Thursday, April 30, 2015

[Electric Boats] Re: New member, new boat, Dowsizing question

 

hi mike, i have an old venture 21 that i've considered making electric. it's basically the same boat as yours, longer of course but only about 6" more beam. i'm interested in how your boat behaves at anchor.


i keep hearing that converting a sailboat to power doesn't work well because the sailboat will "dance" around at anchor. i don't understand why this would be. maybe you can give some anecdotal observation?

i notice the windows on your cuddy seem to be the same type as a venture. did the previous owner cut off the cabin and move it to the stern? neat idea and nice job. i prefer steering from fwd or midship anyway.

the keel on my 21' weighs 400 lbs and has a lead bulb on the end. i've considered using a steel plate or even wood, which is lighter and still will give directional stability when folded under the boat [the keel doesn't retract into the hull]. when down, a heavy keel offers stability in bad weather. 

so, can you tell us how she feels when the seas get up? any worse than a boat designed from the start for power?    thx

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Re: [Electric Boats] New member, new boat, Dowsizing question

 

Thanks for the insight.  
We live and boat on a busy inner city lake with locks, canal and draw bridge passes, a mix of first time boaters, large commercial fishing boats and lot of rowing teams so it can get pretty crazy.  
 Having the little extra power to get out of the way when I need it makes a lot of sense. 

Mike



On Thursday, April 30, 2015 8:03 AM, "Dennis Wolfe wolfeboats@gmail.com [electricboats]" <electricboats@yahoogroups.com> wrote:


 
Mike,  The Venture 17 sailboat was built with 270# of ballast, about four T105s worth.  All the sailing gear might be another 50# so 1000# of batteries is a lot more weight the designer intended. 

Removing half the batteries but keeping the same 48v will let the boat go a little faster, float a little higher and be a little easier to launch and retrieve if you are trailering. All good things. Your range will be a little less than half than what it was with the 16 batteries. That may or may not be a bad thing depending on how you use the boat and availability to plug in to recharge. 

There is absolutely no reason to replace the motor. Electric boats are really about batteries, not so much motors. 

On Friday, April 24, 2015, dellariom@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:
 
[Attachment(s) from dellariom@yahoo.com [electricboats] included below]
Hi all
I am new and just purchased a (one off) electric boat someone else built by converting a Venture 17 sailboat to an electric launch.  He added a Torqueedo Cruise 4 with 16, 6v Trojan 105's (450AH) . The 1000lb battery weight is concentrated in the center of the boat to replace the ballast of the centerboard. He did some creative fiberglass work to move the Cutty Cabin to the aft end which houses a small day head and some resting bunks and converting the forward area into a lounge like the Duffy design. I love the concept of an all day electric boat that makes provision for both battery and bladder needs.

However, I wonder if it is overpowered and wonder if when it comes time to replace the batteries if I could replace the Cruise 4 (8hp-48v system) with a Cruise 2 (5hp-36v system) and reduce the batteries to 6(-620 lbs) or 12(-248 lbs). This would reduce the weight and hopefully increase efficiency? I am however concerned about power reduction and effect on ballast that may be needed to maintain stability. I am obviously not an engineer and hope someone can give me some insight on how to calculate this conversion.

Current Boat specifications are: 
-Estimated weight 500lbs (without batteries and extra little things taken off boat). Original displacement 900lbs
-Length 17ft , Length at Water Line 15ft, Beam 6.5ft, Draft 18in,
-Max Engine size rating 10hp, 
-Current speed is 6.5 mph max with an efficient cruise at 5mph with a Torqueedo calculated range of 80 to 100miles.  

Any suggestion on how to calculate how much power is needed?
Thanks
Mike



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Posted by: Michael Dellario <dellariom@yahoo.com>
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Re: [Electric Boats] New member, new boat, Dowsizing question

 

Thanks Ned
It makes sense that the Cruise 2 will not give me much other than a lighter wallet.  

