Charging Up to Hybrid

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  • 22 Nov 2019 00:26
    Reply # 8133850 on 8133077

    Please keep us posted on the results, and your satisfaction on this.   There are a lot of folks who are interested in electric propulsion.   I work on diesels all the time, and consider them extremely reliable dependable long life engines.   Keep clean fuel in them and minimal maintenance, and they never let you down.    I do have huge issues with marine installations with raw water, or heat exchanger systems, especially the former.   I just did a major rebuild on an Isuzu 4BG with slightly over 22000 original hours on it.... yes that is twenty two thousand!   It had regular maintenance, and I had an injector pump rebuilt on it a few years back.  It was still running strong, but I didn't like what the oil pressure was doing.  Internally it was actually in quite good shape, but the relief spring in the oil pump was acting up.   An expensive engine to work on, but considering the hours, the owner couldn't complain...

    Just a few numbers.....  one horsepower is approximately equal to .75 KW   or 750 watts.   2000 watts = a theoretical 2.66 horsepower, but one needs to factor in electric motor efficiency, which maxes out at 85%, and ranges from 70% to 85% in the real world.   Assuming 80% efficiency, your real world  horsepower will come in about 2.13 at the shaft.    That makes it extremely important to have an efficient prop.   Prop diameter and optimal pitch for the speed you are cruising at are critical.   

         To achieve your 10 horsepower should require 9375 watts factoring in the efficiency of 0%    At 48 volts, that is 195 amps, which is about what an automotive starter draws.  You will need a LOT of batteries to get much performance out of this system.   Do not depend on running from the generator.   Run from the batteries and supplement the charging system from the generator.  

          My pencil says it's impractical.   If I sound like a skeptic....  It's because I am.    But I'm a skeptic who would love to be proven wrong.   I look forward to owning an electric vehicle or boat someday, but I've learned the hard way not to be an early adopter.   I'm thankful that there are people who are, otherwise technology would not move forward.  I  have an intense dislike for fast talking salesmen selling pie in the sky... but this is a SAIL boat.

         Please excuse my negativity..... It is not really  meant that way.  Pioneers like yourself blaze the way for those of us who follow later and benefit from what you learn.


  • 21 Nov 2019 23:01
    Reply # 8133712 on 8133077

    I suggest you go to DIYEXPERTS and their article,"Honda EU2200i Inverter generator Review" for lots of data on this machine. It will produce DC directly but not nearly at the same level as AC. See:

    The problem I see with using DC to directly run the motor, is, what do you use for a throttle? I'm sure someone out there who are more conversant on this topic than I.

  • 21 Nov 2019 21:57
    Reply # 8133645 on 8133077
    Jim wrote:

    [...] I intend to buy a Honda EU2200i portable generator, fitted with a three-fuel adapter so it can be run on gasoline, propane of natural gas. According to Electric Yacht, Hobbit can be propelled by a 2Kw generator at 3 knots in calm water, indefinitely. Essentially, we are looking at a hybrid boat [...]

    Hi Jim,

    I will be looking forward to an update on how well you like this solution. I have been thinking about more or less the same system for a few years now.

    I see that the generator you are considering is an inverter generator. I think this means electricity is generated as DC and then converted to AC with electronics insider the generator.

    Does it provide a full-power DC output that can drive the motor directly? I am wondering if you will you need to go from fuel to AC and then back to DC with a power supply or battery charger.

    Last modified: 21 Nov 2019 21:58 | Anonymous member
  • 21 Nov 2019 16:17
    Message # 8133077

    I don't remember what made me decide but decide I did. To take a different direction. Costly but I'm enthusiastic.

    One of the reasons I have been dragging my feet on Hobbit's refit is the fact I hate diesel engines. It seems everyone has a story of grief concerning their diesel. How it broke down in the wrong place at the wrong time. Delays, delays. So many parts. What spares to have on hand? The noise, the smell, the dirt the mess....

    I've decided to remove my Yanmar YSB12 (10Hp) engine and replace it with a QuietTorque 10.00 Sport Electric Motor from Electric Yacht.  48V using eight 6V batteries in series, a type often used in golf carts, from Surrette, known in the US under the brand name Rolls. They are located nearby in Springhill. World wide, they have an excellent reputation.

    (Meanwhile, the engine is in good shape and will hopefully put life back into an ageing Contessa somewhere.)

    Propeller: 13 x 11 x 3, right hand turn.

    My 30' Benford dory has good space for batteries. They will displace the equivalent volume of 25 gallons of water. However, the diesel fuel tank can be modified to carry water. A bladder perhaps. There is another built-in tank meant for kerosene but not used, on the other side which could be used for water.

    I intend to buy a Honda EU2200i portable generator, fitted with a three-fuel adapter so it can be run on gasoline, propane of natural gas. According to Electric Yacht, Hobbit can be propelled by a 2Kw generator at 3 knots in calm water, indefinitely. Essentially, we are looking at a hybrid boat

    Where to store fuel? Working on it. Propane tanks could be stored on fore-deck, attached to forward side of the cabin bulkhead.

    My intended use is local and coastal cruising. Range is limited so one needs to "live within ones means." There will be solar panels. A wind generator, probably not.

    Anyway, it's all very exciting and I feel a renewed enthusiasm for this rather drawn out refit. I think I might try living aboard for a year and sublet my apartment. That will pay for the conversion.

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