Wednesday, October 31, 2012

[Electric Boats] Re: Conversion of stern drive

 

There are some brilliant guys in the Netherlands that frequent this group.
http://www.newelectric.nl/
Although not as big a project as yours, their install would scale up a bit and fit well depending on your expectations. Not sure if you could run around at planning speed for any real length of time, but low cruising speeds should prove very doable. Be sure to watch their Youtube videos, as they say a picture is worth a thousand words.

http://www.youtube.com/user/NewElectricPowerboat/videos

--- In electricboats@yahoogroups.com, "brent.jaybush" <brent.jaybush@...> wrote:
>
> Has anyone attempted or been successful converting a fairly large stern drive to electric drive?
>
> I have a 1979 26 ft. SeaRay powered by a Mercruiser/Chevy 260 HP 350 CU V8 gas hog with a 100 gallon tank for the black gold.
>
> Just beginning to research the possibilities. Certainly no shortage of space for batteries.
>
> Edison Marine has created a large 17' runabout with enough powering for hull speed, so it seems it should be feasible, perhaps with limitations.
>
> I already run it around MDR at a sea snail's pace using a surplus trolling motor on the swim step, so a proper EV design should do far better, but achieving plane speed is probably out of the question.
>

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Tuesday, October 30, 2012

[Electric Boats] Spam

 

To everyone:

I unfortunately opened Kens email the other day and now my computer had the virus and has sent out the same spam to my address book.  Please do not open any links from Joe that are not signed with the below signature.  Please accept my apologies and I have changed my passwords so there should be no more.  Thanks for understanding and again I am sorry for any inconvenience caused by this.

Keep on Sparkin'

Joe L
 

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Re: [Electric Boats] Conversion of stern drive

 

Brent,

There have been several runabout conversions to electric. See, for example, http://www.boatdealers.ca/reviews/boats/bruce/bruce-22-classic-electric-launch.aspx?LangID=1 Ian Bruce had his boat at the Wye Island Challenge and it will definitely plane. I have built a 19 foot speedster that will do almost 3 times hull speed with a Torqeedo outboard. The secret is to use a very efficient hull optimized for the speed you intend to run and keep the weight down. Keeping the weight down means using lithium batteries. 

On Oct 29, 2012, at 10:40 PM, brent.jaybush wrote:

 

Has anyone attempted or been successful converting a fairly large stern drive to electric drive?

I have a 1979 26 ft. SeaRay powered by a Mercruiser/Chevy 260 HP 350 CU V8 gas hog with a 100 gallon tank for the black gold.

Just beginning to research the possibilities. Certainly no shortage of space for batteries.

Edison Marine has created a large 17' runabout with enough powering for hull speed, so it seems it should be feasible, perhaps with limitations.

I already run it around MDR at a sea snail's pace using a surplus trolling motor on the swim step, so a proper EV design should do far better, but achieving plane speed is probably out of the question.


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Monday, October 29, 2012

RE: [Electric Boats] RPM vs Amps

 

Also on the graphs linked to the prop thrust curve is specific to that prop. Depending on the use of the boat a different prop may be desirable – so where there is a lot of low speed work

 

A blade with a large chord/larger diameter/more surface area per blade, can see the low speed thrust higher while the top end is no higher  as the motor cannot wind out past max efficiency

 

Too small a prop would see a lower levl of thrust achieved over a flatter thrust curve

 

Generally a pitch ratio of approx 1.5:1 (pitch:diam) is the most efficient. More important still is the prop design. Have a look at submarine props – these are very efficient but for the same number of blades, they achieve the same thrust using a larger  diameter, than more traditional shapes.  

 

Yours, 

 

Andrew Gilchrist

fastelectrics.com

Australia

0419 429 201

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Michael Mccomb
Sent: Tuesday, 30 October 2012 4:57 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] RPM vs Amps

 

 

so either his hull is much more efficient or his prop shape is much more efficient or the diameter of his prop is GREATLY influencing the efficiency.....  unless there is some indicator to the contrary i'd have to bet on the latter, prop diameter makes a great deal of difference

 

From: James Lambden <james@toolboat.com>
To: electricboats@yahoogroups.com
Sent: Sunday, October 28, 2012 7:01 PM
! Subject: Re: [Electric Boats] RPM vs Amps

 

 

Hi Dan,

 

Welcome to the world of Electric Boating!

