Electric Trawler

Deck officer, how much power would an array like the one pictured in your post produce. How many batteries would you need, not the lithium but agm's would you need to hold that power in one day. Just trying to get a grasp on what's involved. Thanks

Swampu:

Sunshine has approximately 6 kw total PV array. The size of the battery has more to do with the demand than the replenishment source. Ideally you want the biggest battery that size and budget will allow - this way, with any charging available, you can store the energy.

And, if you are thinking of going this route, forget AGM batteries. Our 400 AH/48v array died after 5 years and they were Odyssey. The cost of ownership is much less for a lithium battery. And to answer your question, how many batteries do you need? One. Just one very big one.

We kept Sunshine disconnected from the grid for the past two months - using her weekends only. The sun kept the battery charged with air conditioning (one 6 kBTU) running 24/7 - along with refrigeration (14 cu.ft. Hitachi), lighting (Imtra LEDs), pumps, hot water, etc. Of course, she is parked in Key Largo, Florida, which helps.

Some Photos of Sunshine

Bob: Here's some photos of Sunshine.

Possible Choice for e-Boat

intjonn said:

Hi; I've just joined this forum and am interested in feedback/info re an electirc powered trawler:

My idea is to buy an 1980's ish trawler; fiberglass; approx. 34' to 38'; no flybridge; something along the lines of a mainship pilot but doesn't need to be one specifically. don't care about the condition of engine or interior per se' but want a solid hull.

Replace engine with a low rpm high torque electric motor and fuel tanks with rechargeble lithium-ion battery bank; install solar panels along with foldout 'wings' for additional solar radiation collection; also install some type of wind generator..........

Thats the basic thesis; would like info on types of motors, batteries; solar panels etc; anyone done this??; etc.

I'm somewaht amazed that in this day where its time to get off fossil fuel that the over a hundred years old idea of larger electric powered boats is not utilized........ intjonn

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Since intjohn started this thread with the idea of buying a suitable trawler and converting to an e-boat, I have a suggestion: the 30' Scout (Elco replica). This is both a handsome and easily-driven yacht with plenty of deck and canopy space for PV. In fact, I have been thinking of doing the same using the Scout as the platform.

rjtrane said:

Regarding your "ugly" comment. I am a great believer in "Beauty is as beauty does."

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As you can tell from my Avitar, I am in total opposition to that philosophy.

Seriously though, the 8.5 X 12.5 rooftop of my pilothouse has always carried solar panels, but now with the removal of everything else, will be totally dedicated to solar. Q. Have their been inroads to panel management systems that can tilt panels to collect the maximum charge? I discussed this back in 1987 when Solarex (Rockville, MD) was one of my main accounts, and there was at least one whole-house system experimenting with this. If one was making passage with a consistent heading in calm water, say from Lauderdale to West End, for example, or one was docked in a marina, would such a system be worth while?

If only....


Imagine the equivalent of a gyro stabilized satellite mechanism (think KVH) - a whole slew of them - each with a light weight PV panel constantly tracking the sun. Perhaps that might work? Or scale up a Texas Instruments DLP chip with each facet holding a single cell?

Since a boat is constantly moving , changing direction, rocking, etc, the only current solution is flat mounted avoiding shadows. Some sort of shore-side tracking could be employed dock-side.

The efficiency of a panel is a factor of the cosine of the angle of the from the perpendicular. If the sun is 45 degrees above the horizon, the panel's potential is over 70%. not a lot of incentive to engineer a tracking system.

Fantastic info on here, thanks to all for sharing your knowledge. I am also interested in an electric/hybrid trawler. Elco is coming out with a parallel system very soon. Here is a full electric river cruiser in Australia that has good performance.
http://www.duckflatwoodenboats.com/pdfs/nomadII.pdf

I waxed enthusiastic musings on another forum a couple of years ago after attending the Dusseldorf Boat Show. Several potential electric hybrid boats were there including the Greenline version, but I really got my tree chopped down about it. Reuben's boat was already making magazine covers, Lagoon was launching a hybrid version of their popular charter cat (featuring the Electric Wheel if I recall), Torquedo seemed to be gaining market share with their outboards, Bob Vincent over at Endeavour was introducing a new electric day boat even while the rest of the industry wallowed in a ditch of downsizing, cutbacks and downright door closings. All we needed was a govt. NASA-like push for battery tech, and I thought sure it was coming. Duh?