Your suggestion of higher voltage battery pack seems to make sense but I noticed the Cruise 4 but I noticed they have a High Voltage error message at 65v.  
Do you think10 Trojans charged to say 14v (70v) kick the this error code off?  
Like I said I am still learning. 
Mike



On Wednesday, April 29, 2015 3:26 PM, "Ned Farinholt nedfarinholt@comcast.net [electricboats]" <electricboats@yahoogroups.com> wrote:


 
Mike,
If the goal is to reduce weight, you can remove half the trojans keeping the voltage at 48 volts, or what I would do is use 9 or 10 of the trojans in series for about 60 volts. The Cruise 4 runs better at 60 volts than at 48 since it uses less current for the same amount of power, thereby creating less heat. The Cruise 4 is rated by Torqeedo at 65v. The Cruise 4 will perform just like to Cruise 2 but more efficiently. The significant weight loss with the Cruise 2 purchase would be in your wallet.
Hope this helps.
Ned







On Apr 24, 2015, at 1:40 PM, dellariom@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

[Attachment(s) from dellariom@yahoo.com [electricboats] included below]
Hi all
I am new and just purchased a (one off) electric boat someone else built by converting a Venture 17 sailboat to an electric launch.  He added a Torqueedo Cruise 4 with 16, 6v Trojan 105's (450AH) . The 1000lb battery weight is concentrated in the center of the boat to replace the ballast of the centerboard. He did some creative fiberglass work to move the Cutty Cabin to the aft end which houses a small day head and some resting bunks and converting the forward area into a lounge like the Duffy design. I love the concept of an all day electric boat that makes provision for both battery and bladder needs.

However, I wonder if it is overpowered and wonder if when it comes time to replace the batteries if I could replace the Cruise 4 (8hp-48v system) with a Cruise 2 (5hp-36v system) and reduce the batteries to 6(-620 lbs) or 12(-248 lbs). This would reduce the weight and hopefully increase efficiency? I am however concerned about power reduction and effect on ballast that may be needed to maintain stability. I am obviously not an engineer and hope someone can give me some insight on how to calculate this conversion.


Current Boat specifications are: 
-Estimated weight 500lbs (without batteries and extra little things taken off boat). Original displacement 900lbs
-Length 17ft , Length at Water Line 15ft, Beam 6.5ft, Draft 18in,
-Max Engine size rating 10hp, 
-Current speed is 6.5 mph max with an efficient cruise at 5mph with a Torqueedo calculated range of 80 to 100miles.  

Any suggestion on how to calculate how much power is needed?
Thanks

Mike





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Posted by: Michael Dellario <dellariom@yahoo.com>
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Re: [Electric Boats] New member, new boat, Dowsizing question

 

Mike,  The Venture 17 sailboat was built with 270# of ballast, about four T105s worth.  All the sailing gear might be another 50# so 1000# of batteries is a lot more weight the designer intended. 


Removing half the batteries but keeping the same 48v will let the boat go a little faster, float a little higher and be a little easier to launch and retrieve if you are trailering. All good things. Your range will be a little less than half than what it was with the 16 batteries. That may or may not be a bad thing depending on how you use the boat and availability to plug in to recharge. 

There is absolutely no reason to replace the motor. Electric boats are really about batteries, not so much motors. 

On Friday, April 24, 2015, dellariom@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:
 
[Attachment(s) from dellariom@yahoo.com [electricboats] included below]

Hi all

I am new and just purchased a (one off) electric boat someone else built by converting a Venture 17 sailboat to an electric launch.  He added a Torqueedo Cruise 4 with 16, 6v Trojan 105's (450AH) . The 1000lb battery weight is concentrated in the center of the boat to replace the ballast of the centerboard. He did some creative fiberglass work to move the Cutty Cabin to the aft end which houses a small day head and some resting bunks and converting the forward area into a lounge like the Duffy design. I love the concept of an all day electric boat that makes provision for both battery and bladder needs.


However, I wonder if it is overpowered and wonder if when it comes time to replace the batteries if I could replace the Cruise 4 (8hp-48v system) with a Cruise 2 (5hp-36v system) and reduce the batteries to 6(-620 lbs) or 12(-248 lbs). This would reduce the weight and hopefully increase efficiency? I am however concerned about power reduction and effect on ballast that may be needed to maintain stability. I am obviously not an engineer and hope someone can give me some insight on how to calculate this conversion.


Current Boat specifications are: 

-Estimated weight 500lbs (without batteries and extra little things taken off boat). Original displacement 900lbs

-Length 17ft , Length at Water Line 15ft, Beam 6.5ft, Draft 18in,

-Max Engine size rating 10hp, 

-Current speed is 6.5 mph max with an efficient cruise at 5mph with a Torqueedo calculated range of 80 to 100miles.  


Any suggestion on how to calculate how much power is needed?

