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Old 07-02-2007, 10:14   #346
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Actually, Tesla & his boss Westinghouse, won the battle over their competitor, Edison, for more good reasons than just voltage transformation.
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Old 07-02-2007, 10:20   #347
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Originally Posted by BambooSailor
Unfortunately, you cannot transform DC (that's why Tesla won the battle over his boss Edisson, remember? ), you need an inverter.
Yes and no...Waypoint has a dc-dc transformer (more properly termed a converter). While not as simple as its ac bretheren, you can buy dc-dc converters. Might be a bear getting high current, though.

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Old 07-02-2007, 18:52   #348
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eLeopard @ Miami

If you're in Miami after the show, why not try out my boat too. Be interested in your views.

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Originally Posted by Quiet Riot 420
POTA

Well said, I could not agree more (the 4300's genset will be running almost all the time, whether motoring or at anchor), but I can see where Tony got his bad impression of batteries, "Waypoint". According to different posts by LtBrett, who has captained "Waypoint" several times, the regeneration capabilities of that Solomon powered boat was only about 10 to 1, as in 10 hours of sailing to get 1 hour of battery motoring, not all that good. Lagoon is claiming to have improved the 420 design so that you get about 1 hour of motoring for every 5-6 of sailing. Of course,the faster you sail the faster the regen. We shall see, as I am due to go out on 420 sea trials the day after the Miami boat show.

Fair Sailing _(\_
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Old 07-02-2007, 19:01   #349
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To Battery or not to Battery

You're right, Lodesman - the house is no different from any other boat. Glacier Bay tells me that, technically, you're right - they could regen.

As for the "elegant" discussion, I'm a fan of keeping things simple. That's what I meant.

As for "regen is good", I came to the view that it does have some very nice properties, but you pay a very considerable "price" for it (not just money).

One aspect is weight: The Lagoon website says that the battery bank on the L420 weighs 1850 lbs. The Onan gen weighs 930, I think. The GB OSSA gen weights 530 (no batteries). That's over a ton heavier. As someone pointed out, not a worry on a monohull, but not good on a cat.

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Originally Posted by Lodesman
I thought about the downsides of the Leopard system too, but house supply would be no different than any other non-hybrid boat; you could use solar or wind at anchor. There really is no reason why the electric motors could not be used as generators under sail. Not having instantly available (and quiet) propulsion is the biggest drawback, but not any different than non-electric boats. I think this system is worth serious consideration - as all things boaty, there are compromises.
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Old 07-02-2007, 19:30   #350
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Green?

On another note, I'm a little perplexed about why people are so ready to assume that REGEN+BATTERIES = GREEN.

There are two issues which concerned me about the battery bank thing. (Disclaimer: I'm not an expert in this, but this is what I picked up):

The first is the difficulty of ensuring correct charging and maintenance of so many battery cells in series. A great deal depends on the design and the charger. If one just uses a standard "smart" charger, then it senses when the battery is nearing full (which means the fastest-charging cell), and drops the power. Then the rest don't get quite charged, and over time, a chemical effect (called sulfation) starts to creep in. The result is decreased battery bank life. And when it comes time to dispose of 12 big batteries, even with recycling, you're not exactly green. And it's pricey!

The second is that, while regen is good, at what point does it start to pull its own weight? (I didn't mean that literally!). I mean: To what extremes are you willing to go for regen? And will you be sailing the distance for regen to produce enough charge for the battery recharge? In other words, is it really worth it?

'cos if not, then you're going to run the gen...in which case...

On my boat, clearly, I'm a charter owner, so distances are short. Easy decision -- to get greener, let's focus on a greener generator first. Focusing on building a hybrid battery design seems to be to be a second-order effect.

Here the story is very, very good.

The OSSA gen is quite a little marvel. 25KW from 530lbs is already a huge breakthrough in W/lb (great for a catamaran application), but we're seeing that the gens are also very abstemious in fuel consumption -- it appears to be a very efficient all-around design.

I'm planning to set up a careful fuel measurement experiment with GB in the near future, but meanwhile, here's what they say about this design:

1. There are no lossy ACC power conversions in this boat for the heavy power hitters -- propulsion, air, etc. The gen is DC and so are the motors. Higher efficiency.

2. DC allows the gen to be variable speed, depending on load. Doesn't run flat-out all the time, as is typical with AC gens -- don't have to maintain 50 or 60 Hz. Doesn't burn fuel unnecessarily.

