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Old 10-24-2008, 07:37 PM   #1
gns
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electric motors....again

As everyone probably remembers, I'm a big fan of diesel-electric systems for boats.* Even though a DE conversion may not make economic sense now, I still think it is an up and coming technology.*

Well, an even better system (to me) would be an all electric system.* I know, I know, current electric motor technology*and especially current battery technology probably isn't up to the task today.* But imagine an electric motor that was half the size and half the weight and twice or more efficient than current motors.* That's exactly what's being developed by companies such as American Superconductor Corporation.* They have completed factory acceptance testing for the world's first 36.5 megawatt (49,000 horsepower) high temperature superconductor (HTS) ship propulsion motor at Northrop Grumman's facility at the Philadelphia Naval Business Center. This is the final milestone before the Navy takes possession of the motor.*
The motor was designed, developed and manufactured under a contract from the U.S. Navy's Office of Naval Research (ONR) to demonstrate the efficacy of HTS primary- propulsion-motor technology for future Navy all-electric ships and submarines. The power and torque of this HTS motor is comparable to the requirements for the Navy's new Zumwalt class of destroyers, known as DDG 1000. In comparison with the conventional copper motors being used on the first two DDG 1000 hulls, the HTS motor is less than one-half the size and weight, and is more efficient over a much wider range of ship speeds. This results in weight and space advantages, enabling an increase in payload capacity for both naval and commercial vessels.

Now I know this is*all still*R&D and it will be a while before it becomes mainstream....and even longer for it to be*miniaturized down to recreational boating size, but the future looks promising for cutting the oil leash.* Imagine a battery bank of 4-8-10 batteries and being able to cruise for a week or so on one charge.*

I got most of the above info here.* You can google HTS motors and come up with a lot more info.* http://www.defensetech.org/archives/003390.html

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Old 10-25-2008, 03:10 PM   #2
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RE: electric motors....again

Gary

Did you see the article in PMM about a guy that converted his boat to DE power? Seems it would be a must read for you. I have the article if you want* information.

Eric Henning
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Old 10-26-2008, 09:00 AM   #3
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RE: electric motors....again

"Now I know this is all still R&D and it will be a while before it becomes mainstream....and even longer for it to be miniaturized down to recreational boating size, but the future looks promising for cutting the oil leash."

Progress is quick , but you may still have a 10- 30 year wait.

We are not on an oil leash , the USA has over 500 years of proven coal reserves that easily change to high quality oil as was done in WWII and South Africa for over 60 years.At $40 a BBL

Now that the Solar Minimum has most folks preparing to relive the "Little Ice Age" (about 300 years last time) the nilists in congress might just allow us to drill the oil from the 85% of the country that is "off limits".

For the lowest cost transportation by boat , simply go sloew (SL of 1) and work a tiny engine hard for efficency.

Simple as that , with ZERO risk of failure.

FF
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Old 10-26-2008, 01:35 PM   #4
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RE: electric motors....again

Your'e missing the point FF. It is'nt that DE is green, it's that it's BETER. It's a better way to drive a boat if you have the money. We've been through this before. It takes as much or nearly as much fuel to power a DE boat as a straight drive boat. Browse the old discussion about DE, engine loading, manervability and other issues. All this is assuming that it works well.

Eric Henning
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Old 10-26-2008, 02:17 PM   #5
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RE: electric motors....again

One obvious advantage would be noise. Battery technologies are improving all the time. An electric forklift today uses much less energy than years ago. Initially, a carbon pile resistor was used to reduce the battery voltage to run the machine at slow speeds. This generated a lot of heat and consumed a lot of energy. SCR control was next. This worked very well for many years but took a bit of technology to shut the rectifier off. This was done many times per second. On off on off. With the on time being a longer duration for faster speeds. To shut the rectifier off once it was gated you had to fire the 2 and 5 rec as I recall to backfeed the cathode on the GE EV1 system. Todays system simply provides gate voltage then removes it to shut it off. Full voltage is accomplished by pulling in a contactor that bypasses the SCR conrol. A normal work cycle for an electric forklift battery is to run 8 hours, charge 8 hours and then cool for 8 hours before starting again. The forklift not only propels itself (a 5000# basic capacity forklift weighs about 9000#'s with battery) but also runs the hydraulic and steering pump motors. These batteries weigh a LOT- a consideration for placement. They probably have a 5 year service life in a forklift so being able to remove them easily in a boat would be a must.Steve
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Old 10-26-2008, 02:30 PM   #6
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RE: electric motors....again

Steve,

GNS used " Electric Motors " in his topic title but talked about DE. Noise would be a wash in DE. One would get added noise from the electric motors and reduced noise from better engine mounting and less vibration .. the latter would prolly have the most effect. Oops .. I see some of the discussion IS about pure electric propulshion. There is no battery that will provide the electrons nessessary .. is there? I tried to fix this thing but* ... failed. Well I see I can add to it but not take away.

