Saturday, March 31, 2012

Re: [Electric Boats] effective amps based on battery type?

 

More or less,  but you also need to take in to account the Peukert Effect [1]  and the discharge rate that you plan on using the batteries at.  

At high C rates the 160ah lithium batters would probably still have _more_ usable energy then 400ah of flooded Lead batteries.  Maybe slightly less then a 
AGM battery that can go to 60% discharge[2].  But all really depends on you discharge rate.  


On Mar 31, 2012, at 10:30 PM, Michael Mccomb wrote:

 

it's a question....  if one has a 400ah battery bank of lead acid batteries and one can only pull about 40% from them then one is only getting 160ah of actual work right....  wouldn't the equivalent batteries of a lithium type only need to be 160ah to get that same amount of useful work because lithium batteries can be completely discharged?


__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] effective amps based on battery type?

 

it's a question....  if one has a 400ah battery bank of lead acid batteries and one can only pull about 40% from them then one is only getting 160ah of actual work right....  wouldn't the equivalent batteries of a lithium type only need to be 160ah to get that same amount of useful work because lithium batteries can be completely discharged?

__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] Re: Introducing the 'Arc'himedes

 

the sections you have to run where you may encounter adverse currents are Georgia and Carolinas but not for long stretches.
the hudson river and the mohawk river section of the Erie barge canal are capable of more than 6 knots when in a rainy spell.
big danger in getting swept over the dam when trying to get to the locks.  there is around a couple hundred miles in each section that could give you trouble.
Not to say you will encounter  this but easily possible.  Left north carolina in october one year and chopped ice off the deck every night and finally got to Miami 
where it snowed. Conventional wisdom said I should have had 60's and 70's all the way at that time of year. Plan for the extreams not the averages.
I have had a lot of dry stacks if you want help let me know by PM.
mike

__._,_.___
Recent Activity:
.

__,_._,___

Re: [Electric Boats] Battery Investigation cont'd

 

Mike,

  Your not pulling a load from a single battery in a series string are you?

Bob aka "deckofficer"

--- On Sat, 3/31/12, Mike <biankablog@verizon.net> wrote:

From: Mike <biankablog@verizon.net>
Subject: [Electric Boats] Battery Investigation cont'd
To: "ELECTRIC BOATS" <electricboats@yahoogroups.com>
Date: Saturday, March 31, 2012, 3:31 PM



I got back on board after another two weeks away with the Paktrakr disconnected and only the solar panels charging and keeping things charged up. The suspect battery has gotten better in terms of charging and is more in balance with the other three:
Glad I did not pull it out when it first refused to complete a charge as it is now behaving like a normal battery. I'm keeping the Paktrakr disconnected as that seems to have been the cause of the problems over the winter layup.
 
Capt. Mike
 


__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] Battery Investigation cont'd

 

I got back on board after another two weeks away with the Paktrakr disconnected and only the solar panels charging and keeping things charged up. The suspect battery has gotten better in terms of charging and is more in balance with the other three:
Glad I did not pull it out when it first refused to complete a charge as it is now behaving like a normal battery. I'm keeping the Paktrakr disconnected as that seems to have been the cause of the problems over the winter layup.
 
Capt. Mike
 

__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] Torqeedo Cruise 2.0 For Sale

 

Hello,

There is a brand new Torqeedo Cruise 2.0 for sale at a pawn shop here for $1900 with cables and extra propeller. Anyone interested in a Torqeedo electric outboard? Price seems fair compared with West marine where they are $2800.

Steve

__._,_.___
Recent Activity:
.

__,_._,___

Friday, March 30, 2012

Re: [Electric Boats] Re: Electric Sternwheeler

 

I always say to exaggerate the problem when in doubt.


So take a small paddle(like a kid spanking paddle) and move it as fast as you can through water . . . then take a huge paddle and try to move it as fast as you can through water.

It will be slower. Basically it will take a lot more power to move it the same speed.



