Friday, October 31, 2014

[Electric Boats] Re:Trolling motor for small DIY bow thruster?

 

I won't be sailing. The entire boat will eventually be shaded by a hard canopy with solar panels on top and all sail rigging is coming down. I considered the trolling motor rigged as you suggest but it will want more support, and be ugly and awkward. I thought about a motor well but that would mean giving up my vee berth. I think I want it in a tunnel, or not at all.

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Re: [Electric Boats] Electric trimaran conversion

 

I agree with Jason. 48v works great for boats under 35' but 72 to 144 would be better for your boat. Don't go under 10kw motor. 5kw is a bit over 6hp. Pretty marginal for your size boat.

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Re: [Electric Boats] Re: Electric Ericson 27 Long Beach California

 

Electricmotorsports for the 4201 motor. I got two cause they were cheap. Kelly for the controler, contactor and fuse, some crappy meters that I tossed, a charger that is actually too small, and a few other doodads in a kit. Gearbox I don't remember but it is a Baldor. McMaster-Carr for the steel, jumper shaft, shaft couplings and other hardware. Radio Shack for the parts for the control box. Sams Club for my batteries. Ebay for shunt and ammeter, voltmeter, and other stuff. Home Depot for bolts, wood, etc.

You already have a 12v house bank, right? Do you have problems with acid sloshing out? I am guessing not. Ditto with gassing. Yes hydrogen is explosive and yes it destroyed the Hindenburg but normal charging and discharging only release small amounts of it, and since it is lighter than air it simply floats away if not confined. Proper precautions (do not be a smoker, for instance) avoid pretty much all accident potential. Your battery box needs to be strong enough to keep your batts from shifting but still allow minor swelling, and needs to be able to keep water and debris off of them. 48v at 220ah or more is a lot of juice, and a dropped wrench or screwdriver should not be allowed to fall across battery terminals. Sucks when that happens. Also the shock hazard is considerable even at 48v. You can weld with only 36v. I have done it.

Figure on a minimum of a years serious research before whipping out the credit cards. 2 years even better.

Remember you can't have a brushed motor if you have gasoline or propane accessories aboard.

48v is a good voltage for boats under 35 feet. Over 40 you should be looking at 72 to 144v. There are different electrical standards to follow over 50v but if you go 72 you may as well go higher. Higher voltage means less current, lower line losses, smaller cable. 48v means simpler installation and more chargers, converters, etc available and for lower prices.

Stick with the usual setup of Kelly or Sevcon controller, Mars/Motenergy motor, and a 1.5:1 to 3:1 reduction gear to start, and you won't be far off for a small sailboat.

A vendor package gives you the benefit of proper engineering and testing. Only go the full DIY route if you are a pretty good tinkerer and shade tree engineer and want the challenge/fun.

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[Electric Boats] Re:Trolling motor for small DIY bow thruster?

 

On your boat I would be more concerned about the drag associated with a bow thruster than anything else, especially under sail.

Perhaps add a small bow sprit (cutter rigs are great anyway!).  Just rig the trolling motor under the bow sprit on some kind of rig like a roller furler uses so you can retract it when not needed.  ;-)  Then just use the trolling motor without modification except for mounting.

John

--
Flatwater Electronics
www.flatwaterfarm.com
"Neurosurgery for computer looms."

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Re: [Electric Boats] Electric trimaran conversion

 

Hi Phil,

You forgot to mention the displacement of the boat. 
Also, when reaching under sail in say 15kts of wind,what kind of speeds do you see with your existing setup?

I suspect that you may want to consider a higher voltage system, if only to keep currents down to manageable levels. A light displacement trimaran is still going to displace in the neighbourhood of 10 tonnes.

You should be looking at a 10-12kw system running at 72V which would keep amps down around 160A max. 

Look for posts in the archives about "Current Sunshine", a 37' trimaran who's owner (used to?) post here. 

Sounds like a fun project of you go ahead with it. 

Cheers,

/Jason

On Oct 20, 2014, at 11:42, Phil Aylsworth paylsworth@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

 

Hi all,
I'm looking for what some of you have already sent; real world results and accounts of the conversion process.
First I've got to see if converting to electric drive is a good idea of a bad one. Considering that the motor part is just a way to transfer fuel/energy into propeller force, it's the energy or fuel I need to focus on. And the cost to use diesel or electric. The Perkins engine is getting old in years but still has only 600hrs on it. There's resale value here if I convert and can sell the engine. But if not there's still life in it.