3. Very efficient diesel: The diesel in the OSSA was developed collaboratively between GB and Mercedes - it's a little 3-cylinder job and I think Mercedes is using it quite a lot in Europe - and it uses common rail injection fueling (see Wikipedia for definition and characteristics). CRI is great for fuel economy, and particularly when the gen is running at less than full load -- it doesn't wet stack (which decreases oil/engine life), as us typical in normal diesels. I'm sure a diesel expert can add a lot more here.

Anyway, we need more scientifically collected data here, and I'm working on it, but I'm very pleased with the green qualities of the OSSA design.

Tony
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Old 07-02-2007, 19:40   #351
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You are right to say that house banks are the same. And if you can balance consumtion with natural input (solar, wind) then there is no difference.

However, if you can't balance your ins and outs (which many can't / don't) then it's a completely different game. On the Leopard you'll be running the genset each day like regular boats. The Lagoon will go days before you have to run the genset. With the larger genset, excess capacity when motor sailing will replenish this supply. On extended sails you'll replenish for free.

What this means is that these boats will appeal to different people with different requirements.
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Old 08-02-2007, 04:54   #352
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Originally Posted by TonyWest
Anyway, we need more scientifically collected data here, and I'm working on it, but I'm very pleased with the green qualities of the OSSA design.
Tony
On that I fully agree. I'm glad you seem as pleased with your Leopard as many of us seem with our L420s. I'm sure we'll see more electric boats come out and see more variations on this theme. An increase in choice is good for the consumers.
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Old 08-02-2007, 06:15   #353
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I have been following the L420. I am curious if anyone on the forum has actually taken delivery of one. I really wanted to go electric on my next boat however I just did not feel that in charter service the systems could be maintained without very high costs to the owners. The problem I see with the 420 aside from maintenance is that the boat seems to be designed more as a motor sailor. It has a very small sail plan relative to its size and windage. Couple that with the extra drag from the large props required for regen and I see a boat that will lose many of the advantages of a cat. I would love to hear what people who have actually used the boat for several months have to say about the boat. The Leopard system appears to allow for folding props and the boat has a bigger sailplan. The boat should be quite a bit faster then the 420. If you take 25% longer to make a 8 hour passage but put two hours of battery run time in the banks from regen have you really gained over the Leopard making the trip in 6 hours? Please don't take this as a negative post on the 420. I am trying to learn and would love to hear counterpoints to what I have posted. I will have the next boat for at least 4 years and will then be looking for an electric boat in what I hope is the future and taking everyone by storm.
George
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Old 08-02-2007, 09:50   #354
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Speculation

Sailvi,

Speculation should end soon as the first L420 are to be released in the next days to weeks. I must disagree with a few (most) of your assertions.

1. The L420 was not designed as a motor sailor. Where did you read that the L420 was a motor sailor? We expect performance to be in line with the L410. All accounts so far have the L420 sailing like most other production catamarans - about Ĺ wind speed.

2. Your position on maintenance is pure speculation. Lagoon has tested this system for four years. If the electronics are stable and no maintenance batteries are used, maintenance costs may be less than an equivalent diesel cat.

3. Please clarify your reasoning for stating that many of the advantages of a cat are lost due to large props? You can keep a low level of power to the props eliminating all drag with minimal fuel consumption. As speed increases you will automatically regenerate. This system is quite remarkable.

As for the advantages of a cat, I believe we will still have a huge, private interior, level sailing, all the comforts of home, shallow draft, excellent maneuverabilityÖ

4. Yes, regeneration will slow you down a knot. If reduced speed is not worth it to you, (to store green energy) then simply turn regeneration off. The props are designed to freewheel. You donít drag a fixed props like a diesel, the props spin freely. It would be a small matter, and consume little energy, to apply a bit of forward thrust to eliminate all drag.

5. I am perplexed why having a huge battery bank on a cruising catamaran would not be considered a great advantage (weight aside). If you seek independence and minimal generator running time having a couple of thousand 12 volt amp-hrs to charge the house bank makes all the sense in the world.

I am in no way putting down the OSSA system. I would prefer this to dual diesels and a generator.

Finally, the issue of weight is just getting old. How is it that so many on this board are better designers than Van Peteghem & Lauriot Prťvost? The catamaran design mantra from the 60ís and 70ís is repeated endlessly. Can you at least consider the possibility that new functional design philosophies exist?

