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Electric or Diesel-Electric Hybrid propulsion conversion viability


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Ooops. How the heck did I do that :oops: Thanks Kiwi-jon
I was in too much of a rush.
833A is more like it. But that is calculated at 12V, and you would never have a 10Kw motor at 12V. The cable would be bigger than the Cook Strait cable.
Still, it's a sizable chunk of power to get back into the bank.
 

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I'd say easily doable with today's technology (as evidenced by those "doing it"). Just a personal choice as to whether you are prepared to accept the trade off. Obviously KM and MJ aren't, but I would. Not enough to rip out a perfectly good engine yet, but if mine were to blow up and be declared terminal I would most certainly be looking at the full electric option.

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Here are some graphs showing Watts v Knots from three different manufacturers of transom mounted hydro generators. You can also pick up some more hydro generation via regeneration from the drive propeller when under sail.

 

 

Sail-Gen-Graph-1.png

graphique-watt&sea-vEN-cs4-07_0.jpg

courbe_production_hydrogénérateur_save_marine_h240_watts.jpg

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I agree with BP that I wouldn't just rip out a working engine to do a conversion but I started this thread due to the number of dead or near dead engines I have come across and was trying to work out where it might become a viable option to consider. There are plenty of case studies where people have done electric conversions but it will depend on YOUR requirements and the way YOU expect to use it. It certainly isn't a solution for everyone.

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Looking those numbers I think I could easily get the 5:1 ratio mentioned earlier. Like I said I could live with that, others will think differently. But the technology seems to be leaping ahead, be interesting to have another look in a few years.

 

CJ have you looked at the cost of installing an electric drive with batteries vs installing ICE? Thinking replacements again.

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KM, you could also look at from the perspective that the total cost of the actual Uma setup is only USD$1,400 including motor, batteries and solar panels, they use it for no more than 30mins at a time as they like to sail, they have a slightly less than 9hp electric motor that performs closer to an IC engine of double that hp, have reduced maintenance, noise, vibration, smell, complexity of systems, no need to purchase fuel and increased their maneuverability and pleasure in a trade-off for less motoring range which with the savings they made could add a small portable generator and gain back a lot of range if they wanted and still not have spent NZD$3,000. Horses for courses.

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i have to agree with KM. i guess it depends on the boat size and the intended use. Might be a bit painful if used for weekends away and Xmas cruise to the BOI or barrier at 2.7knts. i know in an ideal world we all sail everywhere but the amount of times you end up motoring all the way north or back due to lack of wind happens on a regular basis.

You were looking around the 30 to 35 ft boat size at one stage. The cost of a repower for a boat that size with a new diesel is not that great and the modern diesels are very light and compact.

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Still working the numbers but so far it is appearing that new for new sourced locally from dealers, it is still cheaper to replace a diesel than doing an electric conversion although one offshore dealer has a comparably priced kit but if you put your own kit together and source it from overseas it should be cheaper to do the conversion but the onboard power generation requirements still need to be considered v buying fuel and ongoing maintenance. There are some benefits to be had from going electric that some may feel worth paying extra for if electric suits their needs. You also need to consider the other systems needs on the boat such as electronics, electric windlass, hot water, refrigeration, heating, etc. and how you use them or what you could replace them with and at what cost. It's certainly an interesting exercise to see what's currently possible. 

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KM don't disagree about that but was just showing what money Uma had actually in their system and that it did offer some benefits and was meeting their needs which isn't too bad for the experiment that it is. I certainly wouldn't go down their path though. 

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Personally, I would want to go for LiFePO4 batteries but the cost off the shelf here hurts from what I have seen so far. Putting together something using Winston or CALB 400Ah 3.2V cells should make it more viable with the much better % DOD available to them compared to FLA or AGM. They're around AUD$700 each. Anyone in NZ doing them at a good price?

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I am not going to weigh in on the electric vrs diesel debate here - different people have different wishes and therefore different systems will suit. All I want to add is that in some situations, a well maintained, carefully managed diesel motor can very comfortably run past 20,000 hours, whereas in the exact same installation with poor maintenance, short run times, harder use etc, that same motor could be a very tired motor after 4000 hours. Remember that an average yacht motor does not do that many hours per year, and as a result, maintenance can be casual at best. We have a policy of annual or 250h oil changes - which ever comes first. Rarely does the hour meter dictate that oil should be changed unless there has been a long passage in light winds combined with a skipper who is over doing very little!. 

 

For us, even though we don't tend to do massive hours annually, I would not be changing from a diesel system in the near future, as it would not suit our usage of the yacht, where motor sailing in lighter winds is used to maintain a good VMG.  I would seriously consider a diesel/electric system, however, with a diesel genset and an electric drive,( allowing continuous high power propulsion )   but with only average battery capacity - enough to motor 10 or 15 minutes which we often do in or out of a marina, onto or off the mooring, assisting in the retrieval of an anchor, or, when in tighter places when there is insufficient power being generated by the sails to ensure we have comfortable control or the ease of avoiding other craft. This, however, is how we use the yacht. Others may well have quite a different need, and therefore the system would be quite different.

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Is the overall concept of electric drive not really something that should be looked at on a new build as opposed to a retrofit? Imagine some form of azimuthing, fully retractable drive system, potentially a pair ( one in bow, one stern to give full control when docking ). Being retractable you get no drag when not requiring thrust. The entire design of the vessel would not have to be compromised by siting, and access, to an engine, fuel tank etc. No stern gland to leak. Sailing optimized rudder and keel etc. The benefits are large. The cost, well, I don't know. I still think that the only way to get long range is some form of liquid fuel at present, as even a very high tech, high capacity battery simply won't motor for hours on end at a reasonable speed, and still have plenty of reserve capacity. 

 

With a retrofit, your trying to make an apple into an orange. Is that the best thing to do?

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 Fire , explosion , all thoes are highly related to these type of battery's for marine electric motors , solar panels take up to much room , boats get left sitting to long , battery's don't like salt water , connector don't like salt water , electric motors internals do t like salt water , and these lips cell battery from my usage get very hot , when one gives up it usually explodes Masses amounts of smoke , then fire , the amount of smoke would fill the average bedroom sollid with smoke then fire , and that's only 3 inches long buy an inch either way , energy cell is the only way

 

I think you are confusing Lithium polymer [Lipo]  with the lithium Ion [Liion] batteries that are used in these applications.  Yes Lipo's are volatile, but Liion is comparatively a very stable battery chemistry and fuel in general.

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