Saturday, January 23, 2021

[electricboats] Our 39’ electric hybrid sloop is for sale

Hello all, Our dear boat is for sale.  I put in an electric hybrid system this past summer and we love it.  We are moving to land and unfortunately can’t have both.  Here is the link to our Craigslist ad: 
https://seattle.craigslist.org/see/boa/d/seattle-comfortable-and-unique-cruiser/7266211916.html
This group was such a huge help to me getting this project done and I’ll be forever grateful.  I can’t wait to do another one.  

Cheers!
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Tuesday, January 19, 2021

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

I have a pair of 10kW 48v Motenergy PMAC motors from Thunderstruck on my 12m cat Sunshine. Since this was a repower I had good trials data from 3 sources: 1) tank test. 2) first trials with 25kW motors. 3) final trials with diesels & 7kW motors. 


looking carefully at all the data up to max speeds resulting from 10kW/motor - prop sizes and prop rpm - I was able to make my choices for reduction (3:1) & prop size (18”x14” 3-blade). 


during sea trials we were able to max out rpms at 2,400 (motor RPM) AND amps at 200. Speed was 6.3 knots. I feel our max cruise is 6 knots - we seldom go faster than 4 knots. 


the reason the tank test and original trials had better performance is they were both done with “as designed” displacement.  the final boat was quite a bit over weight - thus the less efficient performance.  If I were to build another, I’d make sure we hit our target weight - that would result in a 7 knot cruise speed with the same pair of 10kW motors.

 

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Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida

My pulleys and the chain link thrust bearing have rusted significantly. I tried painting the pulleys and have also slathered the thrust bearing in rust prevention lubricant but it has not worked. Any advice on what does work is appreciated. 

On Jan 19, 2021, at 14:23, William Shannahan via groups.io <shannahanwilliam=yahoo.com@groups.io> wrote:


Yeah the pulleys on mine are rusting while the actual mount is not.

Sent from my T-Mobile 4G LTE Device


From: electricboats@groups.io <electricboats@groups.io> on behalf of THOMAS VANDERMEULEN <tvinypsi@gmail.com>
Sent: Monday, January 18, 2021 12:55:41 PM
To: electricboats@groups.io <electricboats@groups.io>
Subject: Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida
 
What I found interesting was to note which components of the T'struck system were rusting and which weren't.  T'struck recommends painting all the non-stainless steel parts in the datasheet packed with their reduction units.  But they're not specific as to whether or not that should include the pulleys.  From the photos of this boat, it appears that they should be!  [And ohmigosh ... mildew on the stainless motor mount plate?  Really sad photos.]
[-tv]

Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida

Yeah the pulleys on mine are rusting while the actual mount is not.

Sent from my T-Mobile 4G LTE Device


From: electricboats@groups.io <electricboats@groups.io> on behalf of THOMAS VANDERMEULEN <tvinypsi@gmail.com>
Sent: Monday, January 18, 2021 12:55:41 PM
To: electricboats@groups.io <electricboats@groups.io>
Subject: Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida
 
What I found interesting was to note which components of the T'struck system were rusting and which weren't.  T'struck recommends painting all the non-stainless steel parts in the datasheet packed with their reduction units.  But they're not specific as to whether or not that should include the pulleys.  From the photos of this boat, it appears that they should be!  [And ohmigosh ... mildew on the stainless motor mount plate?  Really sad photos.]
[-tv]

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

At full throttle my Thunderstruvk 10kw kit draws 150-190a, I've never seen it go above 200. I used a 600a fuse. 

On Jan 19, 2021, at 13:26, Myles Twete <matwete@comcast.net> wrote:



Yes, double the power for each 1kt increase in speed.

Current (and power) depend on prop loading---go slow, use small or use shallow pitch prop or use a pack voltage that is too low and you won't reach the current limit.

I don't use a brushless motor/controller, but the physics is the same.  I first used the stock 9.9" prop on my outboard.  If I still was using that, I probably wouldn't reach 200amps (@40-48v) due to inability to spin it fast enough to load it.  Since I'm swinging a 12"x12" prop, the loading is much greater with speed and at 48v, my controller draws 200amps.  If I were still running 36v lead-acid, I'd probably only get to 120amps.  Again, not a TS brushless kit.

 

YMMV-

 

-MT

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of THOMAS VANDERMEULEN
Sent: Tuesday, January 19, 2021 8:30 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

 

Ryan and Reuben:  Has anyone reported actually drawing 200 amps with their Thunderstruck 10kw motors?
I was just reviewing the data provided under another recent topic here, "New Prop 10kw Motor", posted by Peter running his Catalina 30 tall rig, Zephyr.  His table stated that in calm seas and running in excess of 5 knots, or roughly 75% of hull speed for a Catalina 30, he was using just over 100 amps
As has been stated in various topics here on this forum, drag increases at roughly the square of speed (depending on hull form, of course), so if Peter were to push closer to hull speed, power usage would increase.  But double?
I haven't yet committed to the main battery cables I'll actually be installing on my boat, hence my curiosity: was there a reason you mention 200 amps as a maximum to think about for the T'struck 10kw motor?
[-tv]

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

Yes, double the power for each 1kt increase in speed.

