Magnum 53 Hybrid

Discussion in 'Boat Design' started by John Kane, Jun 8, 2013.

  1. Nate57
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    Nate57 Junior Member

    I apologize if I'm mixing politics in here but I just have to laugh when someone burning 2 gals/mile thinks he's doing something good for the planet! You have your figures all mixed up my friend. Also your idea of leaving your electric driven propellers turning when under diesel power is just a very inefficient way to charge off the mains. Please consider buying a true hybrid, a motor-sailor. Silent trolling all day!
  2. daiquiri
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    daiquiri Engineering and Design

    Now that is a sound advice. :)
  3. John Kane
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    John Kane Junior Member

    I had no intension of running the diesel main engines at low speeds in fact this is what I am trying to avoid but when fishing it is inevitable that you will spend long periods of time at trolling speed therefore relatively low rpm which is why I would like to run on electric for a large part of the fishing day. This will reduce the hours running at low rpm and reduce the overall engine hours which is a considerable saving on the kind of diesels I will get a figure on a 1000h service on twin MAN V10 820hp(or if anybody could help with that let me know)

    If you guys had gone through my last post properly you would have seen that I have put in a high efficiency dc to dc generator 6kw to take care of the house loads as well as help charge the main bank. You are all missing One very important part that no amount of talking can solve and that is the sound of silence. This applies to traveling on inland water ways or bays,inlets or marinas as well has spending a quiet night at anchor at a deserted island in the Bahamas.
    Not to mention on a global scale their are an increasing number of areas world wide which do not allow diesel powered vessels.
  4. John Kane
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    John Kane Junior Member

    Nate the electric motors are coupled to the drive shaft of the diesel engines therefore when the diesels are running the shaft is turning and power is being fed back to the battery bank(the electric motors are acting as powerfull alternators) this function can be turned on and off as desired to couple or un couple the electric drives.

    The scale is not important in referance to your 2gallons per mile comment
  5. philSweet
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    philSweet Senior Member

    John, you are certainly taking a brow beating over this for no good reason that I can see.

    Just a couple of points. I would regard the solar collection and controller as a completely separate entity from the hybrid drive and lithium batteries. Each has to stand on its own merits and there isn't any sympathetic benefit from considering them as a pair, as far as I can see. In real life, I think you will find that the bulk of the solar collected can be shunted to the house without ever seeing a battery. Similarly, I'd bet less than 5% of the lithium cells requirement gets fulfilled with solar (this is a good thing actually, although it may not sound like it at first). Thus there is precious little reason to marry them together, and some fairly good reasons not to. I'd think I'd want the lithium BMS fed by ac. If the diesel alternators are 24 volt, use a decent inverter to get the ac for charging enroute. I'd use an ac genset. The solar would go direct to conventional wet lead house batteries (not SLA, VRLA, AGM, or gel) and could help with the start batteries via ACRs. The point of all this is that you really need to consider the lithium BMS as the heart of the entire system and build everything else to play nice with the BMS. The fewer things feeding the BMS, and the more reliable they are, the better.

    As others have pointed out, Any efficiency concerns regarding the charging systems get swamped in big picture by the operation of the mains. The only efficiency concerns begin at the lithium batteries and run from there. That's what impacts costs.

    There are several benefits which haven't been mentioned-

    The comfort of arriving at the dock with a stone cold engine room is probably able to save you 5000 btu in installed ac.

    I'm sure you can dig up a cost to idle a pair of those engines for an hour.

    I'd size the genset bigger. Enough to run every charger simultaneously as well as all major house load appliances. So it runs when you need it for something, and handles the charging at the same time. 20 kw sounds reasonable offhand. The 6kW unit may very well end up running six hours a day. The 20 would need less than 2 hours. Basically, it allows you to hammer away at all the power hungry tasks for 2 hours and then shut it down with all the house cool and the holding plates frozen and the laundry done and the watertanks refilled and the boat washed down and the cooking done and the batteries fully charged. Then you can carry on with batteries for another peaceful 22 hours.

    Not sure if the change to an ac bus affects other aspects of your design, but I wouldn't want any possibility of a direct solar to lithium circuit to exist. Such as the solar controller shorting and sending the panel open circuit voltage to the batteries. A wet lead battery will just boil off a few gallons of water. No big deal if you notice the sudden change during the first month. You don't get a month with lithium. You might not get an hour.
  6. WestVanHan
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    WestVanHan Not a Senior Member

    Rehashing what Jeremy has posted,another way to look at it:
    burrning 5 gph..let's be generous and say the engines produce 20 hp per gallon per therefore it takes about 100 hp to move the boat at 5 knots.

    Your battery pack will be wiped out very quickly,get your watch out and see.
    I hinted in the hybrid thread- 20 hour discharge rating.

    I do appreciate the silent trolling...again,to reiterate-how about a genset running motors hooked onto the shafts. Who cares if theya re not
  7. FMS
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    FMS Senior Member

    I also appreciate silent trolling as an advantage that a few boaters would pay a high price for. I've also become more sensitive to exhaust. When I was younger gasoline and even diesel exhaust didn't bother me. Now I'm more aware of any exhaust that blows back when idling, docking, anchoring, etc.

    I'm curious to learn more about the places you might cruise that don't allow diesel powered vessels.
  8. Jeremy Harris
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    Jeremy Harris Senior Member

    By all means choose to disbelieve what you're reading here, but bear in mind that this topic comes up time and time again, always with overly optimistic estimates of the true effectiveness of the solution.

