Efficient electric boat

Discussion in 'Boat Design' started by Jeremy Harris, Jun 22, 2009.

  1. Jeremy Harris
    Joined: Jun 2009
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    Location: Salisbury, UK

    Jeremy Harris Senior Member

    Hi,

    After some time away from this forum, working on other projects, I've just popped back in.

    How can I help with the brushless motor problem?

    Jeremy
     
  2. hexadrone
    Joined: Jan 2011
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    Location: ITALY

    hexadrone New Member

    Jeremy waww fantastic thank you for your time :D

    i have one problem with one my brushless

    [​IMG]



    if I touch the area with the red circle in pic ,engine works well, is a behavior very similar to the behavior of the engine that you can see in this movie even if the engines are different:
    http://www.youtube.com/watch?v=Qc820DBIYik

    Is there a solution? what could be wrong?

    Sorry for my bad bad english :(

    thank you for your help.
     
  3. Jeremy Harris
    Joined: Jun 2009
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    Location: Salisbury, UK

    Jeremy Harris Senior Member

    Inside the black sleeve over the three wires from the motor there are soldered joints between the flexible motor leads and the winding wires.

    It is likely that one or more of these joints is faulty - it works when you press on it, but not otherwise.

    To repair the motor you will need to remove the sleeves on the wires (they are heat shrinkable sleeving), re-solder the joint and then fit new sleeving to insulate the joint.

    It is also possible that the more rigid winding wire has broken at this point, perhaps next to the soldered joint. The repair is the same, except you will need to clean off the enamel on the winding wire before making a new soldered joint.

    Hope this helps.

    Jeremy
     
  4. hexadrone
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    hexadrone New Member

    Dear Jeremy thank you is clear but how to reach the interior of:rolleyes: the motor?
     
  5. Jeremy Harris
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    Jeremy Harris Senior Member

    You probably don't need to, as the winding wire to connection lead joint will most probably be outside the motor, under the sleeving.

    You have taken the motor apart as far as is possible without damaging the windings. The stator is glued on to the alloy bearing carrier with epoxy resin and the only way that I have found to take them apart is to heat the whole assembly in an oven to around 120 deg C for around an half an hour, to soften the resin, then try and pull the stator and windings off the central alloy bearing carrier.

    This almost always damages the windings, so the motor then needs re-winding. It also risks damaging the insulation and bonding between the stator silicon steel laminations, which then leads to a much more complex repair.

    Jeremy
     
  6. portacruise
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    Location: USA

    portacruise Senior Member

  7. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    I think an excellent solution, special if one build a New Orleans River boat with the scoops at the back or a Rhine boat , whereby the scoops are on both sides of a boat. Pancake motors can be easy made with more magnets and coils and reducing the revolutions per minute and create larger diameters with higher torque.
    Bert

    P.S. I think it would be ideal for a flat bottom fisher boat, with the motors on both sides in the middle or at the back close to the transom and 2 scoops. By manipulating the speed of one of the motor, one does not need a rudder.
     
    Last edited: Mar 25, 2014
  8. yellow cat
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    Location: magog

    yellow cat Junior Member

    emotors for catamarans

    Also, i think it can be used as a genset with a windmill, hydromill, humanmill ... how fast do you think you can push a 10 tons catamaran in water (with no propeller in water) ? Slow start, but if the footing is right, i think i could do 5 knots ... and i am not Louis Cyr ... we did some testing last summer, interesting results.
     
  9. BertKu
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Yellow cat, Tell us more about it. What waves, how much wind, what other conditions , what kind of method did you apply. etc. A human can create about 300 -400 watt. Not me, I am too old for that, but I would be able to do 240 watt contentiously for one hour. Bert
     
  10. yellow cat
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    yellow cat Junior Member