When I take a look at the really easy-to-push hulls out there like the PDQ 34, Motorcat 30, Legacy 32, Willard 30, the aforementioned Scout 30, I wonder why it hasn't been tried more often with some of the current efficient designs.

My Admiral and I are paying close attention to battery design. Torquedo came out with a 90 HP outboard some months ago. I know an investment like this will likely never pay for itself, but speaking for the two of us, we're interested in silent cruising in our Manatee. 65 HP would do everything we want to do except range. We need the battery.

Dave,

I enjoyed your link, 13 years ago one of my early projects also used the Etek PM motor. Back then you could buy one for $375, so I bought 2. One has been tortured in EV racing, the other is still unused. It is unused because the first one has never had an issue and still on original brushes.

healhustler,

Very good post. An efficient hull you left out is the Chris White designed Buzzard's Bay. Same length and also a cat like the PDQ 34, but with close to the same power diesels has a top speed of 34 kt. Any Chris White sailboat is an amazing performer, and his power cat is no slouch either. Large outboards will push it to 40 kt, that is flying. I've talked to Chris, and even though his boats are cutting edge, he currently (as of Nov 2012) has no interest in electric propulsion which is too bad.

deckofficer said:

Dave,

Very good post. An efficient hull you left out is the Chris White designed Buzzard's Bay.

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Yeah, that's true, and a good looking boat too. While we're at it, I'd even throw in an Aspen asymmetrical power-cat design, for a single motor application. Thanks for the stimulating boat fodder, by the way.

deckofficer said:

Dave,

I enjoyed your link, 13 years ago one of my early projects also used the Etek PM motor. Back then you could buy one for $375, so I bought 2. One has been tortured in EV racing, the other is still unused. It is unused because the first one has never had an issue and still on original brushes.

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Glad you enjoyed it. After reading that I was very interested in electric propulsion. My original idea was to build this boat Mark V 39
and fit it out with solar panels and electric propulsion. However, I feel I would be limited to rivers and sheltered water.

healhustler,

Thanks for the heads up on Aspen in the PNW. I'm busy going from one link to another learning about this almost local boat. I'm impressed with what I've read so far, quite efficient.

Dave,

I like that Mark V 39. Reminds me of the canal boats throughout Europe the last time I was there. Many are switching to solar-electric because their style of cruising is a perfect fit for that.

I agree, I even ordered the plans for the MarkV 39. Its flat bottom doesnt lend itself well to offshore passages though. But its a good looking boat, the layout is nice and simple and it seems to be an easily driven hull.

Reuben, is there any problem of light reflections from the solar-panel roof in front of the pilothouse? The roof surface in front of my pilothouse is painted a light-tan color and there aren't any reflections to speak of.

healhustler said:

but speaking for the two of us, we're interested in silent cruising in our..stop! 65 HP would do everything we want to do except range.

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What you need to fulfill this dream before you go to the "Great Beyond" is a "sail boat!" It will do everything you've described and with limitless range!

I don't say this to be cute but rather I get a lot of satisfaction out of seeing people achieve their dreams.

Great discussion and contributions guys! I'm learning much about stuff I've considered/wondered about for a while.

While I like the idea of greater efficiency and independence that solar/battery provides, I find the speed, range and time to recharge limitations a bit restrictive. I think we need to consider diesel over electric (like a train locomotive uses) to provide replacement propulsion to recreational cruisers. A small, efficient, properly loaded generator using diesel fuel providing recharging in addition to solar where it fits on the vessel might provide greater speed and range and reduced recharging times.

What do you guys with experience in this area think?