Current (and power) depend on prop loading---go slow, use small or use shallow pitch prop or use a pack voltage that is too low and you won't reach the current limit.

I don't use a brushless motor/controller, but the physics is the same.  I first used the stock 9.9" prop on my outboard.  If I still was using that, I probably wouldn't reach 200amps (@40-48v) due to inability to spin it fast enough to load it.  Since I'm swinging a 12"x12" prop, the loading is much greater with speed and at 48v, my controller draws 200amps.  If I were still running 36v lead-acid, I'd probably only get to 120amps.  Again, not a TS brushless kit.

 

YMMV-

 

-MT

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of THOMAS VANDERMEULEN
Sent: Tuesday, January 19, 2021 8:30 AM
To: electricboats@groups.io
Subject: Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

 

Ryan and Reuben:  Has anyone reported actually drawing 200 amps with their Thunderstruck 10kw motors?
I was just reviewing the data provided under another recent topic here, "New Prop 10kw Motor", posted by Peter running his Catalina 30 tall rig, Zephyr.  His table stated that in calm seas and running in excess of 5 knots, or roughly 75% of hull speed for a Catalina 30, he was using just over 100 amps
As has been stated in various topics here on this forum, drag increases at roughly the square of speed (depending on hull form, of course), so if Peter were to push closer to hull speed, power usage would increase.  But double?
I haven't yet committed to the main battery cables I'll actually be installing on my boat, hence my curiosity: was there a reason you mention 200 amps as a maximum to think about for the T'struck 10kw motor?
[-tv]

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

Ryan and Reuben:  Has anyone reported actually drawing 200 amps with their Thunderstruck 10kw motors?
I was just reviewing the data provided under another recent topic here, "New Prop 10kw Motor", posted by Peter running his Catalina 30 tall rig, Zephyr.  His table stated that in calm seas and running in excess of 5 knots, or roughly 75% of hull speed for a Catalina 30, he was using just over 100 amps
As has been stated in various topics here on this forum, drag increases at roughly the square of speed (depending on hull form, of course), so if Peter were to push closer to hull speed, power usage would increase.  But double?
I haven't yet committed to the main battery cables I'll actually be installing on my boat, hence my curiosity: was there a reason you mention 200 amps as a maximum to think about for the T'struck 10kw motor?
[-tv]
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Monday, January 18, 2021

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

I have a few comments regarding your suggestions. 


1. A 10kW motor will draw max 20”A at 50v. And most likely will never be run at that much load. I’d say 200A for the fuse. 


2. Wire size depends on the total run, to and from the load. 2/0 wire gives you 1% voltage drop at round trip of 30’. A round trip of 15’ is #2 wire with 1% voltage drop  I use a free app, Wire Sizer to calculate the size. Round trip means total length for the positive and the negative wires added together. 


3. If you’re using a $250A fuse, then with 2/0 wire your round trip reduces to 24’. 

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Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida

What I found interesting was to note which components of the T'struck system were rusting and which weren't.  T'struck recommends painting all the non-stainless steel parts in the datasheet packed with their reduction units.  But they're not specific as to whether or not that should include the pulleys.  From the photos of this boat, it appears that they should be!  [And ohmigosh ... mildew on the stainless motor mount plate?  Really sad photos.]
[-tv]
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Re: [electricboats] New prop 10KW motor _Prop specs

I got the prop dimensions

 

Dia is 12"

Pitch is 5"

 

I don't know what the reduction is as my equipment came as a package from Electroprop.

Rgds  Peter

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of Peter Zephyr via groups.io
Sent: Monday, January 11, 2021 2:53 PM
To: electricboats@groups.io
Subject: Re: [electricboats] New prop 10KW motor

 

Displacement is 10,200 Lbs

LWL= 25'

Max Beam=10.83'

Prop is 3 blade fixed.   I don't know the Dia or pitch off hand but will try to get it this weekend.

See attached photo of prop

 

Rgds  Peter

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of THOMAS VANDERMEULEN
Sent: Monday, January 11, 2021 11:42 AM
To: electricboats@groups.io
Subject: Re: [electricboats] New prop 10KW motor

 

Peter,
Great table of data ... thanks!
Please remind us what the displacement, LWL, and Max beam are of the Cat 30; and also provide prop specs (dia x pitch) and type (2, 3 blade, folding, feathering, etc).
Thank you!
[-tv]

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

[Edited Message Follows]

Hi rholden;

Before you spend any money, spend some time watching the youtube videos from Pacific Yacht Systems. Sit through the multi-part electrical systems seminar. You'll get a quick overview of most of the issues.