 

For PMAC (Permanent Magnet Alternating Current)  and BLDC (Brushless Direct Current)   motors, which are almost identical, current is torque with a constant, and rpm is voltage with a constant.   When programming the controller, these constants are entered into the program. 

 

As propeller increase in rpm, they demand exponentially more torque for rpm.   So when looking at the motor, you need to look at the application to find out exactly what the curve will be.   This is also dependent on the gear ratio, with lower ratios having a steeper curve than higher ratios.

 

For a good understanding of how these numbers all come together look at the website for our Catalina 30:

 

 

These are real world numbers for our Catalina 30.  Please note that to establish a baseline between all boats, all measurements have been done in zero wind, zero waves, and at either high or low tide.   Furthermore, the measurements are an average of two runs in opposite directions.   

 

Only one boat that I know of has better efficiency than our Catalina, and that is Eric's Cheoy Lee which is running a four bladed prop of slightly larger dimensions.   But we are still working on breaking Eric's record.

 

Cheers,

 

 

James

 

 

James Lambden

Propulsion Marine

325 Chapala Street,

Santa Barbara, CA

93101

 

805 455 8444

 

jlambden Skype

 

 

 

 

 

 

On Oct 28, 2012, at 5:21 PM, dan.randolph wrote:



 

Sorry, this is probably a really basic question, but I am confused so here you go.

From what I have read here, for DC motors, as amps go up, rpms go up in a linear fashion. However in looking at a variety of specifications for motors, they all show RPMs not starting at zero, but actually very high, and then linearly going slightly down with amp increase.

Efficiency usually does a rapid rise to a high point, then a slight drop. Torque is linear rise with amps. But why do the motor spec sheets show the drop from not near zero?

Thanks for indulging a newbie.

- Dan

 

 

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RE: [Electric Boats] RPM vs Amps

 

Dan

 

The graph you originally asked about is the product of  brake dyno. It produces a chart which is opposite to an inertial dyno which is what you usually see for an car engine for example.

 

The motor supplied with full voltage so runs to maximum potential rpm – at which the motor draws a current equal to the torque needed to turn the motor + losses (resistance and induced losses). In this state the motor efficiency is about 5%. Or 95% of the energy that goes in is lost.

 

A brake is applied and the current draw goes up the rpm begins to fall. The key curve to watch is the efficiency line. You want max efficiency point as this is the highest energy return for input. Also for the voltage shown the rpm at which maximum efficiency is reached will always be the same at 100% throttle.

 

The brake is applied sometimes to 50-60% of free running rpm are reached. The reason for the partial curve is that below 60% the motor is extremely innefficeicnt – it does make more torque and consumes far more amps however the motor will only ever be run occasionally at those loadings. Constant running at max power output (50% of peak rpm) or toward maximum torque (0% rpms) will result in heat damage to the motor

 

In most applications the motor is setup so that at max throttle the motor can wind out to a few percent more rpm than those at which max efficiency occurs. You need a dyno chart to establish this accurately. In effect, at less optimal circumstances/higher loadings the motor will run at maximum efficiency   

 

 

 

Yours, 

 

Andrew Gilchrist

fastelectrics.com

Australia

0419 429 201

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Michael Mccomb
Sent: Tuesday, 30 October 2012 4:57 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] RPM vs Amps

 

 

so either his hull is much more efficient or his prop shape is much more efficient or the diameter of his prop is GREATLY influencing the efficiency.....  unless there is some indicator to the contrary i'd have to bet on the latter, prop diameter makes a great deal of difference

 

From: James Lambden <james@toolboat.com>
To: electricboats@yahoogroups.com
Sent: Sunday, October 28, 2012 7:01 PM
! Subject: Re: [Electric Boats] RPM vs Amps

 

 

Hi Dan,

 

Welcome to the world of Electric Boating!