FlyWright,

My neighbor in Sacramento, I'm up in El Dorado. To answer your question, since modern full sine wave inverters provide all the AC you need, a DC gen set for just charging the battery bank is the way to go. Much lighter than AC gen sets and more efficient too. This company has a wide range of DC gen sets. DC Generators & Alternators

Mark,


We have often been asked this question. In all my cruising on Sunshine I recall only one evening motoring directly into the setting sun that there was any reflection from the solar panels. The glass actually has a matte finish.

Regarding diesel electric. In my opinion, in the absence of solar or wind generating power, there is no real fuel savings from a diesel electric power train. The advantages have been mentioned: high torque at low RPMs - small propulsion motor that can tuck under a berth - out the internal combustion generator in a sound shield and locate anywhere in the boat. But, no real fuel savings over a modern diesel.

But, with a big battery and the ability to recharge from renewables and/or the grid and boating expectations that confirm with the limited speed/range using electric propulsion (of course range is extended once you crank up the generator though MPG is no better than pure diesel - speed can be increased with larger motor and either less range or a matching generator of similar power for when you do want to go faster) a serial hybrid could satisfy your needs.

Once you go beyond the low teens in kilowatts for the motor, then you also need to raise the voltage. We sea trialed Sunshine with the Glacier Bay serial system with a pair of 25kw generators and matching 25kw motors running at 240 VDC.

We put 20 group 31 AGM batteries in series to make the 240 v battery bank. With 6 Outback solar controllers we were able to charge shorter strings of batteries (2 ea 48v and 4 ea 36v). After several days of trials in the Pearl River delta, we were disappointed in the performance of the motors - they delivered closer to 18 kw and 9 knots (as I recall). Going to smaller motors at 48v really simplified our lives with top electric speed reduced to 6 knots plus.

Bottom line: any speed with electric motors will either be short (1 hour or less) or require a matching generator running full time.

healhustler said:

Yeah, that's true, and a good looking boat too. While we're at it, I'd even throw in an Aspen asymmetrical power-cat design, for a single motor application. Thanks for the stimulating boat fodder, by the way.

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Thanks again for turning me on to Aspen! I didn't know they existed, let alone the owner/designer's history with efficient hulls and Glacier Bay. I would assume Reuben probably knows Larry Graf. He has taken the little Glacier Bay cat across the Bering Strait, also out to Bermuda, and Hawaii to Guam. His newest company and offering, the Aspen 28' has the most efficient hull for this application I've ever seen, so needless to say a perfect candidate for solar-diesel-electric. I've spent hours following the press, reviews, and videos on this boat. The price is $100K under my budget, leaving room for the hybrid install on a new boat. I think I've spent close to 2 years researching both sail and powerboats, and for my modest needs that 28' Aspen sure comes the closest of any I know of. Proa hull is the way to go, idles with a single 2.0L turbo and intercooled 150 hp diesel at 3 kt with a 0.2 gal per hour fuel burn. The works out to 15 mpg. At 5.7 kt burns 0.9 gal per hour. This sort of under water efficiency is just crying out for diesel-electric propulsion with solar.

For anyone interested Aspen Power Catamarans | 28', 32', 36', 48' Cruising Catamaran
Aspen Power Catamarans Tour Part 2 - YouTube
Thanks again healhustler

Larry has done a great job with his Aspen Cat. He recently lengthened her at the behest of one of our former Island Pilot owners (a type "A" personality who did the Great Loop CLOCKWISE in his IP395). I feel he has made a really nice product. Knowing how weight degraded the DSe, I'm not sure his platform can take the added weight of a sizable battery? On the other hand, there are some nice parallel hybrid packages coming out of Italy that are light with modern, auto-style diesels.

I'm working with a tech company in Istanbul to introduce some parallel hybrid solutions to builders there - both in the yachting world and small commercial fishing arena. Their w/e cruising is much like Miami - a short jaunt to the Princes Island (in the Sea of Mamara), anchor, and return Sunday evening. Even a boat NOT designed for hybrid power can easily make the short run and spend the day or two on the hook and return without cranking up the diesel(s). But, if a longer trip is planned, through the Bosporus to the Black Sea, the diesels give the speed and range needed. A nice compromise.