If the catamaran was designed to carry the weight, it will then simply be operating within itís design parameters. Can we give these excellent, proven designers some credit? Maybe they have some understanding of what they are doing considering they have produced a thousand catamarans or so.
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Old 08-02-2007, 10:43   #355
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1. The L420 was not designed as a motor sailor. Where did you read that the L420 was a motor sailor? We expect performance to be in line with the L410. All accounts so far have the L420 sailing like most other production catamarans - about ½ wind speed.

I did not read it was designed as a motorsailor. I should have used another term. For its size it has a very small rig. It looks like the same rig as the Lagoon 410 however the boat is 9000lbs heavier at light displacement! That is a huge increase without increasing the sale area. One mag listed the sail area as 809 sq feet with a 100% jib. This is very small. The Lagoon specs say 1054 but don't say what jib. Between the weight difference and the large props I would not expect the boat to perform anything like a 410.

2. Your position on maintenance is pure speculation. Lagoon has tested this system for four years. If the electronics are stable and no maintenance batteries are used, maintenance costs may be less than an equivalent diesel cat.

You are correct and if it all works well it should be cheaper. I have yet to see a charter company in the Caribbean however that can maintain electrics. One company admitted 90% of their service calls were electrics. How the 420 will play out in charter I don't know. Batteries with life spans advertised at 5 years rarely last more then 18 months in charter.

3. Please clarify your reasoning for stating that many of the advantages of a cat are lost due to large props? You can keep a low level of power to the props eliminating all drag with minimal fuel consumption. As speed increases you will automatically regenerate. This system is quite remarkable.

A conventional boat with folding props will have no real prop drag undersail. Most test reports report the big props cost about 1 knot undersail verses normal props and up to two knots verses folding props. Yes you can motorsail to eliminate prop drag but are you not defeating the purpose of the boat that way?

As for the advantages of a cat, I believe we will still have a huge, private interior, level sailing, all the comforts of home, shallow draft, excellent maneuverability…

All true, with the electric motors you should actually have better maneuverability around the docks with the instant torque.

4. Yes, regeneration will slow you down a knot. If reduced speed is not worth it to you, (to store green energy) then simply turn regeneration off. The props are designed to freewheel. You don’t drag a fixed props like a diesel, the props spin freely. It would be a small matter, and consume little energy, to apply a bit of forward thrust to eliminate all drag.

The speed reductions I referred to verses a regular prop were with the props freewheeling in the test I read. It is however several years old and was not a 420.

5. I am perplexed why having a huge battery bank on a cruising catamaran would not be considered a great advantage (weight aside). If you seek independence and minimal generator running time having a couple of thousand 12 volt amp-hrs to charge the house bank makes all the sense in the world.

It should be a great advantage. You can't have to much battery capacity. The question is how well those batteries will hold up in charter. Only time will tell.

I am in no way putting down the OSSA system. I would prefer this to dual diesels and a generator.

Finally, the issue of weight is just getting old. How is it that so many on this board are better designers than Van Peteghem & Lauriot Prévost? The catamaran design mantra from the 60’s and 70’s is repeated endlessly. Can you at least consider the possibility that new functional design philosophies exist?

If the catamaran was designed to carry the weight, it will then simply be operating within it’s design parameters. Can we give these excellent, proven designers some credit? Maybe they have some understanding of what they are doing considering they have produced a thousand catamarans or so.

I agree, However relative to its weight this boat does not carry a lot of sail.

George
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Old 08-02-2007, 11:12   #356
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Before we go down the road of weight, yet again, please read: Cats, Weight, Performance and Value

These are real world performance numbers, using what we have in terms of weight figures. Frankly, the entire discussion about real world weight is severely -- if not completely -- rendered unreliable because we don't know how much these boats actually weighed, using the same procedure and loads. Manufacturers do not use the same methods and this terribly compromises these discussions. Hang around any boat yard for very long and you will see and hear from various owners their surprise when their boat is actually weighed -- I've heard several be surprised that their boat is actually 1 to 3 tons heavier than they thought. Until we have consistent, reliable data on weight, our ability to say much of anything with confidence is seriously compromised. SA/D ratios are thusly also unreliable. For what it's worth, the Lagoon sail area is quoted with the standard main and standard genoa.
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Old 08-02-2007, 14:13   #357
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Lead and sulfuric acid.