    Those of us who've worked with electric drives, solar power systems and lithium battery energy storage tend to have learned the hard way about their shortcomings and costs. Not to say things won't get better as technology improves, but you do need to bear in mind that the laws of physics are not likely to change any time soon, and we haven't yet found a way around them.
  9. John Kane
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    John Kane Junior Member

    To FMS I know this is not a big factor currently however I can see this being more common further down the line. "powerboat operation on freshwater lakes often is restricted. To prevent pollution and overcrowding, authorities in some regions ban operation of gasoline- or diesel-powered pleasure boats during the summer months, or they no longer issue new registrations for such boats" this is just one article I found on a web site referring to Europe. My wife also gets very nauseous when around diesel fumes.
  10. John Kane
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    John Kane Junior Member

    Ok here sure some numbers from an engineer not related to this project.

    These numbers are very specific to this boat and will vary widely with other boats.

    By design sports fish boats have large engines for the length. This means most are fitted with trolling valves to allow clutch slip to slow them below hull speed. This is one of the reasons they are relatively inefficient at slow speeds so we are using a 1gallon per mile figure at 5 knots and 2 gallons per mile at 30 knots.

    At cruise speed we are using a figure of around 800hp is being used and the electric motors when coupled to the prop shafts are able to regenerate the 30kw battery bank in 1h.

    In order to charge the batteries in 1h the engines will need to produce 840hp instead of 800
    This represents a 5% increase.

    This will mean a 2.1 gallons per mile figure
    After 1h at 30mph this represents a 3 gallon increase to fill 30kw
    30 kw under electric power at 5 knots will give 2h running and 10 miles
    10 miles for 3 gallons
    That represents 3.3 miles per gallon
    Diesels 1 mile per gallon

    In my original post I used 10h of electric at an average of let's say 5 knots so 50 miles
    50 miles at 3.3 miles per gallon is 15 gallons
    50 miles at 1. Mile. Per gallon is 50 gallons

    35 gallon saving at let's say $4 a gallon is $140 for the weekend in fuel not $1000 as I posted.

    I will for this purpose say we are doing this once a week so 50 times in a year or $7,000 in fuel savings.

    Now lets talk engine hours. For these engines the 1000h service will be around $20,000
    That's $20 per hour 10hour electric for 50 weeks that's a $10,000 saving

    Solar $10kw a day 365 days is 3,650kw or $1,825 a year using a figure of .50c to produce 1kw from a generator.

    Conclusion is annually $7,000 in fuel
    $10,000 in maintenance
    $1,825 in solar
    Total $18,825 per year

    System cost is $70,000

    That is a 4 year payback not to mention all the other benefits and redundancies

    25% return on your investment try and get that from a bank
  11. tomas
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    tomas Senior Member

    There are two independent catamaran projects built to completion that I read about recently and both had twin electric motors installed for propulsion. They since have both been switched over to direct diesel propulsion because the actual performance of the electric motors fell well below what had been anticipated. One was in the San Francisco bay area and the owner was selling his electric motor pair on Craigslist.

    It seems that the actual power required is always beyond what we would like to believe.
    (Some new variation of Murphy's law)
  12. John Kane
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    John Kane Junior Member

    I am not using the electric motors as my primary drive but as a convenient redundancy when the time is rite
  13. tomas
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    tomas Senior Member

    Hi John

    That was a general comment simulated by Jeremy's post and was not directed at you. Any successful hybrid project helps all of us in the long run. Please continue.
  14. philSweet
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    philSweet Senior Member

    Not surprising. But compared most other hybrid dreams, this one is actually doable. John may not be an engineer now, but he will be close by the time he pulls this off. The majority of people seeking to save money would probably go about it differently. But if we take the info presented as givens, mostly the engines, then I think the concept is valid and doable. Keeping to the 70K budget will be the biggest challenge. John will have to keep things very straight forward to do that. Keep it simple. If it isn't there, it can't break. In my experience redundancies usually translate to headaches. I'd rather buy a Sea Tow membership than fork out for a redundant system. It's enough of a struggle just to fit one of everything on the boat.

    (Once upon a time, I decided to bring a tired, neglected, highly redundant com system back to life. It took about three years. There always seemed to be something that was "actually broken" that was more important. I cycled damn near 400 electronics drawers though the lab, then had them taken apart AFTER they passed checkout and fixed everything else that was wrong with them. Redundancy is just a recipe for neglect. The powers that be just want it to last until they are elsewhere and promoted. Degraded systems get scored by the man in charge to suit his fancy or his proclivity for denial. Most days, fixing that system was like trying to squeeze blood from a turnip. Sorry about the rant.)

  15. viking north
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    viking north VINLAND

    I'm going to stick my neck out here and make a statement --I think all this DC/internal combustion hybrid is nothing but a bunch of smoking mirrors. I'll go one even further, when everything is factored in and I mean everything including the manufacturing, servicing, and disposial of all the systems parts: all this DC /solar/wind generation/internal combustion hybrid main drive systems combinations saves nothing in fuel, reduction in pollution or greenhouse gas generation. I go one further, in the long run over the life of these fancy/dancy systems we are actually wasting more energy and generating more pollution than if a highly efficient internal combustion engine were used alone. With todays technology, a basic well designed sail boat/motorsailer is as good as it gets.

    A yacht is not defined by the vessel but by the care and love of her owner---
    Last edited: Jun 12, 2013
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