    Hi Bert,
    This is for a catamaran, so as soon as the wind picks up a little, (5 knots) we can use sails. Props would be used to boost slow winds , no wind at all or to get out of a marina or any other motoring situations.
    Waves and currents are taken into account with the same motoring factors as normally.
    This is for a twin mast cat (look at the hydraplaneur m├ędiatis for example). This is important for the center of gravity.
    Imagine that most of the time, for us especially, the big cat is still. Everyday, well almost..., i train with my wife and friends at the gym for about 1-1 1/2 hr.
    We did some testing and concluded that we are about 3 times stronger sitting vs standing, we dont have to fight our own body w. . For example, in 2 weeks we would train at least 10 times. So about 15 hours ... if i consider only me, i end up lifting weights (sitting on a machine or not) the equivalent of 45 man hours walking pushing the cat. But how to transmit that power or energy to move the cat.
    One needs to either use direct (minimal friction of 10-15%) mecanical energy , or transform that same energy into a medium. Electricity is a likely medium but with a loss of 40% in and 40% out . (we are assessing this loss).
    In either case, i want to control when i input the energy and when i output the energy.
    What is already on a cat anyway that has another use but is heavy somewhat ?
    And how can i spread that energy into an usefull output.
    We came up with a few ideas, but so far the best one is to visualise the bowling alley or the chairlift twins. The idea is to get a continuous flow going down the mast for electricty into batteries ... for convenient clean power. The up flow is with the variable training and other inputs. Also, that electricity can be used very short term / time for minutes in a critical area i.e. marina, ports, etc. , compress that 45 man hrs energy into 15 minutes. Emotor being the best controlable engine.
    I have not spoken about wind , hydro, tidal, waves, photovoltaic, marina power (i'am paying for it ...) , and more. These can contribute to the training ... hours.
    I have an emergency, i have to go out of the office, but feel free to add some ideas.
    thanks
    Mike
     
  11. BertKu
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Thanks Mike,
    You are aware that if you connect 2 pancake low revolution brushless motors electrically to each other, i.e. One pancake motor with some pedals at the steering wheel and the other pancake (should preferable be the same size and make) watertight with a propeller in the water at the transom, that you could paddle your catamaran out of the harbor, while sitting and steering from your cockpit. Try it, you youngsters will have enough energy to make it work. Actual it works with any star three coil brushless motor, but only pancake motors are available at lower revolutions and higher torque for the same power and lower price. This is because there are 150 million electric bicycles in China. The reason why it works, is the EMF/EMK or whatever this is in English. All what you need is two motors and a couple of 3 electrical thick colored wires. If the propeller runs in the wrong direction, all what you do is to swap TWO wires around or put a crossover switch between it. Bert
     
  12. yellow cat
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    Location: magog

    yellow cat Junior Member

    Hi Bert, thanks for the interest to develop.
    So far the best compromise weight to power ratio i found is the Emrax motor.
    This is a promissing technology. Of course there is the Tesla jouvence fountain of energy that can be harvested . I plan to develop a concept that will be easy to repair in a deserted island. Anyone can pretty much do rope work and pulley ajustements.
    I will try to reduce to minimum the necessity for anything that needs motors.
    For example, instead of pumping water, i look at loading some weight onto a bag, hence creating the flux necessary for all types of uses. It may sound simplistic but refinement of design is pushing the design to new heights.
    It goes from simple pumping for heating a floor (we freeze in Canada these days ...) to evaporating water (water maker) . Direct conduction of heat from solar, wood furnace (pleasure fireplace) , showers, dishwashing or engine cooling recuperation . I did experiments for heating systems using floor radiant heating, some told me i was crazy and it would never work to discover not only it works, but it is more comfortable and uses less energy.
    This sounds out of topic for emotoring, but a good part of higher voltage passes through the necessity to cool. ie recup that heat.
    There are more sophisticated systems that can be applied and we are considering them, and at the end of the day, KISS system seems to make sence .
    When my grand father decided to create an exterior furnace for his house, he was looked at as from another planet. Not only he practically eliminated the risk of fire in his house, he was able to burn logs that were less human intensive (whole 4 to 8 ft long logs), he could have heated the whole village with his furnace. this was at the time when foresting was the way to go for creating farm land. Now it would have to be assested as a way to burn waste wood. Besides pleasure fireplaces i am not too keen on burning wood. But i was happy to have my woodstove when we had a power shortage for 3 days at christmas 2013 ... we cooked and heated all we needed. We had to cool things outside in snow ... funny enough, we have a genset and had to lend it to a farmer who needed power for his well pump for his cows. His genset stoped ...
    Now i am sort of awaiting to see nanowood fibers developpement. I had some talks with a company, but they are not ready. I would like to replace the okoume marine plywoods with nanowood fibers plywoods.
    For this topic, we can push the envelope to high grounds with those pancake motors.
    Time to sleep, big day tomorrow.
    Mike
     