A quick summary to answer your question about fuses:

The fuse (or circuit breaker) protects the wire. Each wire can withstand a certain amount of power being transmitted through it before it is likely to fail. "Failing" means catastrophically melting and setting fire to your boat so you want to avoid that. Your goal as you design your electrical system is to have a fuse between the power source and the load for almost every wire in your system (there are exceptions for the alternator on a gas/diesel motor and a few other specific things). Because the fuse protects the wire you want the fuse physically located as close as you can to the power source.

You also want to size the wires you're using so they're appropriate for the load. Each load in your system will have a maximum draw rated in amps. The wire should be rated to carry MORE than that amount of amps. The tradeoff is cost; the larger the wire, the higher the cost. You COULD run battery cable to every load in your boat and you'd have a super-safe boat. But the cost (and weight) will kill you.

So you design your system in reverse. Start with the load. Let's say you have an electric motor that can draw up to 200 amps at 48V. You need a wire that can carry MORE than 200 amps. Doing the calculations you'll end up with AWG 2/0 wire. One end of the wire is connected to the motor controller. The other is connected to the source - your battery bank. Close to the source, you should have a fuse rated at more than 200 amps, but less than the carrying capacity of the wire. (You may end up with a 200 amp fuse for all sorts of reasons, and you'll probably be ok running the motor at 200 amps but you'd build in some margin for error if you had a 250 amp fuse in that circuit instead).

Generally speaking you want 1 fuse for every load. Practically speaking that means that you will connect a fuse box or circuit breaker panel to your source; you'll fuse the wire from the source to the panel, and then fuse each wire from the box/panel to its load.

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Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

Hi rholden;

Before you spend any money, spend some time watching the youtube videos from Pacific Yacht Systems. Sit through the multi-part electrical systems seminar. You'll get a quick overview of most of the issues.

A quick summary to answer your question about fuses:

The fuse (or circuit breaker) protects the wire. Each wire can withstand a certain amount of power being transmitted through it before it is likely to fail. "Failing" means catastrophically melting and setting fire to your boat so you want to avoid that. Your goal as you design your electrical system is to have a fuse between the power source and the load for almost every wire in your system (there are exceptions for the alternator on the motor and a few other specific things). Because the fuse protects the wire you want the fuse physically located as close as you can to the power source.

You also want to size the wires you're using so they're appropriate for the load. Each load in your system will have a maximum draw rated in amps. The wire should be rated to carry MORE than that amount of amps. The tradeoff is cost; the larger the wire, the higher the cost. You COULD run battery cable to every load in your boat and you'd have a super-safe boat. But the cost (and weight) will kill you.

So you design your system in reverse. Start with the load. Let's say you have an electric motor that can draw up to 200 amps at 48V. You need a wire that can carry MORE than 200 amps. Doing the calculations you'll end up with AWG 2/0 wire. One end of the wire is connected to the motor controller. The other is connected to the source - your battery bank. Close to the source, you should have a fuse rated at more than 200 amps, but less than the carrying capacity of the wire. (You may end up with a 200 amp fuse for all sorts of reasons, and you'll probably be ok running the motor at 200 amps but you'd build in some margin for error if you had a 250 amp fuse in that circuit instead).

Generally speaking you want 1 fuse for every load. Practically speaking that means that you will connect a fuse box or circuit breaker panel to your source; you'll fuse the wire from the source to the panel, and then fuse each wire from the box/panel to its load.

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Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

For a 48V 10kW system, the maximum battery current is 250A-300A.
It is the controller that limits the current consumption.
The fuse protects the battery against short circuits, so it must be as close as possible to the battery.
Thierry
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Sunday, January 17, 2021

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

Bank size is really more related to what use case you envision.  I day sail a 27ft Catalina on the Chesapeake with perhaps 20 minutes of power usage then sail with another 20 minutes coming home.  I've run some tests that show about 1.5hours at about 35amps using 40% of the bank. The 100ah bank of agm batteries weigh about 270 pounds and adding another 270 pounds on a boat that size creates balance issues.  I'd love to switch battery chemistry but the cost to just too high.  Number of recharge cycles and depth of discharge certainly favors lithium batteries but for me it don't need it.  My bank is 2 years old and when it's time to replace I hope to change but I'll do the cost benefit analysis again then.

John

On Sun, Jan 17, 2021, 9:10 PM Ryan Sweet <ryan@ryansweet.org> wrote:
If you have not installed your system yet, I strongly encourage to consider going with a larger battery bank if you can. 100ah will not last very long with the 10kw motor. 

