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Old 27-04-2012, 01:51   #1
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Electric Drive Propulsion for Catamaran

I have taken over the completion of the build of my 36 foot Jaguar Catamaran. As my business is in sustainability and green I am seriously considering installing a dual 10 Kw drive system with diesel generator and 2 200 amp hour batteries.

I am looking for someone who has installed new or retrofit such a system and recommendations on the best tested components
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Old 27-04-2012, 05:29   #2
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Re: Electric Drive Prpulsion for Catamaran

Greetings and welcome aboard the CF, Craigb.
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Old 27-04-2012, 22:07   #3
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Re: Electric Drive Prpulsion for Catamaran

Hi and thank you
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Old 27-04-2012, 22:24   #4
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Re: Electric Drive Prpulsion for Catamaran

craigb,

Welcome to CF, your proposed route for propulsion mirrors mine. I have collected a few links here Integration of systems

And if you find some in your searches, how about dropping a link at the above site.

I'm thinking diesel-electric hybrid whereas one hull has the diesel with motor/generator and the other hull electric motor only, plus batteries and 48 volt 4800 watt inverter.
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Old 27-04-2012, 22:32   #5
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Re: Electric Drive Prpulsion for Catamaran

I have been looking and agree with diesel Generator in serial set up with two Electric motors and like the idea generator and drive in one hull and batteries and drive in other. One consideration I found watching the you tube videos on the Lagoon 410 Hybrid was to consider two smaller generators versus one large one.
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Old 27-04-2012, 22:45   #6
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Re: Electric Drive Prpulsion for Catamaran

The route I hope to go is around 20Kw/hr of lithium batteries in a 48 volt bank for about 40~50 nm silent motoring, but also allow for a fully electric galley from induction stove top to the 1500 watt BBQ on the rail. One diesel only, and when run, fully loaded with both propulsion and 5000 watt DC off the motor for charging. Most all cats have (3) diesels, two for propulsion and one for AC, which will be heavy, rpm dictated by frequency, and thirsty. Generating AC when you already have a 4800 watt inverter is redundant, so no need for a heavy AC gen set.
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Old 04-05-2012, 06:18   #7
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Re: Electric Drive Prpulsion for Catamaran

Craig,
None of the 410's ever had "2 small generators" on board. We all had 15/16KW gensets built by a company in Germany HFL. This was becouse the motors could eat as much as 100A though no one ever did. The Genset would put out roughly 90A at that voltage. I don't know what motors (or one) your looking at so take that into consideration. It may have been the 420 that had the dual gensets, they had a number of control issues trying to coordinate their system where the 410 was much simpler. Dual Gensets would be much more maintenance so I would think a single larger one would be a better idea if you have the room. My 16KW genset has 800 hours on it on an 8 year old boat. I use the single genset for everything from propulsion to A/C. Running at 144V has been no problem and reduces the Amperage to 50A for hull speed.

Steve in Solomons MD
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Old 04-05-2012, 06:39   #8
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Re: Electric Drive Prpulsion for Catamaran

Craig,

so much has been written about hybrid that I am surprised you haven't found all your answers in the existing threads yet. Let me give you my recommendations:

It may be very nice to motor into port silently, but that is not what you need your horsepower for. When you're in lousy weather and are running out of sea room - THAT's when you will need every single watt! So my first recommendation would be to consult with owners of similar sized boats, find out what horsepower they have and whether they think they could get away with a lot less...

Second, all things considered, electric propulsion is neither green nor economic. The Prius excels in start-stop situations, when it can recuperate some of the energy, and when the total power needed is very low. Take it on the Autobahn and it is just a less efficient fuel vehicle - because it carries extra weight and does extra energy conversions. I have about 600 kg of weight in my main battery bank, and if I wanted to discharge them only half, I get the energy equivalent of less than one liter of Diesel fuel (1000 Ah @ 12 Volts * 50% = 6 kWh, energy content of a liter of fuel around 10 kWh). If I run my cat at 6 kts on just one engine, I use about 2.5 l/h. So my batteries could cover that for about 15 minutes...

Fact is, boat engines are used over very long stretches, and 99% of that use is fixed rpm, medium to high power load. And the only thing that counts there is efficiency. And efficiency suffers through each conversion - first you run your generator Diesel, then the generator converts that to electrical, then you transport that to the motors, then you re-convert that through electrical motors to mechanical....