The boat is a 49' trimaran, driven by a Perkins 4.108. Perkins rated power curve shows about 47hp at 3,000 rpms but I never get up that high. At 2200-2500 rpm, good sea (1-3' wind waves, 1-4' swells) and up to 10knots wind I can make 8knots easy. For a displacement hull my hull speed should be 8.9knots, for a semi-displacement it's 16knots. I believe a trimaran falls in between, and the drawn (from designer) hull speed is 16. These are all theoretical and I'm happy motoring at 8. I've got lots of room for batteries or diesel so space isn't an issue, weight is.

Cruising is on the Pacific coast, mostly shoreline but in the coming years there will be several crossings to HI and South Pacific islands. I'm a sailor so most of this will be under sail. There are 500W of solar and a large wind generator available for replenishing battery banks. And the power regen may be more effective on an electric drive if I'm sailing at higher speeds than a full displacement monohull. This again is theoretical. The prop is a big 18" three-blade at a pitch of about 12, fixed.

The Perkins power curves list a propeller law power loss of 2.8. Figuring this; the 2600rpm hp available to the prop falls to 15hp. The torque at 2600rpm is 75 ft/lb. This is information from the Perkins mfr for this exact engine and roughly the same year. My gearbox has about a 2.1:1 conversion so I am figuring that a 2:1 belt reduction will serve well as both a way to safely couple engine to shaft and to increase hp and torque with higher electric motor revs. (not sure this is accurate and if not I want to eliminate the reduction).

Now the energy. The plan is to have a 300A/hr bank at 48V, with a portable gas generator (gas will be onboard for the dinghy outboard anyway). The generator will be used off the boat too, for construction work or whatever else. It will be sized to wire directly into the motor controller, giving enough motor power for a 60 or 70% throttle in case of prolonged motoring. There are 48V generators so this is the chosen voltage. Again, just theoretical but it sounds correct.
I don't expect solar and wind to provide all the electricity I'll need for motoring, though they do provide more than enough for living off the grid for the rest of the boat.

Any suggestions or comments on this would be greatly appreciated.

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Posted by: Jason Taylor <jt.yahoo@jtaylor.ca>
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Re: [Electric Boats] Re: Amphicar conversion

 

http://www.ruckmarine.com/torqeedo-electric-outboards/

Best,

Nick Deuyour
CityYachts & Gashouse Cove
10 Marina Blvd SF CA 94123
(415) 595- 5373

On Oct 21, 2014, at 6:18 AM, king_of_neworleans <no_reply@yahoogroups.com> wrote:

 

10hp is nominally 7.4kw. Roughly 308a at 24v. That's an awful lot of current, and line losses will be significant at that power level. That's if you can find a motor and controller combination that will work at 24v. I urge you to not even consider less than 48v. Very likely you will want a reduction gear of some sort. A 10kw ME0913 at 72v with a 500a controller and a Baldor 2:1 enclosed gearbox would do the trick. You should develop your desired power level from such a setup.

You do understand that batteries will be a huge factor in range and in conversion costs, right? Not to mention weight. Maybe with a big enough 48v alternator on your engine you can get by with a reasonably small battery bank and running the engine to turn the electric motor at low speed and extend your range. 100 amps at 48v is nearly 5kw, about 6hp if you have an efficient setup.

IMHO, you need to completely forget about 24 volts.

You can't power the prop from your engine?

Another option would be to use electric for both land and water propulsion, either standalone with the addition of a small diesel generator and charging from home/shore power, or a series hybrid setup where the engine and electric motor are both coupled to the drive shaft. When running on the engine, the motor can generate power and charge the batteries. When running on the motor, the engine is decoupled by taking its transmission out of gear. The motor could also be used as the engine starter.

I have a feeling that this will be a complicated project. Maybe it would be good to first build a small electric boat and get some hands on with electric propulsion on a simpler platform And Lower Power level first.