Eric Henning


-- Edited by dougd1 at 17:32, 2008-11-10
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Old 11-01-2008, 04:38 AM   #7
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RE: electric motors....again

"It is'nt that DE is green, it's that it's BETER. chow is it better?"

Mostly folks cruise for over 1/2 hour at SL.9 about all electric can do.

3 miles , maybe.

6 at huge expense.
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Old 11-05-2008, 02:55 PM   #8
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RE: electric motors....again

quote,

"Imagine a battery bank of 4-8-10 batteries and being able to cruise for a week or so on one charge.*"

Sorry to bust your bubble but it's not going to happen. It takes energy to move a boat and a battery bank of 4-8 or 10 batteries has only a finite amount. Assuming they could make an electric motor with 100% effeciency, that is to convert all the energy stored in the batteies to moving the boat with no loss, the best you would be able to do would be a few hours of running on a recreational boat let alone a week.

The real problem for what you would like to do is not the electric motor, It's the limited capacity of the batteries. They are getting better all the time...more capacity.. but still have a long way to go.

Dave
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Old 11-06-2008, 03:45 AM   #9
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RE: electric motors....again

"Imagine a battery bank of 4-8-10 batteries and being able to cruise for a week or so on one charge. "

No need to imagine , simply get thee to any diesel submarine , and take a tour.

If you prefer math to dreams compare the energy in 1 lb of diesel and one pound of battery.

Can it be done , sure , but be sure to ask the diesel sub captain the weight of his battset.
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Old 11-06-2008, 05:25 AM   #10
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RE: electric motors....again

I think we should just skip the whole DE/pure electric propulsion idea and go straight to teleportation. Warp drive could be fun, too. Can you imagine the wake!1!!
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Old 11-06-2008, 08:18 AM   #11
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RE: electric motors....again

"Sorry to bust your bubble but it's not going to happen."

"The real problem for what you would like to do is not the electric motor, It's the limited capacity of the batteries. They are getting better all the time...more capacity.. but still have a long way to go."

"If you prefer math to dreams compare the energy in 1 lb of diesel and one pound of battery.* Can it be done , sure , but be sure to ask the diesel sub captain the weight of his battset."

I expected the negative nay sayers, the proponents of staying glued to the past, to show up long before this.* I thought this thread was dead.* *

Of course current battery technology is not up to the task.* But battery tech is expanding all the time.* Imagine a battery that holds 10 times the charge with the same size/weight.* Imagine a battery that can be fully charged in seconds.* Take your*six 600 amp batteries and replace them with*six 6000 amp batteries and see how long you can run.* Better yet, dump your 3000 pound main engine and replace it with*twelve 6000 amp batteries (in addition to the already installed six).* Result is 108,000 amps with the same weight.* Now how long could*you last?* Anchored remotely?* Fire up the small genset and recharge everything in an hour or two.....or maybe even in far less time.* And if the batteries were some type of capacitor based unit, they could last for years and years without replacement.

As I said in the beginning, I <u>know</u> this is all R&D.* I <u>know</u> it's a ways down the road.* I <u>know</u> the current research is*centered on smaller batteries/battery packs that are not remotely applicable to boats.* Nonetheless, new chemistry, new materials, new science, for both motors and batteries will be coming.**It <u>will</u> eventually work its way up to cars and boats.

Researchers at Stanford are working on nano tube batteries.* From "The Stanford Review":
Stanford researchers have found a way to use silicon nanowires to reinvent the rechargeable lithium-ion batteries that power laptops, iPods, video cameras, cell phones, and countless other devices.

The new technology, developed through research led by Yi Cui, assistant professor of materials science and engineering, produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. A laptop that now runs on battery for two hours could operate for 20 hours, a boon to ocean-hopping business travelers.

The greatly expanded storage capacity could make Li-ion batteries attractive to electric car manufacturers. Cui suggested that they could also be used in homes or offices to store electricity generated by rooftop solar panels.

Researchers at Cambridge University and MIT are working on nano tube capacitors.* Capacitors contain energy as an electric field of charged particles created by two metal electrodes. The problem is that storage capacity is proportional to the surface area of the battery's electrodes, so even today's most powerful capacitors hold 25 times less energy than similarly sized standard chemical batteries.