I would say that there is a good reason why no major production builder is going that route anymore - they learned very expensive lessons...

All of that having been said - if you still insist in doing it - let us know how it works...

Best regards

Oliver
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Old 04-05-2012, 07:06   #9
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Re: Electric Drive Prpulsion for Catamaran

Oliver L. speaks as it is so far. Adding electric drive to a diesel layout maybe the better way to go, using it for manoeuvring and fair weather motoring down wind and tide.
Mind you, 2.5 l/hr for 50 hours is a heavy load of fuel. It does need to be offset against the additional battery pack you are carrying to offset the extended electric range.
Solar is good and consistent with the flexi panels, wind fills in when the suns not helping, but in ocean crossing a week of motoring is a minimum, plus the engine running to do cooking and a/c.
Like the hybrid cars, there are no real cost benefits of green power over coal fired electric or diesel for remote operation. Better to consider a large diesel for storm power, and a small QUIET diesel (petrol is quieter) for harbour work and the domestic power generation for all your needs. Keeps Gas Bottles off the boat which must be a plus.
DC Electric drive (or the other linked drive systems) do look attractive but it costs a lot too. Let us know how the things balance out.
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Old 04-05-2012, 07:54   #10
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Re: Electric Drive Prpulsion for Catamaran

First off you need to determine how your going to use the boat.
Day sailor:
Electric drives with batteries and capable of regen would be about all you would need. Solar would be a good addition. It is a sailboat...

Weekend cruiser:
Electric drives with batteries, capable of regen, and solar panels for anchoring out over night. A backup deck genset is used quite often. Most use the Honda 2000 quite well and have the capability to run their motors off it. It is a sailboat...

Coastal/Blue Water Cruiser:
All of the above and a permanent Genset capable of producing all of your needs. It's still a sailboat and if I got stuck out in the middle of the Pacific for a week I'd run the genset to find some wind someplace. I burn 1.2G/hr on my genset alone and could motor 66 hours on the fuel tanks for a range of roughly 600 miles. Add the 5gal jugs and maybe another 200 miles. If there is any sea I will get regen.

First Electric Lagoon Crosses Atlantic to Annapolis...Then Heads to Tortola

For a very friendly and informative group on Electric Boats go to
electricboats : Electric Boats

In my case I spend most of the time on the Chesapeake Bay, probably harder to use an EB on than the open ocean do to lack of higher winds and longer wave periods. Over the last 3 years I used 24G of fuel to, in most cases exercise, run the Genset.
With the advent of LifePo4 batteries on the market I will cut my 1700lb propulsion pack down to 600lb, double the run time to over 6 hours at 6 knots and reduce the pack size by about 1/2. I'll charge in 1/2 the time and have 2 clean engine compartments. It works for me and the way I use my Cat. I believe I have become a better sailor because I SAIL the boat rather than depend on the motors to get around. But then when I need the HP I have it available with a turn of a key and some throttle immediately. I also don't take risks that put me in a situation I need to run the throttles at full bore. By the way the Electric drives are always on while sailing to regen so the throttle is all that needs to be pushed and I can stop the boat running at 8 knots in a boat length. Try that with an ICE motor.
In just 3 years the improvements in Electric systems has been huge. In another 3 years we will see more battery improvements (Lithium/Air??) which will be the game changer. I feel I'm reaping the benefits today.

Steve in Solomons MD
Lagoon 410 SE
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Old 04-05-2012, 08:04   #11
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Re: Electric Drive Prpulsion for Catamaran

One more thing Eleven,
The reason a lot of production manufactures failed was either they didn't run a good system, used inferior parts (cheap batteries in one case), or they had no idea what their client base was going to do with them (put into charter where the renters screwed them up big time.) This is like any new technology, it takes some getting use to and understanding how to run the system to get the most out of it. If you just want to get on board and turn the key then your not going to be happy. Learning how to maintain an EB is different, not harder but different. In some cases it's easier as far as maintenance goes but even the maintenance is different. Take the time to learn your system, like any sailor should, and I think you will be surprised and happy with it. And guys don't get the 420E confused with the 410E, 2 different systems.