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Thursday, October 23, 2014

Re: [Electric Boats] Re: Electric Ericson 27 Long Beach California

 

Hi King_of_neworleans,

Your low cost conversion is impressive, the quotes I have received from vendors have been "considerably" more than your total outlay,even considering their DIY options.  Yes, there is a certain peace of mind when considering a turn key system, and I have not yet established my budget/peace of mind ratio yet.  Where did you purchase your components (motor, gearbox, controller, charger)?  I have found various EV vendors online with parts you can mix and match (if you know what you are doing), which I don't.  Of course those parts are not necessarily intended for a marine application, mostly designed for two and four wheel projects.  I have read quite a bit about flooded batteries on sailboats and the "complexities", how are you managing the "acid" spills (if any) when heeling.  and what about the Hydrogen off gassing?  Lots of questions I know, Thanks for any additional information.

-Scott

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Re: [Electric Boats] Re: Electric Ericson 27 Long Beach California

 

Hi Eric,


Thanks for the information and the link.  I believe I will go with the 5KW  version, all the quotes from vendors suggest that this is the appropriate choice as well.  I can understand Johnathan's choice to go 10KW, but since I don't intend to upgrade in boat size anytime in the near future... as if I could foresee the future! :)  Anyway, thanks again for the information.

-Scott

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Tuesday, October 21, 2014

[Electric Boats] Trolling motor for small DIY bow thruster?

 

I have never torn apart a trolling motor and I was wondering how they manage to stay water tight indefinitely at the prop shaft. Since I am heavily modifying the boat anyway, I figured a bow thruster tunnel would be the perfect Frankenstein-esque touch and a trolling motor would be the cheap and simple thing to stick in there. As always on my $2000 boat, I will be going cheap rather than high performance. Any thoughts?

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[Electric Boats] Re: Amphicar conversion

 

10hp is nominally 7.4kw. Roughly 308a at 24v. That's an awful lot of current, and line losses will be significant at that power level. That's if you can find a motor and controller combination that will work at 24v. I urge you to not even consider less than 48v. Very likely you will want a reduction gear of some sort. A 10kw ME0913 at 72v with a 500a controller and a Baldor 2:1 enclosed gearbox would do the trick. You should develop your desired power level from such a setup.

You do understand that batteries will be a huge factor in range and in conversion costs, right? Not to mention weight. Maybe with a big enough 48v alternator on your engine you can get by with a reasonably small battery bank and running the engine to turn the electric motor at low speed and extend your range. 100 amps at 48v is nearly 5kw, about 6hp if you have an efficient setup.

IMHO, you need to completely forget about 24 volts.

You can't power the prop from your engine?

Another option would be to use electric for both land and water propulsion, either standalone with the addition of a small diesel generator and charging from home/shore power, or a series hybrid setup where the engine and electric motor are both coupled to the drive shaft. When running on the engine, the motor can generate power and charge the batteries. When running on the motor, the engine is decoupled by taking its transmission out of gear. The motor could also be used as the engine starter.

I have a feeling that this will be a complicated project. Maybe it would be good to first build a small electric boat and get some hands on with electric propulsion on a simpler platform And Lower Power level first.

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Monday, October 20, 2014

[Electric Boats] Re: Fugu electric conversion performance

 

king_of_neworleans,


Great summations.  For the drawback of range, there is so much better about e-propulsion!

Mark Stafford

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[Electric Boats] A Motor performance comparison

 

What would be the downside of using a 72V motor at 48V, and particularly when predominately run at lower rpm?

I just found the data on a Montenergy 4201 rated at 85A @72V, and it's torque at the lower end looks good.  But wondering how well it will do at low A & low rpm.

John
--
Flatwater Electronics
www.flatwaterfarm.com
"Neurosurgery for computer looms."

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[Electric Boats] Electric trimaran conversion

 

Hi all,
I'm looking for what some of you have already sent; real world results and accounts of the conversion process.
First I've got to see if converting to electric drive is a good idea of a bad one. Considering that the motor part is just a way to transfer fuel/energy into propeller force, it's the energy or fuel I need to focus on. And the cost to use diesel or electric. The Perkins engine is getting old in years but still has only 600hrs on it. There's resale value here if I convert and can sell the engine. But if not there's still life in it.