On Fri, Mar 30, 2012 at 5:44 PM, Kirk McLoren <kirkmcloren@yahoo.com> wrote:


 
...  How beautiful it is to do nothing, then rest afterwards
    

Sent: Friday, March 30, 2012 2:04 PM

Subject: [Electric Boats] Re: Electric Sternwheeler

 
I hope you are right. I would be a shoal water propulsion system, and I was hoping for something a little more scientific!

--- In electricboats@yahoogroups.com, Kirk McLoren <kirkmcloren@...> wrote:
>
>
> bet you a dollar to a doughnut there is more thrust
>
> ...  How beautiful it is to do nothing, then rest afterwards
>  Â Ã‚ Ã‚ 
>
>
> ________________________________
> From: danbollinger <no_reply@yahoogroups.com>
> To: electricboats@yahoogroups.com
> Sent: Friday, March 30, 2012 1:30 PM
> Subject: [Electric Boats] Re: Electric Sternwheeler
>
>
>
>  
>
> Someone correct me if I'm wrong. I thought that drag propulsion is a function of the paddle's immersed float area. Adding more floats (paddles) inline does not change that area (viewed from the stern), therefore, there is no additional thrust.
>
> --- In electricboats@yahoogroups.com, George Field <fieldg63@> wrote:
> >
> > Howabout, instead of a paddle wheel you make a paddle track! Like a tank ttack or a snowmobile belt with paddles attached. Paddles would the travel the length of the boat between the pontoons and back under the deck. You have the option of making the paddles shorter ie not so deep and narrower than a paddle wheel. The paddles would be more efficient as they would be at right angles to the water surface for the whole length of the hull instead of only at the bottom of the stroke on a paddle wheel.
> >
> > Just a thought!
> >
> > George
> >
> > Sent from my iPad
> >
> >
> >
> > On 2011-03-06, at 2:43 PM, "Mooncat" <mooncat_2005@> wrote:
> >
> > > I am planning a paddlewheel boat for use on British narrow canals. She will be 23'6" long (maximum to tow on a trailer behind a private car) 7' beam, with a catamaran hull so the the centre mounted wheel does not project below the bottom of the hull (draft 1',) but has a good flow of water to the wheel.
> > >
> > >
> >
>






__._,_.___
Recent Activity:
.

__,_._,___

Re: [Electric Boats] Re: Electric Sternwheeler

 

 
...  How beautiful it is to do nothing, then rest afterwards
    

From: danbollinger <no_reply@yahoogroups.com>
To: electricboats@yahoogroups.com
Sent: Friday, March 30, 2012 2:04 PM
Subject: [Electric Boats] Re: Electric Sternwheeler

 
I hope you are right. I would be a shoal water propulsion system, and I was hoping for something a little more scientific!

--- In electricboats@yahoogroups.com, Kirk McLoren <kirkmcloren@...> wrote:
>
>
> bet you a dollar to a doughnut there is more thrust
>
> ...  How beautiful it is to do nothing, then rest afterwards
>  Â Ã‚ Ã‚ 
>
>
> ________________________________
> From: danbollinger <no_reply@yahoogroups.com>
> To: electricboats@yahoogroups.com
> Sent: Friday, March 30, 2012 1:30 PM
> Subject: [Electric Boats] Re: Electric Sternwheeler
>
>
>
>  
>
> Someone correct me if I'm wrong. I thought that drag propulsion is a function of the paddle's immersed float area. Adding more floats (paddles) inline does not change that area (viewed from the stern), therefore, there is no additional thrust.
>
> --- In electricboats@yahoogroups.com, George Field <fieldg63@> wrote:
> >
> > Howabout, instead of a paddle wheel you make a paddle track! Like a tank ttack or a snowmobile belt with paddles attached. Paddles would the travel the length of the boat between the pontoons and back under the deck. You have the option of making the paddles shorter ie not so deep and narrower than a paddle wheel. The paddles would be more efficient as they would be at right angles to the water surface for the whole length of the hull instead of only at the bottom of the stroke on a paddle wheel.
> >
> > Just a thought!
> >
> > George
> >
> > Sent from my iPad
> >
> >
> >
> > On 2011-03-06, at 2:43 PM, "Mooncat" <mooncat_2005@> wrote:
> >
> > > I am planning a paddlewheel boat for use on British narrow canals. She will be 23'6" long (maximum to tow on a trailer behind a private car) 7' beam, with a catamaran hull so the the centre mounted wheel does not project below the bottom of the hull (draft 1',) but has a good flow of water to the wheel.
> > >
> > >
> >
>