The researchers solved this by covering the electrodes with millions of tiny filaments called nanotubes. Each nanotube is 30,000 times thinner than a human hair. Similar to how a thick, fuzzy bath towel soaks up more water than a thin, flat bed sheet, the nanotube filaments increase the surface area of the electrodes and allow the capacitor to store more energy. Schindall says this combines the strength of today's batteries with the longevity and speed of capacitors.

And MIT researchers are also developing alternative chemical battery technology.* From "Spectrum", the MIT newsletter:
Researchers at MIT have developed lithium nickel manganese oxide electrodes for a new type of battery that offers a charge-discharge rate considerably better than lithium cobalt oxide.* In addition to being four or five times lighter than existing battery packs for plug-ins, the material can be fully discharged and recharged in less time than it takes to read this sentence. We can take all the power in or out of our battery in 10 seconds, Ceder says. You put that in a Prius and it accelerates like a Ferrari."







-- Edited by gns at 09:20, 2008-11-06
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Old 11-06-2008, 10:19 AM   #12
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RE: electric motors....again

Sorry, didnt know I was a nay sayer. Im still waiting for the 200miles/gallon carburetor, cruising a week on batteries alone, etc.

My post was that new technology in motors is not the limiting factor in long range cruising under battery power, its the batteries.

Lets use your nonexistent super batteries and do the math..

My boat requires about 120 HP to move it at 10 MPH

HP = KW / .7457 thus 120hp = KW / .7457 or I need 89.5 KWatts to move my boat at 10 MPH assuming 100% efficiency and no loses.

And the batteries being marine 12 volts

Watts = volts * amps = 12 batteries * 6000 amp/hr * 12 volts = 864000 watts or 864 Kwatts

Therefore, my run time would be 864Kwatts available / 89.5 Kwatts used would be
9.6 hours.

That would get me from Blaine to Roche harbor and back. Still not a week of cruising.

And now to recharge. small generator to recharge everything in an hour or two
Lets do the math..
My generator produces 6 kwatts. Thus 864/6 =144 hours to recharge!!!
That will give me plenty of time to enjoy the bay Im in. Hope FF doesnt mind my generator running all night. And the next day and the next.

I do try to live in the real world and if that makes me a nay sayer then so be it. To achieve what you would like to do will take a quantum leap in technology. I believe that someday it will be possible but doubt it will be in my lifetime.

PS If you could make a 6000 amp/hr battery in the same size as a current 600 amp/hr battery at an afordable price you will be richer then Bill Gates.
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Old 11-06-2008, 11:04 AM   #13
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RE: electric motors....again

Did I say it would be in our lifetime?

To quote myself:
"As I said in the beginning, I <u>know</u> this is all R&D. I <u>know</u> it's a ways down the road. I <u>know</u> the current research is centered on smaller batteries/battery packs that are not remotely applicable to boats. Nonetheless, new chemistry, new materials, new science, for both motors and batteries will be coming. It will eventually work its way up to cars and boats."
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Old 11-06-2008, 03:14 PM   #14
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RE: electric motors....again

"It will eventually work its way up to cars and boats."

The only problem with it working its way up to boats is that no matter how fast this uberbattery may be charged, if you take out*X*power it will still take more than that to recharge it.

Unless you have access to a very large shore power supply on a regular basis, that*means you have to have a large and powerful genset onboard along with all the fuel to run it to take advantage of the ability to charge quickly. If all the power has to come out of a fuel tank there is no point in throwing part of it away in the conversion to electricity to recharge a battery.
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Old 11-07-2008, 07:57 AM   #15
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RE: electric motors....again

Oh no! Another negative Nay sayer!
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Old 11-07-2008, 10:28 AM   #16
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RE: electric motors....again

Hardly negative, I am a great supporter of diesel-electric and other forms of propulsion when applied in the right place for the right purpose. If batteries are recharged from hydro or solar power it can be a "green" source of power. If it is recharged from a coal or oil fired plant then it just displaces the pollution and takes more energy than running a modern diesel to turn the shaft.

It is just simple physics that it takes X power to move X weight X distance in X time, the source of the power is irrelevant.

If the boat consumes 100*horsepower to move it 10 miles in one hour and the trip takes 10 hours you will have consumed 1000 hp-hrs. If that engine is a diesel you probably burned around 350 - 400*pounds of fuel.

If you powered that boat with a battery and electric motor to give the same performance you will consume the same amount of energy. Even with a superbattery of some sort that can be charged in minutes, it will still take more than 350 pounds of diesel fuel to run the generator to recharge that battery. So, unless you have access to a wopping big shore power supply to charge that battery in the short period that its supporters claim makes it worthwhile, the size of the generator you have to carry and the more than 350 pounds of fuel needed to recharge it makes the whole exercise rather pointless in my opinion.
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Old 11-07-2008, 10:40 AM   #17
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RE: electric motors....again

My point too.