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Old 04-05-2012, 08:24   #12
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Re: Electric Drive Prpulsion for Catamaran

Hyperdrive, I am so glad someone has actually put together a system that works.
Cruisers really aught to be able to manage with a system like that, and the new batteries you mention may start to make better and lighter packages than an all diesel system can.
I have never understood why electric cars don't have the roof coated in solar panels, i had seven on my cat and never had any issues with the system. The diesel power was fairly simple but there are just too many parts for it to be considered reliable. What sort of spares do you carry, these things aren't always shelf items?
I am also sure that a diesel electric drive gives a more flexible installation and a more reliable drive.
Enjoy, it must make cruising more of a pleasure.
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Old 04-05-2012, 09:22   #13
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Re: Electric Drive Prpulsion for Catamaran

Eleven,
Cars don't have enough roof area to provide straight Solar Power to the motors. Those guys operate at voltages in the 200 to 400V range and use power at huge quantities to just get rolling. Even boats, including Cats and except some house boats I've seen don't have the roof area to provide enough wattage to run a boat. I'll get a max of 3 panels on my davits (probably only 2) and run around 500w to handle my house loads and get that off my propulsion pack. The Propulsion pack charges the house bank.
The Solomons System I have are actually 2 motors in one so I have 4 motors. I can run off of 1 motor of the 4. I have 4 controllers (1 for ea. motor) I can run off of 1 for the 1 motor. Motors have 1 moving part a $4 bearing I can replace at 200,000 hours. The new controllers are expensive but very durable compared to the older design. I carry 1 spare. The rest of the system is wire and throttle. I have 1 spare (old style replaced with new model) I keep for emergencies but the only thing that could go wrong is if someone steals it. Other than that there isn't anything to go wrong. I have straight shafts with a coupler (have spare) that has been known to break under sever loads and hitting something, I haven't done it but because of the tork involved with electric motors throwing them into reverse under full forward throttle had broken a few of the old style plastic ones on the other 2 boats during charter I might add. I don't have Sail Drives thank God with all the headaches I've heard about them.
One of the 3 sister boats is I believe down in South America now and the other was just sold to someone in New Orleans. All going strong and happy owners. There are a lot of smaller boat owners converting to Electric as mentioned and very happy with the operation. It may be somewhat expensive up front but then the cost savings over time is well worth it. You buy a cheap system and you get what you pay for.

Steve in Solomons MD
Lagoon 410 SE
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Old 04-05-2012, 10:58   #14
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Re: Electric Drive Prpulsion for Catamaran

Quote:
Originally Posted by Oliver L. View Post
..... I have about 600 kg of weight in my main battery bank, and if I wanted to discharge them only half, I get the energy equivalent of less than one liter of Diesel fuel (1000 Ah @ 12 Volts * 50% = 6 kWh, energy content of a liter of fuel around 10 kWh). If I run my cat at 6 kts on just one engine, I use about 2.5 l/h. So my batteries could cover that for about 15 minutes...
Just to point out, converting diesel fuel to mechanical energy through an internal combustion engine wastes ~70% of diesel's energy. An electric motor is much more efficient. Making a straight energy comparison of 'fuel' to mechanical usefulness requires elaboration on the efficiency of each paradigm.

I would venture to guess your battery capacity quoted would be way over a half hour in your example. (given that your diesel engine is only utilizing ~7.5kWh (wasting 17.5kWh) to actually push the boat for an hour)

I do agree with your premise that using current 'off-the-shelf' technology, electric is not as efficient for long term motoring.

Your batteries seem awful heavy. A set of (4) Rolls 12v AGMS @260ah each weigh a total of 312kg.
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Old 04-05-2012, 12:18   #15
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Re: Electric Drive Propulsion for Catamaran

Hi, hyper. The solar panels on the car roof is based on the car starting the day fully charged, doing 20 miles to work (now at 80% battery) then sitting in the sun for 9 hours before another 20 miles home, with headlights. (50%? capacity). Just getting that nine hours of sunlight will extend battery life and maybe allow for a shopping stop on the way home.
I think Cats have many advantages for Electro Power but the larger mono's should be following soon. You are setting a fine example and proving the technology. All the best.
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