__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] Re: Electric Sternwheeler

 

I hope you are right. I would be a shoal water propulsion system, and I was hoping for something a little more scientific!

--- In electricboats@yahoogroups.com, Kirk McLoren <kirkmcloren@...> wrote:
>
>
> bet you a dollar to a doughnut there is more thrust
>
> ...  How beautiful it is to do nothing, then rest afterwards
>  Â Ã‚ Ã‚ 
>
>
> ________________________________
> From: danbollinger <no_reply@yahoogroups.com>
> To: electricboats@yahoogroups.com
> Sent: Friday, March 30, 2012 1:30 PM
> Subject: [Electric Boats] Re: Electric Sternwheeler
>
>
>
>  
>
> Someone correct me if I'm wrong. I thought that drag propulsion is a function of the paddle's immersed float area. Adding more floats (paddles) inline does not change that area (viewed from the stern), therefore, there is no additional thrust.
>
> --- In electricboats@yahoogroups.com, George Field <fieldg63@> wrote:
> >
> > Howabout, instead of a paddle wheel you make a paddle track! Like a tank ttack or a snowmobile belt with paddles attached. Paddles would the travel the length of the boat between the pontoons and back under the deck. You have the option of making the paddles shorter ie not so deep and narrower than a paddle wheel. The paddles would be more efficient as they would be at right angles to the water surface for the whole length of the hull instead of only at the bottom of the stroke on a paddle wheel.
> >
> > Just a thought!
> >
> > George
> >
> > Sent from my iPad
> >
> >
> >
> > On 2011-03-06, at 2:43 PM, "Mooncat" <mooncat_2005@> wrote:
> >
> > > I am planning a paddlewheel boat for use on British narrow canals. She will be 23'6" long (maximum to tow on a trailer behind a private car) 7' beam, with a catamaran hull so the the centre mounted wheel does not project below the bottom of the hull (draft 1',) but has a good flow of water to the wheel.
> > >
> > >
> >
>

__._,_.___
Recent Activity:
.

__,_._,___

Re: [Electric Boats] Re: Electric Sternwheeler

 

bet you a dollar to a doughnut there is more thrust
 
...  How beautiful it is to do nothing, then rest afterwards
    

From: danbollinger <no_reply@yahoogroups.com>
To: electricboats@yahoogroups.com
Sent: Friday, March 30, 2012 1:30 PM
Subject: [Electric Boats] Re: Electric Sternwheeler

 
Someone correct me if I'm wrong. I thought that drag propulsion is a function of the paddle's immersed float area. Adding more floats (paddles) inline does not change that area (viewed from the stern), therefore, there is no additional thrust.

--- In electricboats@yahoogroups.com, George Field <fieldg63@...> wrote:
>
> Howabout, instead of a paddle wheel you make a paddle track! Like a tank ttack or a snowmobile belt with paddles attached. Paddles would the travel the length of the boat between the pontoons and back under the deck. You have the option of making the paddles shorter ie not so deep and narrower than a paddle wheel. The paddles would be more efficient as they would be at right angles to the water surface for the whole length of the hull instead of only at the bottom of the stroke on a paddle wheel.
>
> Just a thought!
>
> George
>
> Sent from my iPad
>
>
>
> On 2011-03-06, at 2:43 PM, "Mooncat" <mooncat_2005@...> wrote:
>
> > I am planning a paddlewheel boat for use on British narrow canals. She will be 23'6" long (maximum to tow on a trailer behind a private car) 7' beam, with a catamaran hull so the the centre mounted wheel does not project below the bottom of the hull (draft 1',) but has a good flow of water to the wheel.
> >
> >
>



__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] Re: Electric Sternwheeler

 

Someone correct me if I'm wrong. I thought that drag propulsion is a function of the paddle's immersed float area. Adding more floats (paddles) inline does not change that area (viewed from the stern), therefore, there is no additional thrust.