Dave
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Old 11-07-2008, 01:15 PM   #18
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RE: electric motors....again

OK,Lets look at this based on some hard battery facts. I just got off the phone with my industrial battery guy and have some values to consider. This will mean more to you engineers out there than me.
<ul>[*]Common forklift battery/*18/25/17, 680 amphour rating. 18(18 cells, 2 volts per cell)/ 25(amps per positive plate)/ 17(plates- positive and negative) Weight is 1920#'s. Six hour Kw rating (volts X amps) is 23.76[*]Common forklift battery/*18/85/25, 1020 amphour rating. Weight is 2750#'s. Six hour Kw rating (volts X amps) is 35.64[*]Common forklift battery/*24/85/17, 680 amphour rating. Weight is 2540#'s. Six hour Kw rating (volts X amps) is 31.68[/list]Steve
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Old 11-07-2008, 01:16 PM   #19
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RE: electric motors....again

Are you both saying that if you can cut fuel useage, say, by half (or even 1/4), it doesn't count because it's still really not green? Since we can't get to the destination in one step we shouldn't bother? I'm not trying to be a smart a$$, I'm trying to understand your logic.

Forget the 7 days of cruising. Use Dave's 9.6 hours instead. Just as a hypothetical exercise. Choice one: run the entire 9.6 hours off the engine. Choice two: run 7 hours on batteries and the last 2.6 hours with the generator running to re-charge the batt set as you go. Are you trying to tell me that saving 7 hours of fuel useage each and every day isn't worth it?

As far as needing some supersized power source, the guys at MIT stated that they can charge their battery (100% ? I'm assuming so) in 10 seconds. They don't mention what size battery they're talking about but they do mention putting such a battery in a car so I am willing to believe that they're talking about something larger than a AA. Since electric cars, when they really start making a presence, will typically be charged at home, and since most every home that I'm aware of has a 110V-200A main service, I'm willing to accept that their battery can be charged in ten seconds from any wall outlet. So, you put a generator with a 200A alternator coupled with a 200A charger and you should be able to charge the batteries just as quickly at sea as at the dock. That's what I see, anyway. What am I missing?

As I see it, you're both trying to trivialize possible future technologies by explaining them with todays (or yesterdays) concepts. Sort of like showing that fractal geometry is impossible by utilizing 17th or 18th century math concepts.
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Old 11-07-2008, 02:00 PM   #20
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RE: electric motors....again

Just because you use a battery does not mean you use less energy to move the boat. It still takes X power to go X miles in X hours. Since you have to recharge the battery in 10 seconds or 10 days it still takes X+ power to do that. A battery only stores energy, it does not make it and it loses energy at every step just like all other energy storage or conversion devices.

"Are you trying to tell me that saving 7 hours of fuel useage each and every day isn't worth it?"

If your diesel genset is large enough to recharge the battery in 2.6 hours as well as drive the boat at the same speed it ran for the previous*7 then you will have consumed more fuel than you would have burned using that engine to drive the shaft directly. You are not saving a single Watt, you are wasting power in the conversions.


"As far as needing some supersized power source, the guys at MIT stated that they can charge their battery (100% ? I'm assuming so) in 10 seconds."

That is precisely why you would need a massive power source ... to replace 10 hours worth of energy use in 10 seconds requires a lot of power. If you want to replace it in 100 hours you can use a small source of power.

"So, you put a generator with a 200A alternator coupled with a 200A charger and you should be able to charge the batteries just as quickly at sea as at the dock. That's what I see, anyway. What am I missing?"

The point that if you are going to recharge at sea you might as well skip the middleman and use that fuel to turn the shaft. There is no free lunch. You will burn more fuel to recharge what you took out of the battery to turn the shaft than you would have burned to turn the shaft with the engine. If you have a 2 megawatt shore power connection or a 2 megawatt diesel genset you can recharge in seconds, a 200 watt supply *just takes*a few days longer, the fuel consumed by either one will be very similar.

"As I see it, you're both trying to trivialize possible future technologies by explaining them with todays (or yesterdays) concepts."

Not trivializing anything. The concepts have been around since the big bang and still apply, always will apply. Read my lips, you lose energy with each conversion.
*
It takes more diesel fuel to recharge a battery that drove a boat 10 miles than you would have used to drive that boat 10 miles with an engine. To make it even worse, this hybrid boat has to carry an engine, fuel, batteries, and motor so it weighs more and takes more power than the same hull with just a diesel and tanks. If you want to spend a day or two recharging from a wall outlet, fine. Just don't kid yourself that it uses less energy. It still uses more,*and it is not "green" unless the electricity comes from solar or hydro.*
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