Electric motors - Do they need to be so expensive

Discussion in 'Propulsion' started by Kaptin-Jer, Mar 28, 2008.

  1. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    Yes politics means life of the city.
    In our water city, acting for technical choices is a political act.
    When you say, no way, i do not use petrol, your technical choice is political act.
    You like it or not, this is just a fact.

    First by the "auto-profethising" effect you stimulate your wills, innovations and changes
    Second when an EV boat works, oil saved can be used for more valuable use such as composites, aramide and carbon
    This changes economy.

    Doing an electric boat is political


    Think global - Act local. Jacques ELLUL
    Last edited: Mar 9, 2009
  2. ASM
    Joined: Sep 2005
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    Location: The Netherlands

    ASM Senior Member

    O dear..


    Good to see you took the faux trimaran a little further, its nice to see my idea gets used for the purpose I would have liked to use it (if I had time and money). Are you building it at the moment ?

    As for the electric vs. petrol....... I see mydauphin comes from the US and in particular Florida.... STOP burning all our fuel and buy a sophiticated boat, one that is designed for normal fuel consumption and not one that pushes water with as much power as possible, its the old phrase again, no substitute for cubic inches.... that is why US brand cars are 10 years behind the Europeans... and see where it gets you when there is a crisis.

    Do not compare apples with pears, a fast planing petrol boat can not be converted into an electric version, true. Once you use a dedicated hull design, electric is an option and wil become THE option in the near future.

    And you want to go sea worthy at 20 knots ? Look at this one:


    2 x 60 Hp petrol outboards, so that's ~43 kW, BUT efficiency of electric engines is much higher, so my guess would be 20 kW motors (?).

  3. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member


    Not practical for most uses.

    I will prove it. I will pick a cheap little boat. Design a boat that matchs its performance- "that can be built". I will give you a million dollars...So will a lot of people.

    The boat http://www.carolinaskiff.com/listman/listings/l0075.html

    Check out weight, draft, size, speed, range, reliability and finally cost.
    I will bet your boat will be far heavier, far slower, far shorter range and a general pain to use. And on top of that your boat will be 3 times more expensive to build and require more resource to build it.

    Finally, if we are going to the apocalypse in the world economy, and headed to a Waterworld/Madmax scenario....Do you really want to outrun the pirates in a electric boat .... Your are going to be troiling for your life....

    Lastly, all in good humor, I hope you don't take personal offense. My only goal is help people understand the practical truth about boating. So people don't get hurt by thinking their electric boat is going to travel to the middle of the Gulf and they all end up in the bottom of the sea.
  4. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    wowwwww !

    Electric pirates ?
    What a thrill !
    I love this ! Well found ! Kids will love electric pirates histories !
    Except that pirates use unsinkable multihulls,
    so happily, only fire can send then to the bottom of the sea.
    I bet pirates win !

    Chaos is not coming from electric boats but clues point in direction of big glass buildings

    And also i think pirate could be a mistake

    They are not pirates, but corsairs of her majesty !
    Their Queen is the earth and human is King !

    I love corsairs, nice good French boats to learn safely sailing to girls during summer.

    I will keep you informed of the cost and the performance of my project when finished. We will see what will be the numbers till then, it is just speculation :)

    Tank's participating, your ideas are welcome, no problemo with me !
    Fuel hybrid boats have applications for sure, but should be a second choice for urgent cases, common transport should avoid fuel and prefer this to speed.
    Motor cat you show is nice, but When i read 1 liter per nautic mille ! What an appetite, 100 nM = 100 litres ! Huge result !
    As by the end of the month i have to go to la grand motte, from southampton i need...1200 liters, my god i have to get new tanks !
    We could do better i think...but not that fast, i agree. But this could change in a very few years
    Of course if you take the time you loose refiling and time lost working to get the extra money, i'm sure a good donkey could ride faster :)
    Total over all cost is what you put inside !
  5. Guest625101138

    Guest625101138 Previous Member

    You are still around.

    The faux tri played on my mind so much that I ended up seeing what would be possible. It is far superior to a monohull and the monohull has marginal initial stability. It also offers much more sensible accommodation. It has been a complete change of tack and I have not gone beyond the power calculations and some basic layout. My weight target has not been confirmed by the NA yet.

    I am in somewhat of a go-slow mode conserving cash to make sure I do not have to liquidate assets at reduced prices. I can ride it out for two or three years even without work if I do not spend much. At the moment I am still employed through the good graces of the US tax payers.

    I have been heavily committed to pedal boats over the last twelve months and want to do this till the end of the year. I have all the materials for a very light weight CF hull and already have new CF frame and CF outriggers. There is a fellow here who wants to better the world record set on my V11 design in Montana last year. He will use my boat:

    I also want to build and test a wind turbine and play with some decent solar panels before I start the hull for the Solar-Wind boat.

    There are some nice developments with lithium batteries that I am also following. I have actually seen the linked batteries in the flesh and would love to have a dozen of the cells to play with:
    Twelve would give me enough for serious trials and ultimately a full set of 48. Total weight just 80Kg so about 1/3rd the weight of VRLA for same energy and far higher power capability as well as cycle life.

    My next step for the faux tri will be a decent model maybe later this year to look at the proportions and get a feel for any odd characteristics. I expect the model will be around 1/7th scale.