--- In electricboats@yahoogroups.com, George Field <fieldg63@...> wrote:
>
> Howabout, instead of a paddle wheel you make a paddle track! Like a tank ttack or a snowmobile belt with paddles attached. Paddles would the travel the length of the boat between the pontoons and back under the deck. You have the option of making the paddles shorter ie not so deep and narrower than a paddle wheel. The paddles would be more efficient as they would be at right angles to the water surface for the whole length of the hull instead of only at the bottom of the stroke on a paddle wheel.
>
> Just a thought!
>
> George
>
> Sent from my iPad
>
>
>
> On 2011-03-06, at 2:43 PM, "Mooncat" <mooncat_2005@...> wrote:
>
> > I am planning a paddlewheel boat for use on British narrow canals. She will be 23'6" long (maximum to tow on a trailer behind a private car) 7' beam, with a catamaran hull so the the centre mounted wheel does not project below the bottom of the hull (draft 1',) but has a good flow of water to the wheel.
> >
> >
>

__._,_.___
Recent Activity:
.

__,_._,___

[Electric Boats] Re: Electric Sternwheeler

 

That's what I heard to, for large tows at slow speed.

--- In electricboats@yahoogroups.com, "Byron Evetts" <h2ologged@...> wrote:
>
> Memory serves from my naval architecture class that paddle wheelers have
> more pull than props.
>
>
>
> Byron
>

__._,_.___
Recent Activity:
.

__,_._,___

RE: [Electric Boats] Re: addition to electric boat forum

 

Thanks for your comments Eric. I think we are much more in agreement than otherwise.  Longer more easily driven boats ups the efficiency of hauling people and gear around and significantly ups the cost too. I do have significant experience in the field, with a background in working with s couple of the big names in multihulls and many articles and speaking engagements on multihull building practices behind me. I have also built and cruised several large multihulls as well.  

   For whatever payload you envision on a boat, devise ways to minimize the weight and bring all the gear inside the boat. Larger streamilined boats are ever so much more efficient in the elements than smaller boats with gear mounted all over the cabin-tops and more. Windward performance is an important safety feature that is not so hard to achieve with the right cruising philosophy.

 Owners should consider building larger boats that are not finished to the yacht caliber, rather than nicer smaller boats. The ocean does not care if your boat looks like fine furniture and fishermen the world around laugh at the yachties that have spent a year of more on the paint preparation of their boats, just to be bashed around at sea. While I like fine finishes,  performance and suitability are prime requirements.

  I invented, patented  and marketed a quick-build system for multihulls for many years (Mastermolding) and persons that want larger more easily driven boats can research the systems that built big boats cheaply and quickly. My boats would match the windspeed up to about 15 knts and they were not so very expensive. But they were great to sail and did not need to motor much at all. I remember one three month cruise in which I never refilled my 10 gallon petrol tank, and I covered all the Bahamas and the Florida keys. For whatever distance one travels, less food, fuel is needed in efficient boats, and proportionally less motor power is needed for the payload.

  Another point about larger, lighter boats is the navigational advantages. Tides and course planning is quite a lot easier, the currents that you can sail against (how often they are against you!) are much less vexing, and arguably enjoyment is greater. Sailing with the tides is actually a lot more complicated than just waiting for the tidal turn, often one has to punch thru a bit of contrary current to get on the right side of that equation.