 

For PMAC (Permanent Magnet Alternating Current)  and BLDC (Brushless Direct Current)   motors, which are almost identical, current is torque with a constant, and rpm is voltage with a constant.   When programming the controller, these constants are entered into the program. 

 

As propeller increase in rpm, they demand exponentially more torque for rpm.   So when looking at the motor, you need to look at the application to find out exactly what the curve will be.   This is also dependent on the gear ratio, with lower ratios having a steeper curve than higher ratios.

 

For a good understanding of how these numbers all come together look at the website for our Catalina 30:

 

 

These are real world numbers for our Catalina 30.  Please note that to establish a baseline between all boats, all measurements have been done in zero wind, zero waves, and at either high or low tide.   Furthermore, the measurements are an average of two runs in opposite directions.   

 

Only one boat that I know of has better efficiency than our Catalina, and that is Eric's Cheoy Lee which is running a four bladed prop of slightly larger dimensions.   But we are still working on breaking Eric's record.

 

Cheers,

 

 

James

 

 

James Lambden

Propulsion Marine

325 Chapala Street,

Santa Barbara, CA

93101

 

805 455 8444

 

jlambden Skype

 

 

 

 

 

 

On Oct 28, 2012, at 5:21 PM, dan.randolph wrote:



 

Sorry, this is probably a really basic question, but I am confused so here you go.

From what I have read here, for DC motors, as amps go up, rpms go up in a linear fashion. However in looking at a variety of specifications for motors, they all show RPMs not starting at zero, but actually very high, and then linearly going slightly down with amp increase.

Efficiency usually does a rapid rise to a high point, then a slight drop. Torque is linear rise with amps. But why do the motor spec sheets show the drop from not near zero?

Thanks for indulging a newbie.

- Dan

 

 

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Re: [Electric Boats] Watch those amps!

 

The easy way to keep tools from shorting buses is to install a barrier
between buses. When working in load centres I keep a set of tools
wrapped with electrical tape and make sure I keep that tape without any
wear through spots. The best way is still to install an insulating strip
that is high enough that should a tool drop on one bus it can't come in
contact with the other bus or post ( the wrench becomes a teeter tauter
so to speak). In this way no matter what the working conditions, you
keep a safe ship.

Kevin Pemberton

On 10/27/2012 08:16 PM, Tom wrote:
>
>
> In some installations you can orient the terminals so that a dropped tool isn't long enough to create a problem.
>
> Not so in my installation, so I put adhesive-lined heatshrink tubing
> over the wrench I use for the terminals, leaving only the jaw of the wrench exposed. This is the only tool I use on the cells, unless I put a rubber sheet over the bank.
>
> Years ago I was making the last connection on a battery installation, being very careful to cup the end of the tool in my palm so it couldn't short to anything. What I hadn't considered was that the wrench was making contact with my gold wedding band, and I made contact with something.
>
> The flash was memorable, and the chunk the arc took out of the ring was impressive, but what really got my attention was the heat that was generated. One of the nastiest burns I have had. Rubber gloves have seemed like a really good idea ever since.
>
> -Tom
>
>
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> grip the wrench carefull
>
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> --- In electricboats@yahoogroups.com, Mike <bianu
>> Yes, In my case the cable lug became a fuse and a good thing too!  I would imagine a solid tool like a wrench would not so easily become a fusible link like the lug did . Indeed using solid handled tools requires even more caution around battery terminals.
>>
>> Capt. Mike
>> http://biankablog.blogspot.com
>>
>>
>>
>> ________________________________
>> From: Kirk McLoren <kirkmcloren@...>
>> To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>Â
>>
>>
>> Sent: Wednesday, October 24, 2012 1:27 PM
>> Subject: Re: [Electric Boats] Watch those amps!
>>
>>
>> Â
>> Hello Captain Mike.
>> In the event of a short the only limiting factor is the few milliohms of the wire. It internal impedance of the battery is very small.
>> The resultant current may be many times 200.
>> I have seen wrenches get eaten. Always remove wristwatch and rings before working.
>> Kirk
>> Â
>> To love God in the most practical way is to love our fellow beings.
>>
>>
>>
>> ________________________________
>> From: Mike <biankablog@...>
>> To: ELECTRIC BOATS <electricboats@yahoogroups.com>
>> Sent: Wednesday, October 24, 2012 7:12 AM
>> Subject: [Electric Boats] Watch those amps!
>>
>>
>> Â
>> Well, while I was adding some terminals for a new helm instrumentation project one if the battery interconnect cable  lugs touched the post of the battery next to it for under a second. Thought this group would like to see the result:
>> http://biankablog.blogspot.com/2012/10/mistakes-of-electric-sailor.html
>>
>> Not great harm but, it certainly got my attention. Just a reminder to be careful around those batteries.
>>
>
>

