Sizing electric motors

Discussion in 'Hybrid' started by ted655, Apr 28, 2008.

  1. ted655
    Joined: May 2003
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    Location: Butte La Rose, LA.

    ted655 Senior Member

    As an example, I include this boat.
    1. What size EMs would one install, (roughly)? 1 for each side wheel.
    2. Would they be DC or AC/ Single-three phase?
    3. Gearboxes or sprocket ratio ed?
    A paddle wheeler seems like a good canadate, allowing for a cleaner/safer engine room.
    .
    If a boat this size was to be converted, & the side wheels were to be used to actually propell it, where does a guy start in trying to learn hybred systems.
    I see this type of propulsion as the now/future.
    I'm just curious about practical types & sizes of the equipment, that will be needed :)
     

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  2. alan white
    Joined: Mar 2007
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    alan white Senior Member

    I think the principal advantage of a hybrid system on such a boat is that the paddles are easily turned whenever it's anchored in a river current. The hybrid boat can be compared with a hybrid car used only at highway speeds, or at least constant cruising speeds.
    In fact, no electric system is really needed by a hybrid car at cruising speeds. The better highway mileage comes from the smaller engine and not the hybrid system. In other words, it would actually be better if the extraneous weight of the electric motors and especially the batteries could be dispensed with once a hybrid car is up to speed.
    then it would really be efficient. But hybrids cars are actually better city cars than highway cruisers.
    Boats, at least paddle-wheelers, are not concerned with accelleration or reclamation of energy upon stopping, and so any electric/diesel (or gas) boat hybrid is going to use electric motors to advantage as river current generators to charge batteries. Lots of batteries in fact, since there should be enough energy storage capacity to run the boat for a day at least.
    Outside of river travel, I see no advantage whatsoever in a hybrid boat.
    restricted to rivers, I see an enormous advantage since no engine is needed to charge the batteries, though there should certainly be an engine (genset)for backup and even (decouplably) shafted to the paddles.
    Ground tackle becomes far more important if one is commonly anchored in a river stream. A mooring or a dock carefully chosen to take advantage of a fast current are other options.

    Alan
     
  3. Guest625101138

    Guest625101138 Previous Member

    I would need to spend a bit of time to do some real performance checks but I think you would get acceptable performance from a couple of these new Mars PMDC on 72V:
    http://www.kellycontroller.com/shop/?mod=product&cat_id=16&product_id=125
    They are continuously rated at 9kW and will peak at 20kW. So get the gearing right and it should go OK.

    I purchased a couple of PMAC Mars motors and 48V controllers from Kelly controllers and they posted them free to Australia. Cost for two motors and controllers was USD1540. I am very pleased with the motor and controller but would opt for the bigger one for the paddlewheeler shown. Not sure if you viewed my first test with the Mars motor:
    http://www.youtube.com/watch?v=2ul6hDx1L50#GU5U2spHI_4
    That is running from two tiny 12V batteries. The unit will crank out 9kW at full power using suitable 48V batteries.

    Once you get above the 72V level you are getting into more serious electrical technology and you need some electrical nouse. There are some nicely engineered systems coming on the market for diesel electric hybrid.

    A feature of the paddlewheeler is the large cabin top that could be used for solar collection. The panels would be expensive as fuel will be if you are permitted to use it for recreation. A lot depends on how far and fast you want to go at any time. You could also use a decent size wind turbine if the place gets wind.

    Rick W.
     
  4. lazeyjack

    lazeyjack Guest

    there seems to be no cheaper solution, than fossil fuel for us,
    You can place a good argument for dc generating at anchor in fast streams, but there is always the huge cost of the battery bank and the regulating gear I think the future will take us round to small auxillary engines and sail, and thats where it all started really when power came into private boating
     
  5. ted655
    Joined: May 2003
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    ted655 Senior Member

    I was thinking of the simplicity of the mechanical & control systems Doing away with all the shafting, connecting & clutching. The ability to not need permanent engine room workers to relay orders from the pilot house. Making for a more responsive boat.
    Going upstream in strong currents would require straight diesel-electric power? Perhaps electric driven prop also?
    BUT, my main interest was a calm water, morning excursion-evening dinner boat for small parties.
    I've been on several such boats where the paddle set solely on bearings, appearing to turn. Diesel screws actually supplied the drive. Something is "lost" in that experience!
     
  6. Guest625101138

    Guest625101138 Previous Member

    What size boat are you thinking about - length, beam and displacement?

    If the paddlewheels are sized for the job they are efficient for operation in calm water. A twin wheeler will also maneuver well.

    If it is just for night time cruising then straight electric and batteries connected to shore power for charging would be a good solution. The motors and batteries would not be any heavier than diesels and associated gear.

    Here are some ideas:
    http://cruisingresources.com/Electric_Propulsion__p2

    I liked the FEYS system but their site no longer works - maybe their system was not very good!

    Rick W.
     
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  7. ted655
    Joined: May 2003
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    ted655 Senior Member

    ========"What size boat are you thinking about - length, beam and displacement?
    "====
    Nothing big. Big "event" paddles seem to be going bankrupt. I think it's the formula of operating, berthing costs/overhead, not overcoming the loss in traffic. That is why the size boat I posted caught my eye. Like Goldy locks bed, it seems just right.
    I think day excursions would also be necessary, in addition to dinner cruises..
    I realize this is a hybrid section more than a diesel-electric, but I'm convinced some form of this technology is what's to come.
    How are the insurance & finance boys treating this type of propulsion?
     