    Rick W
  6. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair


    Agree again !
    Seems realistic to me

    Lets make our boat, any scale, this will give the answers !
  7. sigurd
    Joined: Jun 2004
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    Location: norway

    sigurd Pompuous Pangolin

    What is it about these lithium batteries, Rick? 18650 are lighter. Do they last? Are they cheap? Do you have a data sheet?
  8. Guest625101138

    Guest625101138 Previous Member

    The LEV50 batteries are rated at 50A and 3.7V. I expect you could easily pull 250A from them but I do not have the power data. They are being used in the Mitsubishi MiEV and are made by Lithium Energy Japan, a joint venture with Yuasa.

    The main features over the 18650 cells is that they have much higher energy capacity and use bolted connections. You would only need 12 of these cells to make a battery capable of 10kW and I expect it would delivery that power efficiently. The weight would only be 20kg. The batteries could be joined with copper bus bar. THis is a far better solution than stacks of tiny cells.

    You would expect they will be reliable as they are being produced for mass market use. Although I cannot verify this. As far as I know they are not commercially available yet. It could be Yuasa cannot produce enough to meet the demand for Mitsubishi. Mitsubishi are pushing this vehicle hard and I can see a lot of people considering it:
    http://www.promo.com.au/mitsubishi/MIZ1043/media/Mitsubishi i MiEV, the future is here now.pdf
    The advantage of being able to plug into the home socket is a big feature for many like me.

    The vehicle is not what I consider pretty but it seems to be the first realistic full electric.

    Toyota and Honda are pushing hybrid hard but there is a place for small all electric like the MiEV. The new Honda insight is a sleek looking car and I think will get a lot of attention:

    I will look closely at the Prius and Honda models for my next car but the idea of never having to visit a petrol station again is appealing. There are issues though because puting my 7.2m long pedal boat on the roof of a 3.5m long MiEV might get some attention. My wife would never let me put the boat on top of her car and I do not like the idea of keeping another car just to carry a boat now and then. I also found out that Prius do not sell a tow pack here and I expect the MiEV to be the same. I did not ask Honda.

    Rick W
  9. sigurd
    Joined: Jun 2004
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    sigurd Pompuous Pangolin

  10. Guest625101138

    Guest625101138 Previous Member

    Yes I know this. Lithium is the most reactive metal and hence the reason for such high power density.

    I regularly visit the site you linked to but I am not certain about reliability of the batteries being produced so far. There are some bad reports.

    Yuasa is highly respected and I expect that they will gear up to produce top quality. However if it is not available or simple way more expensive then I will try something else.

    With my initial design I had settled on VRLA but the lithium technology is advancing so quickly that it needs careful monitoring.

    I would like to buy something like a 40V 10Ah, 10C lithium battery for serious testing of my Mars motor but they are a bit too expensive for just a trial. Right now I play with two 12V 10Ah VRLA batteries but they power limit around 200W on the 18V controller low voltage limit so not much use for serious testing of my 4.5kW motor. Did you ever see the test video of my Mars motor:
    It is reasonable when you consider I am only getting 200W from the batteries. I could do some impressive speeds on this tubular cat with 4.5kW.

    Rick W
  11. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    Batteries and protection

    Any Batteries and open and non dual shielded cable or equipement should be in a strong close box only
    To be IP68 protected from water you need to be abble to protect your battery from immertion in water !
    This is not impossible but in real condition, in a moving boat, in gale or just moved by wave pressure and destruction force will be very high !

    BOX fitted with
    a permanent air exhaust valve or a fuse valve zone with less resistance that will break first in a safe controlled direction, can be done by a spring loaded valve.
    The aim is to let out correctly, where we want, regular and accidental gas.

    Of course also, never mix sparks generators, such as mechanical switches and batteries... in the same box ! Especially for lead batteries producing hydrogen in large quantity that would be much greater if used to run the fuel generator that can be a very small size hydrogen motor starting when there is enough hydrogen, giving a few amps more :) Lead battery could become more efficient this way ?

    Even the best quality battery can fail, from then...do we have the choice
    Only fire can sink a light boat. Amp and Amp/h is potential fire
    an automatic fire extinguisher covering heated zones is a compulsory choice i guess ?

    doing only this i bet risk get very low with any battery

    Rigid luggages are great boxes that cost few €/$/£; second hand or even new ...
    They can be strongly closed, secured with aramide fibers links, tight and epoxy glued. Mini 6.5 racer do that way for years for everything to secure or link aboard. Inexpensive solution

    But this far from propellers...


    Last edited: Mar 9, 2009
  12. sigurd
    Joined: Jun 2004
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    Location: norway

    sigurd Pompuous Pangolin

    With the bell, the batteries would get wet when boat is upturned?
  13. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    upturned yes

    That is right, you lose batteries
    But you also have lost your boat

    ... my study case is a multihull...

    Upturned you do not need motor :), just radios

    Keep in a bag a survival 12v kit
    IP68 diving small lipo 12 V battery,
    a IP68 solar panel,

    just to feed IP68 VHF and GPS or diving computer
    you may drink piss before loosing your GPS and radio

    Do not to forget ...enough good drinking water
    that is all u need

    So to stay on the question of price
    The conclusion seems to be :

    IP68 propulsion and IP68 energy storage under the form of batteries.
    offer reduced cost and hight reliability

    Installation is less expensive and simpler for a multihull

    Love multihulls...
  14. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    End of transmission, i go sailing for a while
    Thank's !

    François BOUQUIN

  15. apex1

    apex1 Guest

    Gaawd, we´re happy................... circumnavigate!



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