Thanks

Mike


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Posted by: Dennis Wolfe <wolfeboats@gmail.com>
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Re: [Electric Boats] New member, new boat, Dowsizing question

 

Mike,

Not sure about the ballast issue but Idoubt you'll have any speed problems by reducing the motor to a 2.0. Power requirements go up exponentially with increase in speed so you'll probaby only lose 1/2 to 1 mph. Try the 4.0 at 50% trottle and see what you get, porbaby not that much less than at 100%. 

To give you a benchmark on "how low you can go" consider this. I'm pushing a 50' long, 20 ton concrete boat 5 mph in calm conditions with an 8 kW input.(That's less than 10 hp)  The speed vs power input for me goes something like this. (48V)

20 amps = 2 mph
40 amps = 3 mph
80 amps = 4 mph
160 amps = 5 mph

Things get a lot slower in heavier seas but surprisingly wind doesn't hurt nearly as bad as you would think. It's was a slow ride and we only averaged about 3 knots but I recently completed a transit of the entire intracoastal waterway of Florida powered exclusively by solar energy. Although the boat can go 5 mph on electric, since my solar array only gives me about 80 amps on a clear day we seldom exceeded 4 mph, unless the tide and wind where giving us a lift. I gotta sip off the batteries real hard to get that last mph so we always tried to save the battery for emergencies, like going thru a bridge when the current can pick up considerable and you want toget thru in a hurry. Although the system worked surprisingly well on partly cloudy days, there are times when it's just so overcast that I will have to switch over to diesel if I HAVE to be somewhere. Not to many night transits on electricity either.

Wind and currents come into play much more when you're underpowered like we are but on a good day with favorable wind and current we often made 5-6 mph. Unfortunately, on bad days, more like 2 mph but I can honestly say we always maintained control of the vessel and the sea never had it's way with us. Although sometimes our travels became frustratingly slow and when faced with these situations we often just dropped anchor until the tides and winds became more favorable. 

I wouldn't recommend underpowering a boat like this unless you have a backup for safety reasons and the Arc is a parallel hybrid with a 38 hp diesel backing up the electric. For the record too, the sweat spot on the diesel is only 5 mph with a max speed of about 7.5 mph but since the darn thing is over 50 years old, I very seldom run it and when I do, I almost never push it past 5 mph.

Capt. Carter
www.shipofimagination.com



On Wednesday, April 29, 2015 5:50 PM, "dellariom@yahoo.com [electricboats]" <electricboats@yahoogroups.com> wrote:


[Attachment(s) from dellariom@yahoo.com [electricboats] included below]

Hi all
I am new and just purchased a (one off) electric boat someone else built by converting a Venture 17 sailboat to an electric launch.  He added a Torqueedo Cruise 4 with 16, 6v Trojan 105's (450AH) . The 1000lb battery weight is concentrated in the center of the boat to replace the ballast of the centerboard. He did some creative fiberglass work to move the Cutty Cabin to the aft end which houses a small day head and some resting bunks and converting the forward area into a lounge like the Duffy design. I love the concept of an all day electric boat that makes provision for both battery and bladder needs.

However, I wonder if it is overpowered and wonder if when it comes time to replace the batteries if I could replace the Cruise 4 (8hp-48v system) with a Cruise 2 (5hp-36v system) and reduce the batteries to 6(-620 lbs) or 12(-248 lbs). This would reduce the weight and hopefully increase efficiency? I am however concerned about power reduction and effect on ballast that may be needed to maintain stability. I am obviously not an engineer and hope someone can give me some insight on how to calculate this conversion.

Current Boat specifications are: 
-Estimated weight 500lbs (without batteries and extra little things taken off boat). Original displacement 900lbs
-Length 17ft , Length at Water Line 15ft, Beam 6.5ft, Draft 18in,
-Max Engine size rating 10hp, 
-Current speed is 6.5 mph max with an efficient cruise at 5mph with a Torqueedo calculated range of 80 to 100miles.  

Any suggestion on how to calculate how much power is needed?
Thanks
Mike





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Posted by: Carter Quillen <twowheelinguy@yahoo.com>
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[Electric Boats] Re: New member, new boat, Dowsizing question

 

wow what a nice job on the hull and deck
mike

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Posted by: mkriley48@yahoo.com
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[Electric Boats] Re: New member, new boat, Dowsizing question

 

Hi Mike,
The original ballast in your Venture hull was there mostly to counteract the heeling forces caused by the sails. If the sails are gone, so are those forces. Your boat would probably float fine with no ballast at all. However, the ballast does add inertia, i.e. resistance to sudden movements, which you feel as a smooth motion in choppy conditions.