  13. BertKu
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Mike, Yes it is also a pancake motor. Good choice.
    Bert
     
  14. TomCat58
    Joined: Dec 2013
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    Location: Washington State

    TomCat58 Junior Member

    Wow a lot of information to work through. Thanks for the ideas and experiences trying different setups. I have a spread sheet I use to calculate speed, amps, distance and battery life.

    This spread sheet is a great way to figure out what different throttle settings actually do. The guy that put this together was dealing with a Hobbie cat and a small battery but no worries he provided a spread sheet were a person can change the values to match his own motor battery etc.

    I will be testing my present setup on this spread sheet and will share the out come. I hope others will do the same and we can all see clearly what works better and what does not.

    It will be a bit time consuming but very easy to see the pro and cons of any components changed. Here is his website and there is a "link" to download a functioning spread sheet and all you have to do is change the information to match your own. I made a water proof clear case and it has 2 amp meters inside. one amp gauge shows how many amps the solar panels are producing and the other amp meter shows how many amps the trolling motor is using.

    I will post a picture when I get enough post to allow me to.

    for spread sheet copy and paste below:

    http://tufox.com/hobie/TrollingPerformance.html


    TomCat
     
    1 person likes this.

  15. yellow cat
    Joined: Mar 2009
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    yellow cat Junior Member

    Hi everybody
    I have been studying more on the costs of materieals vs finishes lately. The idea being to use a material that can be apparent inside and outside the boat. So when it is done, it is done. So far we have 2 materials that retained our attention , Polycarbonate and Polyethylene (like the fluted greenhouse flexible panels) . This seems out of topic for electrical motorisation, but Polycarbonate has good elect. properties. If we want to protect our propulsion e-system, this is something to think about.

    My conceptual reflection on electrical motors was originally based on 2 major factors.
    1 - it is good for snap power at in and out of marinas, and no need to heat up the engine(s), pod possibility, noise, etc
    2 - i can manufacture electricity , not gas or diesel or propane or ... perhaps ethanol ! ... in various ways, wind turbines, solar PV panels, human bicycle, hydro regen, hence vapor , reversed peltier, and few more.

    This said, i find that the costs of batteries and engins are ridiculous . Electricity still needs to be paid for . Not considering the potential danger of electrocution , (could be more or not an issue than gas, propane ... ) would be an error.

    This is why i now want to limit the voltage (less efficient) and try to use mechanical energy . This is where the programme of the boat is crucial. Generally, this will be my case, the boat is mostly a cheap (can be for BYS project) way to have a house. That house is mostly idle in a nice spot, conveniently located for my activities. That is surfkiting, catamaran, windsurf.

    It is fair to say that the vast majority of boats dont move most of the time and when they do, it is not the majority of the time. Mostly for in and out of marinas, moorings, anchorage, beaching. E-motor is hence the best way to go , or is it ? The more i look at it, the more i see an emotor as a genset for doing other things as well.

    We are evaluating how the human factor can play a larger role in propulsion of a boat.

    How fast can a normal man push a 60 ft catamaran . With good footing and no prop and no wind to fight against, 5 to 6 knots seems possible. We have concluded our tests and on a short term basis it seems to make sence. For example, if one lifts weights up a mast (60 ft mast) for an hour, not only will he show 2 -3 times more power than standing up and pushing , all that load can be used in a shorter period to rotate a prop. So for 15 minutes , one has the power of 12 people pusing at about 90 pounds each.
    A combination of multiple bungies, and dead loads (chain, anchor, water, etc) can do the trick. If not for propulsion, for e-production it can. Can we use other ways to lift those, yes. But daily exercise is good for you. Tides become more interesting ...

    food for thought

    Mike
     
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