  8. alan white
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    alan white Senior Member

    Yes, I agree that something is lost in such fakery.
    Any electric drive is going to require gear reduction as much as any fueled engine. I believe the complication increases rather than decreases if you drive the wheels electrically. The power plant can be smaller, but I think you'll find that the overall cost will be a lot higher, factoring in batteries, controllers, and so forth.
    Without river current to regenerate, shore power or an onboard genset are required. The propusion could then be silent because you could generate during off-hours.
    A lot of sawmills are going belly up and big electric (three phase) motors would be going for a song. Batteries are expensive, but what isn't?
    How about four husky Clydesdales running a vertical merry-go-round arrangement? A single truck axle with the input going straight up to the horse deck. Individual brakes to turn the boat. No more gearing than the differential itself. You'll make a killing!

    A.
     
  9. ted655
    Joined: May 2003
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    Location: Butte La Rose, LA.

    ted655 Senior Member

    By simplified, I meant ridding the interior of all the myriad of mechanical contraptions it takes to get power from the engine, OVER to each wheel. I'm assuming the electric motors would mount closer to each wheel, with far less chains & belts. Reverse would not be the burden it is on a mechanical drive, etc..
    controls should be simpler. Video cameras & sensors could take the place of a full time engine room attendant. I just suppose a cleaner, simpler plumbed boat. I'll catch hell here maybe, but I envision a straight diesel-electric boat, no batteries, for a boat this size. But, I have an open mind & there is probably a good argument for hybrid.
    This boat is obviously heavy built. A new boat would be lighter, with smaller wheels perhaps. A boat capable of 20 guests for supper & maybe 30 people for a short cruise. A crew of 5. :confused:
    I'm just feeling around, getting to know "stuff" These links are great help, thanks.
     
  10. Guest625101138

    Guest625101138 Previous Member

    The beauty of a true paddlewheeler is the tiny amount of power that is actually required if you only need to do a few knots. Large wheels will give high thrust for little power.

    You are correct about the motors. Modern controllers are fantastic. You can get them for either AC or DC motors and the motor/controller combination give efficiencies 85 to 90%. The Mars motor I have ticks over with 4W and it has a rating of 7kW on 72V. It only weighs 11kg. It can be used for powering or regenerating in either direction. The controller drains 60mA when connected so really only needs a fuse for safety and mechanical connector for disconnecting.

    So you just need to find a nice neat triple stage epicyclic reduction box on a torque arm to mount on each paddle wheel that is continuously rated around 10kW and say 4000rpm input speed. Would not even need a rudder.

    Modern electronics really make things simple. If you are charging from solar panels you do not need to worry about matching voltages. The controller takes care of it. Most units these days have charge maximising strategies built in to automatically hunt out the best operating point for the solar panels.

    Rick W.
     
  11. alan white
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    alan white Senior Member

    Hi Rick,

    Could enough wattage be gotten from a solar array mounted (to articulate?) atop a paddle-wheeler roof top?
    It would be nice if this could be done. What is the yield in watts per area under ideal conditions? Let's assume the area available is 30 sq. meters.
    Let's further assume the panels can articulate on one plane.
    If there are two max 10 kw electric motors (total 27 hp), is that enough power to safely navigate in strong currents? Low speed efficiency (meaning low kw power) is fine in calm water, doing four knots for an evening dinner cruise, but what kind of power would be required to stand up to a 6 kt current? Maybe four times that?
    I'm assuming a boat of about forty-five feet, maybe 12 ft beam.

    Alan
     
  12. Guest625101138

    Guest625101138 Previous Member

    Alan
    A well designed 45ft (say 14m) boat should move along at better than 6kts with that sort of power. I will see what Godzilla comes up with for a boat that will do 8kts and has WL beam of 3m. Lets say it weighs in at 4 tonne fully loaded.

    You can usually find data for expected output from solar panels in a specific location. You could work on about 150W/Sq.m for about 6 hours a day in temperate areas. So your 30Sq.m could be good for 27kWh on a typical day. They would be expensive - something like USD30k. It is certainly best to have them track but I think this is a lot more complex. The value of doing this will depend on the latitude.

    The Sanyo look OK but I have not been able to get any of these so have gone to another brand with similar efficiency:
    http://store.solar-electric.com/sa190wahitso.html
    http://us.sanyo.com/industrial/sola...IP-xxxBA3 Models - Effective 1 April 2007.pdf

    Once you start getting into the numbers you can see why I went for an easily driven slender hull. You need to look closely at the overall design and make the best of what you are using. The batteries provide expensive ballast as well as energy storage. This means you can reduce the WL beam but still have good stability. If the boat is operating in calm water the shape above the waterline is not going to matter much so you can widen above the waterline. Still need to be mindful of windage though.

    Rick W.
     
  13. alan white
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    alan white Senior Member

    Rick,

    Is the displacement realistic at 4 tons? I don't know much about this kind of boat, but would have thought at least twice or three times that.

    Alan
     
  14. Guest625101138

    Guest625101138 Previous Member

    Alan
    I was thinking of lightweight construction in aluminium or composite. It is a river boat. I am happy to use 8 tonne. As long as the target speed is below hull speed the wave drag should not kill it.

    Rick W.
     

  15. Guest625101138

    Guest625101138 Previous Member

    Alan
    I have attached what Godzilla produced for the 8t paddlewheeler with maximum length of 14m and minimum WL beam of 3m optimised for 8kts.

    The attached power curve has an efficiency allowance of 80%. This is possible with good props and I think achievable with decent sized wheels.

    Rick W.
     

    Attached Files:

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