Reuben,

Weight is the issue on something as small and light as the Aspen. As efficient as the hull is, I would think (16) of the 700 a-hr cells would work at 752 lbs. Some weight would be saved by not needing an AC gen set. But then there is also the weight of the panels and their effect on the vessel's CG.

In all the many tests you have preformed, have you determined the hp a 2.0 L diesel puts out at idle (idle rpm and idle throttle setting)? I can't imagine it being much more than 1 hp.

Solbian makes the lightest panels - pricey since they use Sun Power cells. I feel that the aluminum frame can be removed on typical panels ($1/watt) with a lighter mounting system engineered - my current thinking is to have these unframed panels actually be the roof.

I have NO idea as to idle HP of any motor. My guess is that there are HP/speed curves for the Aspen available?

If you look at the fuel/HP curves of most modern diesels, they hit their sweet spot at RPMs about 1/2 of the max - after the turbo has kicked in. Of course, this is much more than your displacement speed if you're using 2.0 liter motor.

Yep. You save the generator weight but add the hybrid motor and controller weights. Add a good water maker to save on the weight of stored water.

Keep one 12v starting battery for navigation and starting just in case your LI goes down. I like the MeanWell DC/DC converters, too. I have yet to find a good DC/DC charger, though.

Thanks Reuben. I have no trouble finding hp graphs for different rpm, but all are generated at full throttle. The fact that the Aspen at idle (700 rpm) manages 3 kt with a fuel burn of 0.2 gph just had me wondering what shaft hp that was. For the 12 volt systems I'll still go with LiFePO4 for both weight savings and charge acceptance. So much onboard is dependent on that voltage, engine start, lights, bilge pump, windlass, fridge and freezer, electronics, and of course my HAM SSB HF radio that I enjoy so much while boating.

I agree with that sweet spot for diesels. It is the rpm that the engine is at its highest volumetric efficiency, which is at its torque peak which is roughly 1/2 max rpm.

Can't the output of a DC/DC converter be bumped up a bit for charging?

Bob - I tried keeping the DC/DC converters bumped up, but eventually, the batteries that were in line with the converters died. So I just took them off line and recycled them. The only need I have, other than engine starting, is the windlass - it will not work from a power supply alone.

I run most my 12v systems from these converters with are distributed in the four corners of the boat. Since switching to the LI battery, I kept the key navigation gear on a starting 12v battery so I can always find my way home. I'm a neophyte when it comes to LI - only had the battery operational since the first of the year. Once I get more comfortable, I'll rewire the navigation gear to the DC/DC converters with an A/B switch should I need it in the future.

Today we are day tripping on Sunshine in the Florida Keys. 5 knots plenty of sun. Life is good!

Well it is good to see Sunshine isn't just a test bed, that you get out and enjoy her. I guess your 5 kt is all flowing electrons and no dead dinosaur juice?

Reuben,

A couple of years ago I had asked the question on the Cruiser's Forum "Why isn't any diesel engine manufacturers producing small, lightweight turbocharged engines under 50 hp?" That is when I first was made aware of Steyr Motors and their 80 Kg (176 lb) turbocharged 1067 cc engine that produces 36 hp. I believe you are the first person I know using Steyr engines, so have to ask, what was your experience with the company and/or the US distributor? Also if you have the time, how do you like those engines and the engineering of the electric motor interface? You mentioned that you might go with pods next time. Is this for their good vessel maneuverability, or the increase in efficiency due to the 0* angle of the prop?

Diesel Electric propulsion, the Seisventurer is a 90 mtr. 270 ft boat with Diesel Electric propulsion.

The E-motors have a rated power of 1100 kW. The 3 Diesel engines are rated 2480 HP each. Maximum speed 16 kn.

I worked in the design of the E systems of this extremely special boat.

Attached her specs as pdf.

rjtrane said:

Add a good water maker to save on the weight of stored water.

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What powers this water maker that can make water nearly as fast as it is consumed?

A modern watermaker takes about 30 w-hr per gallon and the smaller ones run on 12 volts.