On Jan 17, 2021, at 17:33, Carsten via groups.io <Carstensemail=yahoo.com@groups.io> wrote:


The correct formula is W / V.

Many electric boaters refer to Amp use, but it is best to provide the Watt use, as the voltage of a system may not always be 48V.

Carsten


On Monday, 18 January 2021, 07:56:35 GMT+8, rholden@orcon.net.nz <rholden@orcon.net.nz> wrote:


I have a Thunderstuck that I intend to install on my 28ft yacht. New to all this and trying to get this done and installed safely.

Basic question but on this setup with the 48Volt 10KW - I assume I have to install some fuses between the battery pack ( 4 X 12VOLT 100AMP Deep Cycle) and motor and possibly other places in the system to protect equipment and humans.
What is the Amperage of the fuses needed?? Is the calc V / W = AMP??
Where would you install any fuses in this kind of system?
Thanks all.

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Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

OK take your point on the Amp Hour storage  - currently, I have 4 small 20AH batteries to test the system - so once running I will look further at capacity / range as Thunderstruck recommend a minimum of 100AH



On Mon, 18 Jan 2021 at 15:09, Ryan Sweet <ryan@ryansweet.org> wrote:
If you have not installed your system yet, I strongly encourage to consider going with a larger battery bank if you can. 100ah will not last very long with the 10kw motor. 

On Jan 17, 2021, at 17:33, Carsten via groups.io <Carstensemail=yahoo.com@groups.io> wrote:


The correct formula is W / V.

Many electric boaters refer to Amp use, but it is best to provide the Watt use, as the voltage of a system may not always be 48V.

Carsten


On Monday, 18 January 2021, 07:56:35 GMT+8, rholden@orcon.net.nz <rholden@orcon.net.nz> wrote:


I have a Thunderstuck that I intend to install on my 28ft yacht. New to all this and trying to get this done and installed safely.

Basic question but on this setup with the 48Volt 10KW - I assume I have to install some fuses between the battery pack ( 4 X 12VOLT 100AMP Deep Cycle) and motor and possibly other places in the system to protect equipment and humans.
What is the Amperage of the fuses needed?? Is the calc V / W = AMP??
Where would you install any fuses in this kind of system?
Thanks all.



--
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Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

If you have not installed your system yet, I strongly encourage to consider going with a larger battery bank if you can. 100ah will not last very long with the 10kw motor. 

On Jan 17, 2021, at 17:33, Carsten via groups.io <Carstensemail=yahoo.com@groups.io> wrote:


The correct formula is W / V.

Many electric boaters refer to Amp use, but it is best to provide the Watt use, as the voltage of a system may not always be 48V.

Carsten


On Monday, 18 January 2021, 07:56:35 GMT+8, rholden@orcon.net.nz <rholden@orcon.net.nz> wrote:


I have a Thunderstuck that I intend to install on my 28ft yacht. New to all this and trying to get this done and installed safely.

Basic question but on this setup with the 48Volt 10KW - I assume I have to install some fuses between the battery pack ( 4 X 12VOLT 100AMP Deep Cycle) and motor and possibly other places in the system to protect equipment and humans.
What is the Amperage of the fuses needed?? Is the calc V / W = AMP??
Where would you install any fuses in this kind of system?
Thanks all.

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

The correct formula is W / V.

Many electric boaters refer to Amp use, but it is best to provide the Watt use, as the voltage of a system may not always be 48V.

Carsten


On Monday, 18 January 2021, 07:56:35 GMT+8, rholden@orcon.net.nz <rholden@orcon.net.nz> wrote:


I have a Thunderstuck that I intend to install on my 28ft yacht. New to all this and trying to get this done and installed safely.

Basic question but on this setup with the 48Volt 10KW - I assume I have to install some fuses between the battery pack ( 4 X 12VOLT 100AMP Deep Cycle) and motor and possibly other places in the system to protect equipment and humans.
What is the Amperage of the fuses needed?? Is the calc V / W = AMP??
Where would you install any fuses in this kind of system?
Thanks all.

Re: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

Look at the wiring diagram for the thunderstruck kit.  Battery bank goes to sevcon controller and there is a 450 amp fuse at the front end of the circuit 

John



Sent from Samsung tablet


-------- Original message --------
From: rholden@orcon.net.nz
Date: 1/17/21 6:56 PM (GMT-05:00)
To: electricboats@groups.io
Subject: [electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

I have a Thunderstuck that I intend to install on my 28ft yacht. New to all this and trying to get this done and installed safely.

Basic question but on this setup with the 48Volt 10KW - I assume I have to install some fuses between the battery pack ( 4 X 12VOLT 100AMP Deep Cycle) and motor and possibly other places in the system to protect equipment and humans.
What is the Amperage of the fuses needed?? Is the calc V / W = AMP??
Where would you install any fuses in this kind of system?
Thanks all.

