo from Sweden?

    Bert
     
  6. mydauphin
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    mydauphin Senior Member

    I use biodiesel when I can - trucks smells like french fries or fish sometimes
    Batterys usually go bad together. But they lose amps and I use them on something else. I mention about electric bow thruster because everyone thinks they can use any electric motor and get long lasting performance in a boat. Not true, it requires expensive motors, controllers, etc...
     
  7. BertKu
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    BertKu Senior Member

    Two batteries parrallel

    One could avoid that both batteries goes bad by having in line of each battery a shotkey diode, 200 Ampere or so. The voltage drop is acceptable, Should one battery go, it will not pull the other one with it.
    Bert
     
  8. istock1
    Joined: May 2009
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    istock1 New Member

    So man years later ...

    After many years of having the electric outboard colecture dust in the basement I finally started using it last year. In a 16' jon boat with four 12v rv batteries I can get about 7 knots for 45 mins or so. The stern sits really low in the water though with all that weight, and there is a jumbled mess of water dragging behind the boat. I imaging it is an efficiency nightmare with a low hanging square backed transom.

    I have seen "flotation pods" online that look like they would raise the transom as well as taper the back a little to allow a a cleaner exit ... do you think this would be worth doing? Thanks for any advice.
     
  9. BertKu
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    BertKu Senior Member

    I placed on my transom some 180 liter extensions, which compensate for additional weight I have added with batteries and solar panels. However if I were you, I would consider some lithium batteries and buy every month a 16 Amphour High Voltage type. (I am planning that also) It will cost you some money, but making some transom extensions is also not too cheap. Bert
     
  10. Irie
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    Irie Junior Member

    Losing some of that battery weight would probably help some. I use 48v modules from a Chevy volt with my electric surface drive. 42lbs per battery (48v 45ah). Have you tried moving the batteries around?
     
  11. portacruise
    Joined: Jun 2009
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    portacruise Senior Member

    Hydrofoils may be the way to go for more speed and efficiency with your existing hull.

    PC
     
  12. kerosene
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    kerosene Senior Member

    Hydrofoils? At 7 knots, trolling motor and lead acid batteries? I am confused that does not seem like an obvious solution.
     
  13. sailhand
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    sailhand Junior Member

  14. portacruise
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    portacruise Senior Member

    SH,

    Really like your cat, top notch!

    Here's a crude home made version of what I was thinking:

    https://www.youtube.com/watch?v=SFZwUxEbxW0

    Yes, I know it is 5HP, but there are smaller human powered versions that start flying at under 1 HP!

    PS: I really don't like hydrofoils for myself, they require clear water and greater draft which isn't the case for something like what you have!

    PC
     

  15. istock1
    Joined: May 2009
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    istock1 New Member

    I wish

    Those ideas all look really neat, for now i am stuck with a 200 lb boat, 300 pounds of motor and batteries, and 500 pounds of people and gear. Any little efficiency boost would be great, either in speed or battery life.
     
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