Electric propulsion with recharging for long range

Discussion in 'Electric Propulsion' started by Gasdok, Aug 12, 2020.

  1. Gasdok
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    Gasdok Junior Member

    Has anyone done any work for electrical propusion with a recharging system for long range? Apart from Elon Musk.
     
  2. Rumars
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    Rumars Senior Member

  3. gonzo
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    gonzo Senior Member

    Almost every electrical propulsion system is designed for recharging. You would have to define long range to be able to answer your question.
     
  4. Gasdok
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    Gasdok Junior Member

    They have done some ferry boats in scandanavia w on shore recharging.
    Thinking a diesel generator for reccharging like an old u boat?
     
  5. gonzo
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    gonzo Senior Member

    If you are going to recharge batteries with a generator, it is cheaper and simpler to use the engine to propel the boat. Wind charging makes no sense to me either. Might as well sail. Solar charging is possible, but unpredictable and doesn't work at night. There are reasons for electric propulsion in a long range application. However, saving money is not one of them. Also, the boat has to be ultra-light, so no frills allowed.
     
  6. Rumars
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    Rumars Senior Member

    Gasdok, can you be more clear about what you want to know? The chargers themself are no problem, we can charge MW of batteries as long as we got the power from somewhere. Charge time is limited by the battery acceptance rate, wich varies with chemistry and exact build method.
    If you are asking if anyone has buildt a chain of recharghing stations, no they have not. There is power at every dock, so small batteries don't need special stations. Bigger batteries can use the bigger outlets available at the superyacht docks or just stay plugged in longer.
     
  7. Gasdok
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    Gasdok Junior Member

    Thinking in terms of a prius like hybrid system that would allow much running to be done off electric motors.
    In a fishing boat for example run at speed 1 hour, troll 6 hrs,run back at speed.
     
  8. gonzo
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    gonzo Senior Member

    The operating conditions are totally different. Hybrid cars get more fuel economy by regenerating braking energy and using electric power for hard acceleration. Boats are the equivalent of your Prius running continuously uphill with a loaded trailer behing.
     
  9. DCockey
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    DCockey Senior Member

    Fundamentally different than a Prius but a sports fishing boat which uses electric for trolling and gas/Diesel for high speed may be reasonable, depending on the characteristics of the boat, speed requirements and other electrical requirements. Again, this would be different than how hybrid road vehicles work.
     
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  10. gonzo
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    gonzo Senior Member

    Electric trolling motors are a common application.
     

  11. philSweet
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    philSweet Senior Member

    The problem is that energy storage is much, much more expensive with electric. It is also a lot heavier and bulkier. The typical sport fish charter buys fuel by the ton daily. That's why it doesn't work. Lead acid batteries weight about 100 pounds to store one pound equivalent of diesel fuel. Even if you can recharge them for free, the cost of replacing the batteries will equal the cost of all the diesel represented by the electricity stored in the batteries during the batteries' lifetime.

    Lithium Ion cells are about 10 times lighter, but require a great deal of attention and management. By the time you look at the complete battery system with all the electronics, the system is no where near 10 time denser.

    System integration is moving along slowly, with electric propulsion options slowly being extended to smaller and smaller vessels.

    Yanmar recently teamed up with a major hybrid systems integrator (Transfluid) and I believe you can now buy a 400 hp Yanmar diesel with all the hybrid goodies right out the box. If true, that cuts the minimum size of OTS hybrids in half.

    Yanmar/Transfluid diesel hybrid drive system for marine applications https://www.greencarcongress.com/2018/04/20180410-yanmar.html

    Otherwise, It is still largely a DIY affair, with integrating the diesel and electric via the tranny a major constraint. Appropriate pti/pto trannies with integrated clutch controls just aren't available in small sizes. The same is true with cars. There have been dozens of tranny patents and prototypes by all the major automotive that allow full electric machine integration into the drivetrain via a tranny pti/pto, but none are in production as far as I know.

    Well wadaya know, Volvo has one now - In production on the XC 90 if I understand correctly - of course it costs more than my house. And interestingly, it is also a 400 hp unit.
     
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