[electricboats] Fuse Setup for 10KW Thunderstruck motor on 28FT Herreshoff

I have a Thunderstuck that I intend to install on my 28ft yacht. New to all this and trying to get this done and installed safely.

Basic question but on this setup with the 48Volt 10KW - I assume I have to install some fuses between the battery pack ( 4 X 12VOLT 100AMP Deep Cycle) and motor and possibly other places in the system to protect equipment and humans.
What is the Amperage of the fuses needed?? Is the calc V / W = AMP??
Where would you install any fuses in this kind of system?
Thanks all.
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Friday, January 15, 2021

Re: [electricboats] Electric and regen under sail

I found that fascinating.  hadn't considered how the dual setup allows the props to have clear water flows that make regen more efficient.  amazing what you can do when designed to be electric from the start.

Beautiful boat too...
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Thursday, January 14, 2021

Re: [electricboats] Electric and regen under sail

It's nice to see a somewhat purpose built electric sailboat! 

They were regenerating 1kw PER motor at 8 knots! 


Matt Foley 
Sunlight Conversions
Perpetual Energy, LLC
201-914-0466



On Thursday, January 14, 2021, 04:38:56 PM EST, Ryan Sweet <ryan@ryansweet.org> wrote:


So on the recent topic of regen, the latest Uma video profiles a  design from Solana yachts, 46ft, with a dual oceanvolt setup with feathering props. In the video they demo regen of up to 1kw coming into the system when sailing at 8kts. 

It's a really fun video, and does talk some on the motivation to electric in the first place. 


[electricboats] Electric and regen under sail

So on the recent topic of regen, the latest Uma video profiles a  design from Solana yachts, 46ft, with a dual oceanvolt setup with feathering props. In the video they demo regen of up to 1kw coming into the system when sailing at 8kts. 

It's a really fun video, and does talk some on the motivation to electric in the first place. 


Wednesday, January 13, 2021

Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida

That boat is mess but did anyone else notice the alpha gen 36/48 volt generator onboard? I wonder how many amps that can deliver and if it allows the boat to run on it for an extend time.
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Re: [electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida

probably another 10k to move it out of hell 

On Wed, Jan 13, 2021, 8:19 AM Bill Farina <bill@thirdcoast.us> wrote:

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[electricboats] 1984 C&C 29' Sailboat - 2015 Electric Thunderstruck Motor - Florida

Tuesday, January 12, 2021

Re: [electricboats] New prop 10KW motor

As long as the "water force on the prop" is greater than the "throttle input", it should regen?

 

It's not that simple.

Let's say you throttle up and are cruising at 5knots and that it takes 1kw to do so.  Then the wind comes up and you transition to sailing and you are able to throttle back.  As that happens, at some point the prop may be driven backwards and regen 'could' occur.

Without knowing the specs on the controller, the motor and the prop, we can't say much more than this.  We DO know that there's roughly a square relationship between power required and speed for a displacement craft.  And that's a square loss both ways.  If it takes 1kw to drive the boat 5knots, you should not expect more power in regen than sqrt(sqrt(1kw)), or less than 6watts.  That's a trivial amount of savings.  Far greater is the savings you get by simply being able to throttle down, saving power significantly.

 

May I take this one step further?  What happens if at the same time you are solar generating say at 10 amps and regen at 5 amps?  Would this simply add up to 15 amps charge?

 

Sure, that's a start.  But it depends.  If the regen current alone causes your pack voltage to get near its rated peak, you'd expect regen current to "back off" if another source also pushes charging current into the pack.  And assuming that BOTH of these respect voltage limits, then it's a race condition, but suffice it to say that no, it will not simply add to 15amps of charge.  Now, IF that happens, you could consider pulling out of regen by pushing the throttle forward until you maximize power from the solar panels while getting greater speed due to less drag.  Overall, a win-win.  A similar thing should be considered if running a genset with battery charger while underway.  As you begin 'sailing', the throttle requirements drop.  As that happens, the pack voltage rises (especially if you are using lead-acid batteries) and that leads to the charger(s) detecting max charging voltage and backing off on charge current.  And that can cause the genset to back down.  This can result in waves of up/down current and genset speed.  Again, if speed is of value, it might be best to increase your throttle to the point that "net" current draw from the pack is zero or some acceptable level of net draw---pack stays charged and you're essentially just running on generated power.  I've done this.

 

Would the expected regen current at say 500 rpm be roughly the same as the current required to push to 500 rpm - minus friction and "throttle input" ?