The boat is a 49' trimaran, driven by a Perkins 4.108. Perkins rated power curve shows about 47hp at 3,000 rpms but I never get up that high. At 2200-2500 rpm, good sea (1-3' wind waves, 1-4' swells) and up to 10knots wind I can make 8knots easy. For a displacement hull my hull speed should be 8.9knots, for a semi-displacement it's 16knots. I believe a trimaran falls in between, and the drawn (from designer) hull speed is 16. These are all theoretical and I'm happy motoring at 8. I've got lots of room for batteries or diesel so space isn't an issue, weight is.

Cruising is on the Pacific coast, mostly shoreline but in the coming years there will be several crossings to HI and South Pacific islands. I'm a sailor so most of this will be under sail. There are 500W of solar and a large wind generator available for replenishing battery banks. And the power regen may be more effective on an electric drive if I'm sailing at higher speeds than a full displacement monohull. This again is theoretical. The prop is a big 18" three-blade at a pitch of about 12, fixed.

The Perkins power curves list a propeller law power loss of 2.8. Figuring this; the 2600rpm hp available to the prop falls to 15hp. The torque at 2600rpm is 75 ft/lb. This is information from the Perkins mfr for this exact engine and roughly the same year. My gearbox has about a 2.1:1 conversion so I am figuring that a 2:1 belt reduction will serve well as both a way to safely couple engine to shaft and to increase hp and torque with higher electric motor revs. (not sure this is accurate and if not I want to eliminate the reduction).

Now the energy. The plan is to have a 300A/hr bank at 48V, with a portable gas generator (gas will be onboard for the dinghy outboard anyway). The generator will be used off the boat too, for construction work or whatever else. It will be sized to wire directly into the motor controller, giving enough motor power for a 60 or 70% throttle in case of prolonged motoring. There are 48V generators so this is the chosen voltage. Again, just theoretical but it sounds correct.
I don't expect solar and wind to provide all the electricity I'll need for motoring, though they do provide more than enough for living off the grid for the rest of the boat.

Any suggestions or comments on this would be greatly appreciated.

__._,_.___
Posted by: Phil Aylsworth <paylsworth@yahoo.com>
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Re: [Electric Boats] Hunter Cherubini 37 conversion

 


Hi Curt,

I also have a Hunter Cherubini 37, and am also talking with Electric Yacht.  In fact after exploring all the options and various levels of DIY I have decided they are the way to go.  My boat is in the US Virgin Islands, and my cruising will be coastal and offshore.  Based on that and the size/displacement they have recommended a 2x10KW setup, which they call a 20KW installation.  I missed my window to get it installed this summer, but am shooting now for next Spring.  I am very interested in how you get on.

Cheers,

j

On 10/20/2014 09:55 AM, Sally Reuther smreuther@gmail.com [electricboats] wrote:
 
Curt,

Much depends on what top motoring speed you want to achieve. The faster you want to go the more kW you will need. Also, what are you doing with your boat? Are you mainly day sailing, or are you cruising? Also, where are you sailing? Conditions are always a factor in sizing the system to fit your boat and sailing needs. 

A 30', 18,000lb boat on a lake or protected bay is going to be different than a boat that is cruising coastal areas, or further into open water. Also, make sure you know what the continuous kW rating is on the systems you are looking at. Peak ratings may be listed, but continuous is what is important. 

Your boat's calculated hull speed is 7.3. A boat under sail can go past it's hull speed, but not under power unless you have a favorable current or wind helping you along. If you want to push your boat at 7 knots under power you are going to be looking at higher a kW system - 16kW or more. (That is continuous rated) If you are happy motoring at just over 6 knots, then something around 10kW to 12kW (continuous) will work. 

Look at all of your options and then you will be in a better situation to decide if electric is the best plan for you. Sometimes cheaper is not always better. 

Sally Reuther
Annapolis Hybrid Marine

On Sat, Oct 11, 2014 at 12:43 PM, e.nichols@cox.net [electricboats] <electricboats@yahoogroups.com> wrote:
 

Good Morning, 


Thanks for the folks that started this. My Hunter has a Volvo D1 30 that I am at wits end with. It generated 27 HP before its death. 


I am contemplating a electric conversion.. My ladies displacement is 17,800 with thhe motor in, and none of my junk. 


She is a fairly easily driven hull that will do 8 knots under jib alone. 


I was looking at the Thunderstruck 12.5 KW system and the 15 KW system from electric yacht. 


Any advice on this would be appreciated. 


Regards, 


Curt 



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