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[Electric Boats] Conversion of stern drive

 

Has anyone attempted or been successful converting a fairly large stern drive to electric drive?

I have a 1979 26 ft. SeaRay powered by a Mercruiser/Chevy 260 HP 350 CU V8 gas hog with a 100 gallon tank for the black gold.

Just beginning to research the possibilities. Certainly no shortage of space for batteries.

Edison Marine has created a large 17' runabout with enough powering for hull speed, so it seems it should be feasible, perhaps with limitations.

I already run it around MDR at a sea snail's pace using a surplus trolling motor on the swim step, so a proper EV design should do far better, but achieving plane speed is probably out of the question.

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Re: [Electric Boats] Fwd:

I clicked on it!  I thought all safe from this forum.  Would someone please explain for a not too computer literate person how to get rid of the curse?


From: Myles Twete <matwete@comcast.net>
To: electricboats@yahoogroups.com
Sent: Tuesday, 30 October 2012 1:39 PM
Subject: RE: [Electric Boats] Fwd:

 
True unless you have good anti-malware protection as I do---in that case your protection system would indicate that the threat was detected and neutralized.
 
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Aaron
Sent: Monday, October 29, 2012 5:32 PM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Fwd:
 
 
If anyone else clicks on the link they are targeted and some how there email starts sending out the same message. one must go and change passwords to help stop it.
 
From: Myles Twete <matwete@comcast.net>
To: electricboats@yahoogroups.com
Sent: Monday, October 29, 2012 12:06 PM
Subject: RE: [Electric Boats] Fwd:
 
 
Moderator note: Apologies to all for this poster's message getting thru.  If you have downloaded it, don't open the link as it is a Facebook spam message.  The message and the poster have been removed from this group in response.  It is rare that this happens, but when it does, you need to know that you risk being removed from our group.
 
 


Posted by at No comments:

RE: [Electric Boats] Fwd:

 

True unless you have good anti-malware protection as I do---in that case your protection system would indicate that the threat was detected and neutralized.

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Aaron
Sent: Monday, October 29, 2012 5:32 PM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Fwd:

 

 

If anyone else clicks on the link they are targeted and some how there email starts sending out the same message. one must go and change passwords to help stop it.

 

From: Myles Twete <matwete@comcast.net>
To: electricboats@yahoogroups.com
Sent: Monday, October 29, 2012 12:06 PM
Subject: RE: [Electric Boats] Fwd:

 

 

Moderator note: Apologies to all for this poster's message getting thru.  If you have downloaded it, don't open the link as it is a Facebook spam message.  The message and the poster have been removed from this group in response.  It is rare that this happens, but when it does, you need to know that you risk being removed from our group.

 

 

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Posted by at No comments:

Re: [Electric Boats] Fwd:

 

If anyone else clicks on the link they are targeted and some how there email starts sending out the same message. one must go and change passwords to help stop it.

From: Myles Twete <matwete@comcast.net>
To: electricboats@yahoogroups.com
Sent: Monday, October 29, 2012 12:06 PM
Subject: RE: [Electric Boats] Fwd:



Moderator note: Apologies to all for this poster's message getting thru.  If you have downloaded it, don't open the link as it is a Facebook spam message.  The message and the poster have been removed from this group in response.  It is rare that this happens, but when it does, you need to know that you risk being removed from our group.




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