 

As noted above, no.  Again, let's say you need 1kw to spin the prop 500RPM.  We know there is a square relationship between power and speed.  Sqrt(1000) = 31.6

Now, you are driven by the wind and the prop is now spinning 500RPM backwards.  We expect, due to this square law, sqrt(31.6) or 5.6watts of power might be able to be captured.

Now, the devil is in the details.

We know that a prop's loss is greater with speed and load.

So, if the water is spinning the prop at 500RPM, while the speed is the same, the load depends on the motor/controller and would ideally be set to deliver max power to the pack (e.g. via MPPT).  Still, I can't imagine in this scenario that you'd be able to get more than 5% of the power that it took to drive the prop at the same speed.  I'd like to be wrong… J

 

In case this helps…

 

-MT

 

 

From: electricboats@groups.io [mailto:electricboats@groups.io] On Behalf Of Mich Pop
Sent: Monday, January 11, 2021 1:44 PM
To: electricboats@groups.io
Subject: Re: [electricboats] New prop 10KW motor

 

Hi everybody

 

Thanks, Thomas, for that great explanation.

Am I correct assuming that the same applies to an induction motor?

As long as the "water force on the prop" is greater than the "throttle input", it should regen?

 

May I take this one step further?

What happens if at the same time you are solar generating say at 10 amps and regen at 3

5 amps?

Would this simply add up to 15 amps charge?

 

Would the expected regen current at say 500 rpm be roughly the same as the current required to push to 500 rpm - minus friction and "throttle input" ?

 

 

Cheers

Mich

 

On Tue., 12 Jan. 2021, 03:05 THOMAS VANDERMEULEN, <tvinypsi@gmail.com> wrote:

Carsten and Peter:
The amount of regenerated power, as Peter suggests, would be approximately the NET of the amount generated less the amount input.  If you've tried turning the motor shaft by hand, you've observe that it seems to want to "step" through its rotation.  This is the effect of the alternating resistance and attraction felt as the permanent magnets on the rotor pass by the stator windings.  To free-wheel a sailboat propeller, power is sent to the motor in order to energize the stator and overcome the latent resistance.  Once the resistance if equaled, the additional force of the water passing by the prop will turn the motor faster than it would otherwise be turning given the low power input, and -- voila -- the motor becomes a generator, transforming the surplus of energy into electricity flowing back into the battery.
I see this same effect in my battery-electric Chevy Bolt when coasting, and especially when going downhill at moderate speeds.
Although I haven't seen any scientifically oriented research to support it, my thought is that in an electric boat scenario, it makes more sense to have a three or four-bladed prop, as large as will comfortably fit the boat and with moderate pitch to allow some amount of regeneration with the ability to make the prop "transparent" as Matt stated earlier (clever metaphor, Matt!) when sailing at slower speeds.  Two-bladed, variable pitch, and folding props simply won't work as well *because* they're lower drag!
Have I tested these thoughts and theories out in practice ... NO, not yet!!  But I'll be back with you on the topic later in the Great Lakes sailing season!
[-tv]

Re: [electricboats] New prop 10KW motor

Mich,
(1.) Candidly, my understanding of the regen topic is entirely practical and lacks a solid theoretical basis, so I'm not able to answer your first question (re: induction motors). 
(2.) Similarly, I'm not confident of an answer to your second line of inquiry concerning adding in solar to the mix of inputs,  The engineers reading this will be able to affirm or correct my thought on this, but assuming the currents you're referring to are at the same voltage, then, yet, I believe they would simply add together.  If your solar is at 12 volts, to be stepped up, and regen is at 48 volts, the the arithmetic is different.
(3.) Finally, lacking a thorough theoretical grounding, my answer to your last question concerning the equivalency of currents in or out given a particular RPM is more of logical surmise that a statement of fact.  However, I would NOT expect the current generated at 500 RPM to be approximately equivalent to the current needed to turn the prop at 500 rpm.  [We're talking prop shaft rotation, presumably.]  I would expect the current generated at 500 rpm to be significantly less than the current needed to turn the prop at 500 rpm.  [Maybe another reader has the authoritative data on this question.]

PROPELLER AS TURBINE? - Another point to make in this discussion concerns the effectiveness of a marine propeller when acting as a turbine.  One author I read stated flatly that marine propellers fail as turbines due to their design and blade orientation.  It makes sense to me that they would be far less effective at being driven by water passing over them than they are at driving through the water.  Certainly, our propellers are drive us better forward than they do in reverse.  That same source observed that to make your propeller effective as a turbine, you'd have to be able to reverse pitch by 180 degrees.  Indeed, the Finnish electric propulsion company, OceanVolt, has developed and patented a pitch reversing propeller for their saildrive units that they claim is twice as effective at generating power while free-wheeling under sail.
Nevertheless, some people continue to report being able to generate some amount of power via free-wheeling.of their traditional sailboat prop.  And if it's practical to make your prop "invisible" with net zero output and the potential for a few extra watts incoming -- with no extra investment or equipment -- then it seems like a no-brainer to me.
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Monday, January 11, 2021

Re: [electricboats] New prop 10KW motor

Hi everybody

Thanks, Thomas, for that great explanation.
Am I correct assuming that the same applies to an induction motor?
As long as the "water force on the prop" is greater than the "throttle input", it should regen?