We've had ruminative discussions about the 420 for the last year. It is time to take the leap into the real world. Letís get some feedback from independent owners. Someone take one of these hotrod L420s across with the ARC. Dave, you know itís just a matter of time before those 420 race wins start pouring in.

In response to above:

Electronic components and salt water donít mix but most cruising boats are full of electronic equipment and somehow survive. Agreed, if Lagoon does not properly install excellent quality components we will be in for a big headache.

Battery life is less of an issue to me. A full set of new lead/acids for the L420 is just a fraction of total cost of the boat and readily available. Cruisers who care for their batteries will receive many years of service. I would expect Lagoonís charging systems to be top notch, automated and geared towards charter.

The lithium batteries Lagoon will soon offer have a long life even with 90% depth of discharge. With the same weight of lithium batteries we could double the power storage.

We would need to do an environmental study to determine the relative impact of battery disposal vs. motoring with diesel exclusively over the life span of the batteries. I would expect the marine environment to suffer less when batteries are used and properly disposed. Again, who knows?

A quick word about prop drag. Another trade-off. Big props are more efficient because they can operate at low rpms (I believe more laminar flow, less turbulence and cavitation). This matches the constant torque vs. rpm capability of the electric motors. They also provide superior regeneration. You could efficiently and quietly apply 5-10% power to keep moving in light air. Also, Lagoon said they were experimenting with a feathering prop for the 420.


I suppose I do look at the L420 somewhat like a motor sailor. Given itís tremendous range with the additional tank, you could set a minimum speed and motor sail or sail regenerative across an entire ocean. She will be my familyís floating mobile home, not our race boat but this system might be capable of fast electric/sail passages.

Finally ID, agreed, no more baseless weight discussions. Letís see how she sails in physical water.
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Old 08-02-2007, 15:43   #358
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As I believe I mentioned way back in the much earlier days of this thread, and as Planet describes above, I expect that we will see sailing practices change on the 420 and the boats yet to come. The advantage of "motorsailing" with electrics is having a more consistent speed in higher swell conditions; regenerating when surfing down the wave, giving the boat a bit of a boost going up. When passagemaking, that .5 to 1 knot difference translates to 12 to 24 nm over the course of a day. Not trivial, especially when it comes at little to no net cost in terms of fossil fuel and there is no cost in terms of noise. I imagine we will see other changes, too, such as being able to easily apply a bit of thrust to one motor in order to point a bit higher. On a diesel boat, you wouldn't want to do that unless you absolutely had to, just because of the fuel used and noise endured. On the 420 -- no big deal, just bump the controller a bit forward on the leeward hull. Heck, we may even be able to regenerate on the windward prop while using propulsion on the leeward.

I think we'll see some interesting experiments come out of this.

ID
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Old 09-02-2007, 00:28   #359
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When passagemaking, that .5 to 1 knot difference translates to 12 to 24 nm over the course of a day.

hehe but surely without the weight of these batteries you would be able to sail .5-1 knot faster anyway,
i will however say that if you dumped the lead acids could afford the lithiums and put the electric motors into a lighter composite cat you would be talking
sean
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Old 09-02-2007, 10:33   #360
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Lower voltage means higher current...power remaining the same. Means bigger wires. Means higher losses. Means lower efficiency. Means more heating.

Example
Wire and controller loss of 100 milliohms to motor.

System = 72 volts. Power = 20 kw .1 ohm system loss.
Current = 277.78 amps Voltage drop =27.77 volts
Power at motor = 12.29 KW Efficiency = 61.5%

System = 240 volts. Power = 20 kw .1 ohm system loss.
Current = 83.33 amps Voltage drop = 8.33 volts
Power at motor = 19.31 KW Efficiency = 96.6%

All you did was change the voltage. This is the same reason that the transmission of electricity is done at very high voltages over the nations power grid. Additional factors...The weight and size of the lower voltage motor will be 4 times the 240 volt motor due to the windings required for 277 amps of current---not to mention the added expense. The controller and charging system will be far more expensive, and weigh more, as the current rating needs to be much higher. No one chooses a lower voltage that understands the math and economics.

Battery capacity is not changed...Smaller cells, but more of them, for the same space. Power from batteries remain the same. Higher voltage but less current. 6 cells is not a magic number..it's just what auto's use.

I don't understand any benefit to the Leopard system. Low power, multiple single point failures, cost and weight...versus 2 small diesels in a cat. Even fuel economy...how much of a savings over 1/4 gallon per hour (if I run one engine same HP as the Leopard system)?
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