If you reduce battery weight, it will make the hull feel a bit livelier, but I think you'd have to remove almost all the weight to make it unstable.

I used to own a Siren 17 sailboat, which only had 130lbs of ballast. It was much more lively than your Venture, but I never capsized it in 10 years of coastal sailing and cruising. It had enough ballast that with the sails stowed, I could stand on the gunwale, one hand on a stay, and lean out, and it was no where near capsizing.

Curtis

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Posted by: cpcanoesailor@yahoo.ca
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Re: [Electric Boats] Controller using torque vs. speed

 

Any chance of a link to the controller ?

Please let us know how much it heats, or not, under max load.
5 minutes should tell you.


On 29/04/2015 20:43, billhopen@yahoo.com [electricboats] wrote:
I just bought a dandy little PWM controller   3000watt  for $15.00.(chinese/e-bay)  it works like a charm, 

--   -hanermo (cnc designs)

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Posted by: Hannu Venermo <gcode.fi@gmail.com>
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Wednesday, April 29, 2015

Re: [Electric Boats] Controller using torque vs. speed

 

Just out of curiosity, does anyone know if the Torqeedo controller works off torque / amperage?

The Torqeedo 4.0 displays Watts used (the 2.0 shows battery voltage, but nothing about the motor).  They also mention NOT to run it dry.  I was initially assuming this was because the motor itself is below the water line - so if you run it dry, there isn't much cooling.

If it was current limited instead of voltage controlled, that would be yet another reason not to run it out of the water.

John

From: "Myles Twete matwete@comcast.net [electricboats]" <electricboats@yahoogroups.com>
To: electricboats@yahoogroups.com
Sent: Monday, April 27, 2015 8:42 PM
Subject: RE: [Electric Boats] Controller using torque vs. speed

 
It'll be okay until you get into choppy water or any other variable load scenario...at that point the motor will accelerate and then suddenly load up ...if your prop is driven via shear pin, you'll be replacing these more often.


Sent from my Verizon Wireless 4G LTE smartphone


-------- Original message --------
From: "luke.wolbrink@gmail.com [electricboats]"
Date:04/27/2015 10:59 AM (GMT-08:00)
To: electricboats@yahoogroups.com
Subject: [Electric Boats] Controller using torque vs. speed

 
Hello,

I'm working on changing to a new controller. After install I learned that with this particular controller the throttle controls the amount of torque. In my previous setup my throttle controlled speed (RPM). What difference will this make when actually in the water? Will I be able to notice at all? On the hard the motor just reved up to max at only about 20% throttle, no load to push agains so it requires almost no power to get to full revs. I'm afraid of what this will be like in the water.

Thanks,
Luke
Tartan 27 #478 "On the Brink"


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Posted by: oak <oak_box@yahoo.com>
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Re: [Electric Boats] Controller using torque vs. speed

 

Controlling speed is by controlling the voltage to the motor.

Controlling torque is by controlling the current to the motor.

With no load the voltage controller will go up to a certain speed.

But with no load the current/torque controller will keep speeding up
to whatever the maximum RPM is at full voltage, slowly or quickly
depending on the control, except at very low settings where the
friction load takes all the [very little] power at some lower point
of RPM.

It's fine in the water because the load goes up with speed and so
there's an equilibrium speed for a given current. Just the continual
speeding up might not be what you expect if testing it dry.

Craig

=====

>Luke,
>
>This should make no difference with you at the helm. A controller that is set
>to control RPM will try to keep that RPM up no matter what power is required.
>One that only trys to keep a set torque will not try to keep the RPM up and
>will better control the power usage. Your speed may not stay consistent but
>the power usage should stay more consistent. Come to think of it you may like
>the results more.
>
>Kevin
>
>On Monday, April 27, 2015 10:59:14 AM you wrote:
>> Hello,
>>
>>
>> I'm working on changing to a new controller. After install I learned that
>> with this particular controller the throttle controls the amount of torque.
>> In my previous setup my throttle controlled speed (RPM). What difference
>> will this make when actually in the water? Will I be able to notice at all?
>> On the hard the motor just reved up to max at only about 20% throttle, no
>> load to push agains so it requires almost no power to get to full revs. I'm
>> afraid of what this will be like in the water.
>
>>
>> Thanks,
>> Luke
>> Tartan 27 #478 "On the Brink"
>
>

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Posted by: Craig Carmichael <craig@saers.com>
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