Hi Chandler, Welcome to the list! While an electric conversion does have its challenges in terms of cost and performance, I too am very much interested in this approach and would love to go that route at some point and get away from fossil fuel based aux power. I am not sure if or when I will do so as I have a fully functional Westerbeke 20B2 on my C&C 34 and it does have advantages in terms of range and power, but I definitely dislike the noise and vibration and use of fossil fuel. Also from an environmental power while not great, this is a pretty minor contribution to my overall carbon footprint as I only typically go through about 20 gallons a year.
There are people who have successfully done electric conversions on displacement hull boats of this size and vintage. Sailing Uma (youtube channel) https://www.sailinguma.com/electro-beke has successfully made their Pearson 36 and sailing lifestyle work around a limited electric aux propulsion system and solar charging when off grid. They originally used inexpensive and used parts (forklift motor and golf cart batteries) to cobble together a system that got them in and out of the harbor. Later, they upgraded to lithium batteries and more recently a sail drive. From their experience, while the sail drive is cool, I am not sure it makes sense on a boat that was designed with a shaft going through the hull. I think the real key is being willing to plan around your capability in terms of range and speed. If you deal with large tides like here in the north east then pushing against a current for hours might just not be an option with an electric system. So for us, trying to get in and out of our channel for a quick evening sail might not work well if I don't want to time it with the tides. On the other hand if I had an hour or so of range at 4 or 5 knots with some to spare, it would be fine (and I would actually want to design a system with more like 4-6 hours of range at 5 knots) One thing I have been told is that the biggest problem with electric conversions is that while there are lots of components on the market, nobody is building a whole system where they can do the system design and you actually get what you are told. Thus, particularly on newer more expensive boats where the owners are expecting equivalent performance to a diesel, they are getting disappointed. Thus, you pretty much have to design the system yourself and run your own performance numbers since you will be pairing a battery and motor and controller and prop together on your own. There will be some guess work and experimentation involved too and a good understanding of energy and power is important. If I do go down this road, I would want a system with pretty good performance and range (think $) and would likely buy new components so I would expect to put something in the ballpark of 20k into the project (I haven't actually designed and specect a system yet so that is just a rough guess but figure $10k for the batteries (~20 kWh), and $10k for motor (~8 kW), controller, charger. At that point from a pure cost perspective, I suspect a brand new Beta engine would be less expensive. I have wondered about doing a conversion using a (crashed) electric vehicle which might be cheaper and could have significantly better performance - however, i have pretty much decided that a 380 volt DC system isn't great from a safety perspective and the lithium ion batteries require close thermal management which makes things a lot more complicated and they have serious fire concerns so much better off going with lithium iron instead and keeping it to 48 volts I think. The heating water is an interesting challenge too. For short trips if you have shore power ahead of time and a good hot water heater (I have an Isotherm 5 gallon), you can heat it up ahead of time and it will stay hot or at least warm a long time (2 days?). resistive heating will go through the batteries I suspect but perhaps there is a small heat pump type hot water heater available? They make larger ones for houses that are pretty efficient, but not sure about boats. There are propane hot water heaters if you want to keep that fuel on board. And then getting as much solar as possible will be important (on top of conserving power). That also adds costs. Something on the order of 400 - 600 watts might get you 4 kWh of charge on a sunny 12 hour day (sun isn't always overhead) - full recharge over a week? But on the other hand, what does my boat do for 95% of the summer - sit in the sun! Lots to think about but sounds like a great project! Unfortunately, if you are just looking for simple works and you can go when and where you want, the other responses saying get a new Beta diesel probably are the way to go. Nathan S/V Wisper 1981 C&C 34 Lynn MA
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