  Lastly, sea motion and safety are so much improved on larger boats, and I accept your estimation of ideal sizing of the craft. The elements dictate what our lives are going to be like on the water, and my experience tells me that many that are converting heavy ballasted boats to electric are putting lipstick on a pig. Jace

 

________________

Jace Hobbs

P: +64 3 5451122

M: +64 21 051 1666

www.electricbikehub.co.nz

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Eric
Sent: Friday, March 30, 2012 9:46 PM
To: electricboats@yahoogroups.com
Subject: [Electric Boats] Re: addition to electric boat forum

 

 

Hi Jace,

You make some interesting points, though I have to say that I never converted a car to electric that started out weighing more than 1000kg in ICE form, even 20 years ago when we didn't have sophisticated drives available.

The main reason that most electric boat conversions are done with displacement type hulls is their superior weight tolerance. Even with Lithium batteries, electric drives are noticably heavy.

You state that getting a boat into the 8 to 12 knot range is easy. When was the last time that you sailed a boat at 10 knots?

I have an F-27 8.5m trimaran that uses "modern design and engineering" (it's actually 22 years old) that I have sailed at 17kts, but until the true wind gets past 12-14kts, my average speed is close to 7kts. I had the opportunity to convert to electric, but even the weight of a small electric drive (8kWh battery pack with a Torqeedo Cruise 4.0) would have been a performance penalty that I wasn't willing to accept. If you have sailed a fast boat, imagine adding a 110kg passenger that never leaves the boat. For any performance boat under 10m, that's a considerable penalty.

You'll find that for multihulls, you need to go big (expensive) to get enough weight capacity to carry an electric drive while maintaining reasonable performance. Of course, these larger boats need more powerful drives, which weigh more, which affects performance, and you're into the vicious cycle of weight and power. The lower threashold that seems to work occurs somewhere around a 12.5m cruising catamaran (not a light racing catamaran).

And as you've already alluded to, a ballasted keel boat needs LWL to get to 8 kts. You'll need at least 11m at the waterline for an 8kt hull speed. But it's been my experience that a performance ULDB keelboat needs about 14m of waterline before it can average 8kts for more than a few minutes at a time. With a light 16m boat weighing in at 10 tons, it needs a more powerful drive and bigger batteries, which weigh more, etc. etc.

So what you're saying is easy to write, but much more difficult to execute in the real world. Since few of the members here have $100,000 - $200,000 or more to spend on their boats, the 8.5-10m auxilary sailboats deliver very successful conversions at a reasonable price. They may not develop much in the way of regeneration, but if you talk to the people that have actually converted their boats, little regen is not really a problem.

If you've got some more specific details about your concept, please share them, there's enough practical experience in this group to vet the concept without having to build one from scratch.

Fair winds,
Eric
Marina del Rey, CA

PS. I have been working with a group of people, including Pete Melvin (lead designer of the new AC45 and AC72), that are slowly trying to develop an electric offshore power cat with a range of 100nm at 12-15kts. It's a lot harder than it sounds.

--- In electricboats@yahoogroups.com, "Jace Hobbs" <jacehobbs@...> wrote:
>
> It strikes me that almost all of the conversion projects that people are
> involved with are on boats with slow hull speeds that make the mild
> horsepower less attractive and make the regen argument a non-starter. This
> reminds me of electric car conversions that started with a heavy antiquated
> chassis because it was available cheaply. Poor performance in the cars and
> boats is the result.
>
> To get efficiency, we must look at the whole system approach, and that
> starts with the boat we will convert. Weight and hull form (inextricably
> connected) must be prime considerations. The cheap hulks that we cram our
> lovely electronics into perhaps don't deserve the upgrade as they will
> disappoint with short range and low average speeds.
>
> The regen situation puts this in high relief, because getting a boat in
> the 8-12 knot range is easy today if you use modern designs and engineering.
> Often this means going to an unballasted boat (usually a multihull) but it
> surely means advanced building techniques to keep the structure with little
> wave inducing drag. With the higher sailing speeds easily produced, the
> regen suddenly makes sense. Cheers
>
>
>
> ________________
>
> Jace Hobbs
>
> P: +64 3 5451122
>
> M: +64 21 051 1666
>
> www.electricbikehub.co.nz
>

__._,_.___
Recent Activity:
.

__,_._,___