May I take this one step further?
What happens if at the same time you are solar generating say at 10 amps and regen at 3
5 amps?
Would this simply add up to 15 amps charge?

Would the expected regen current at say 500 rpm be roughly the same as the current required to push to 500 rpm - minus friction and "throttle input" ?



Cheers

Mich

On Tue., 12 Jan. 2021, 03:05 THOMAS VANDERMEULEN, <tvinypsi@gmail.com> wrote:
Carsten and Peter:
The amount of regenerated power, as Peter suggests, would be approximately the NET of the amount generated less the amount input.  If you've tried turning the motor shaft by hand, you've observe that it seems to want to "step" through its rotation.  This is the effect of the alternating resistance and attraction felt as the permanent magnets on the rotor pass by the stator windings.  To free-wheel a sailboat propeller, power is sent to the motor in order to energize the stator and overcome the latent resistance.  Once the resistance if equaled, the additional force of the water passing by the prop will turn the motor faster than it would otherwise be turning given the low power input, and -- voila -- the motor becomes a generator, transforming the surplus of energy into electricity flowing back into the battery.
I see this same effect in my battery-electric Chevy Bolt when coasting, and especially when going downhill at moderate speeds.
Although I haven't seen any scientifically oriented research to support it, my thought is that in an electric boat scenario, it makes more sense to have a three or four-bladed prop, as large as will comfortably fit the boat and with moderate pitch to allow some amount of regeneration with the ability to make the prop "transparent" as Matt stated earlier (clever metaphor, Matt!) when sailing at slower speeds.  Two-bladed, variable pitch, and folding props simply won't work as well *because* they're lower drag!
Have I tested these thoughts and theories out in practice ... NO, not yet!!  But I'll be back with you on the topic later in the Great Lakes sailing season!
[-tv]

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Re: [electricboats] New prop 10KW motor

Displacement is 10,200 Lbs

LWL= 25'

Max Beam=10.83'

Prop is 3 blade fixed.   I don't know the Dia or pitch off hand but will try to get it this weekend.

See attached photo of prop

 

Rgds  Peter

 

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of THOMAS VANDERMEULEN
Sent: Monday, January 11, 2021 11:42 AM
To: electricboats@groups.io
Subject: Re: [electricboats] New prop 10KW motor

 

Peter,
Great table of data ... thanks!
Please remind us what the displacement, LWL, and Max beam are of the Cat 30; and also provide prop specs (dia x pitch) and type (2, 3 blade, folding, feathering, etc).
Thank you!
[-tv]

[electricboats] 6 Pack Captain ticket

Happy 2021
My nephew Wayne Talbot fishes rod and reel out of Jerusalem with a commercial license for his side gig. 2020 was not his year, as the first day of the season his boat  sank at the dock the night after launch.  By fall after insurance delays and reflection, he is in a newer larger center console and a new engine.
Now he wants to go for his 6 passenger Captain certification and reached out to me for advice.
Any Club members have recommendations?
Thanks,
Bob Lee
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Re: [electricboats] New prop 10KW motor

Can you post data for your Rawson 30?  Please include boat specs? 

I'd like to see this info any time someone posts data...
Boat type
LOA
LWL
Beam
Displacement
Prop
Motor
battery voltage
Reduction
Speed at watts or amps

 
Thanks, Dan Pfeiffer


On 2021-01-11 11:42 am, Ryan Sweet wrote:

Thanks Peter. You LWL and displacement is likely similar to mine (Rawson 30) and these numbers are similar to mine except at the high end, where I see more of an exponential power curve the faster I go... 

On Jan 11, 2021, at 08:30, Peter Zephyr <Pcbeckett@gmail.com> wrote:

 

Actually the boat speed is around 5.6 knots when the regen starts.  My boat gets to that at around 8 knots on the wind.

 

 

Re: [electricboats] New prop 10KW motor

And motor type/reduction gear please...

 

On 2021-01-11 11:41 am, THOMAS VANDERMEULEN wrote:

Peter,
Great table of data ... thanks!
Please remind us what the displacement, LWL, and Max beam are of the Cat 30; and also provide prop specs (dia x pitch) and type (2, 3 blade, folding, feathering, etc).
Thank you!
[-tv]

Re: [electricboats] New prop 10KW motor

Thanks Peter. You LWL and displacement is likely similar to mine (Rawson 30) and these numbers are similar to mine except at the high end, where I see more of an exponential power curve the faster I go... 

On Jan 11, 2021, at 08:30, Peter Zephyr <Pcbeckett@gmail.com> wrote:



Actually the boat speed is around 5.6 knots when the regen starts.  My boat gets to that at around 8 knots on the wind.

 

Just FYI.  These are the figures I get when using the motor with no sails up. 

I did the readings in a fairly calm sea.  I have a Catalina 30 tall rig.

 

Catalina 30

Zephyr

boat speed data  8/31/18 - No sails up. Seas calm.

four, 215AH/batteries

Direction

Knots GPS

DC Amps

AC Amps

RPM

Volts

East

2.5

17

33

1110

48.9

East

3.2

31

44

1384

47.9

East

4.0

44

57

1584

47.9

East

4.6

78

90

1912

46.8

East

5.1

105

110

2108

45.8

East

5.2

106

108

2110

45.8

East

5.3

104

104

2100

45.9

West

2.5

7

18

845

48.2

West

3.2

11

22

1014

48.2

West

4.0

27

42

1379

47.9

West

4.6

38

54

1554

47.9

West

5.1

53

66

1727

47.0

West

5.2

68

78

1865

46.9

West

5.7

101

100

2103

45.8

Average

2.5

12

25.5

978

Average

3.2

21

33

1199

Average

4.0

35.5

49.5

1482

Average

4.6

58

72

1733

Average

5.1

79

88

1918

Average

5.2

87

93

1988

 

Rgds  Peter

From: electricboats@groups.io <electricboats@groups.io> On Behalf Of Carsten via groups.io
Sent: Monday, January 11, 2021 10:44 AM
To: electricboats@groups.io
Subject: Re: [electricboats] New prop 10KW motor

 

Hi, Peter

 

You mean that the boat speed should be more than 8 knots, not the wind speed, I guess ?

 

 

On Monday, 11 January 2021, 23:22:16 GMT+8, Peter Zephyr <pcbeckett@gmail.com> wrote:

 

 

Hi Carsten. 

  I don't really know how the regen works. All I can think of is by applying some power to the motor it somehow starts the prop to fee wheel and once it reaches a certain speed the amount of power it generates is greater than what it uses.   I had seen posts by others who have seen this happen and that is why I tried it. I usually get 1 to 2 amps when it generates and the wind has to be above 8 knots.  I have a Sevcon controller. 

 

Rgds Peter



On Jan 10, 2021, at 9:31 PM, Carsten via groups.io <Carstensemail=yahoo.com@groups.io> wrote:



It seems that some of you have actual experience with letting a fixed prop and motor "wheel" when under sail !

This is an option for daycruisers, but probably not for ocean cruising.

 

Any of you have some data (prop size and pitch, speed, Watt input) to make the prop spin for "no drag" ?

 

Peter Zephyr, you wrote : "in this situation the prop actually generates electricity and charges the battery".

If you send power to the prop, how can it generate power ?

Very interesting, so please enlighten us.

 

Carsten

 

 

On Monday, 11 January 2021, 01:34:35 GMT+8, Matt Foley <matt@sunlightconversions.com> wrote:

 

 

Michael, 

 

 With a traditional diesel engine, its kind of all or nothing. Typically you are either sailing or motoring. Motors sailing is an option but generally not an enjoyable one. 

 

With electric you will find yourself almost almost always motor sailing. Lets face it, the wind is usually not quite as strong we would like. If you want to make your prop "invisible" it doesn't take much power at all. If you want to add a little speed, help point higher and get you through lulls, it takes just a little more power. 

 

For those reasons, I recommend going with the most efficient prop you regardless of drag. This way you will have the more range when needed and still have the option of no drag by adding a few watts into the system. 

 

 

Matt Foley 

Sunlight Conversions

Perpetual Energy, LLC

201-914-0466

 

 

 

On Saturday, January 9, 2021, 09:04:25 PM EST, Carsten via groups.io <carstensemail=yahoo.com@groups.io> wrote:

 

 

Michael, consider a big folding or feathering prop, which will give you far less drag.

Then find the proper ratio for engine rpm and prop rpm.

 

A toothbelt solution will give you the opportunity to change the ratio.

 

 

On Sunday, 10 January 2021, 04:29:08 GMT+8, Michael Blackstock <mdblackstock@gmail.com> wrote:

 

 

Thanks for your responses, all. I think I'm just going to go with another stock 2 blade to reduce drag under sail. I plan on utilizing the motor very infrequently, so more speed under sail sounds good to me. 

There are so many resources for Catalina owners, but I thought I would check with you all first. 

I will definitely be chiming back in when I begin my motor and battery install!

Thanks

Michael Blackstock

Cell phone 503-913-8217