# planing a sailboat conversion



## Tarnacc (Feb 19, 2017)

Hello,


My first posting and let me thank you all for generating and maintaining such a wealth of information. I have been lurking for a little while now and reading up on old threads. I apologize in advance for the times I will ask questions that have already been asked and answered, I promise I try to search before I ask but sometimes I miss it or don't understand the answer. 


Ok so here is the project... 


My wife and I have a new to us sailboat. The boat is equipped with an inboard diesel which has not been run in at least ten years. Our plan was to pull it out and overhaul it before putting it back in and getting on with the sailing. I was inspired by reading the accounts of other people in our situation who made the conversion to electric and we feel this suits us pretty well. You can see the primary source of my inspiration and the basic model for what we are hoping to do here... http://www.sailinguma.com/electro-beke/#the-motor


I am a fairly handy guy and have tinkered to some degree or another with all of the systems involved but I am not properly schooled in any of them. I can weld but I am not what you would call a welder, I can wire things but I am not an electrician, I am not an engineer or machinist but I can make things and generally they work... You get the idea. Basically I can follow directions very well and can be creative in an area I am versed in but this is something I am not versed in and am hoping for some direction. 


What we hope to get out of this conversion... The boat is first and foremost a sailboat. The function of the auxiliary engine is to...


1) move the boat in calm waters and at slow speeds in and out of dock and anchorages. 


2) provide a little extra propulsion while under sail to help make a difficult point of sail. We are talking force equivalent to the existing 8 HP diesel running at maybe 1/4 throttle


3) Emergency full throttle we would really rather not hit that rock situations. 


4) backing down in full reverse to set the anchor. 






I want to share as much information as I can and I am not sure how to best organize it so I am just going to start listing pertinate information...






The boat has a displacement of around 7000 lbs.


The existing engine is a 8hp single cylinder diesel which from what I can determine maxes out at around 3000 rpm and the transmission uses a 2:1 reduction thus turning the propeller at around 1500 rpm. (take these numbers with a grain of salt. The engine is over 40 years old and was only produced for two years so information is somewhat scarce)


Max hull speed of the boat and the fastest emergency speed I could hope to attain is around 6 knots which by my calculations should require around 3.8kw worth of motor


We plan to use a solar array to charge the battery bank and hope to be able to harvest around 60 to 70 amp hours per day. This would be the basis for our "daily use and range". I am shooting for around 200 AH in the battery bank running either 36V or 48V. We will also have a house bank in 12V for running things such as cabin and navigation lights as well as provide the 12V for activating contactors/switches and so forth. 


We have thus far only been in the planning stages and trying to determine if the whole thing is feasible so have not begun in earnest to gather the components but we do have what we hope to be a suitable motor. The motor we obtained from a forklift repair shop and is a series wound 36/48V DC motor which used to drive a hydraulic pump. The part number is 324845


The motor...


part number 324845
36/48V
series wound
7.4kw (at 36V I think?)
around 2000 rpm (at 36V I think?)


This motor seems to be oversized for our application but not ridiculously so. The RPM seem to be right in line and it will fit perfectly in the planned location. Also, we already have it 


I am uncertain if it will be best to run in 36V or 48V. If run in 48V I think the RPM will be too high as I hope to run a direct drive. It may be possible to re-use the existing transmission from the old diesel but that would come with a 2:1 gear reduction. If the motor RPM get up to around 3000 under 48V then that should mesh very nicely. 


Transmission or direct drive?... If we use the existing transmission as opposed to direct drive then we can eliminate the need for the reverse switches and contactors which frankly confuses me. This would also take care of the running a brushed motor in reverse problem which I read about in another thread (thank you diyelectriccar forums!) Using the transmission however may create problems with fitting it all in and linking it together but I suspect that will be a mounting bracket and machining problem which I can work out with sufficient time, beer and head scratching. 


I want to keep the system as simple and robust as possible. We hope to one day down the road take this boat across some oceans so simple and robust are necessary but safety must always be foremost. Keep in mind that we never intend to use the motor to really take us anywhere in the way of a primary propulsion, the motor is there as an auxiliary and we figure that about an hours daily run time is a nice bench mark. Also, while safety and functionality are the most important, cost is of course a factor so we want to try to keep the costs down where possible.


I think perhaps that is enough for this first post as I know a great deal is yet to come. I suppose I will go ahead and ask my first two questions...


1) Is the motor we sources appropriate?


2) what are your suggestions for motor controller and where to source it?






Thank you all for reading and I appreciate your input.


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## Yabert (Feb 7, 2010)

Welcome Tarnacc
The link of your primary source of inspiration is basically a golf cart set-up mount inside a sailboat. It's an easy set-up.

About your motor. If it's a pump motor his rating is probably for a fraction of hour (example: 7,4 kw for 5 mins). That can be a problem if it not design to run for ''long time''.
Base on this, it's probably rated 7.4 kw for 12 mins/hour. But it can probabaly be good for 3 or 4 kw for an hour. 
The other potential problem is if your motor only have two terminals. To reverse a series wound motor, 4 terminals is need.
I like your idea of direct drive, but i'm not sure you actually have the right motor.

Don't hesitate to ask question, there is a ton of bright people here.


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## Tarnacc (Feb 19, 2017)

Thank you for the reply Yabert.

This speaks to one of the things that I need help with... Properly identifying this motor and its capabilities. You are correct, the motor has but two posts which is one of the things that leads me to believe that this is in fact a series motor. I believe the page you linked is in fact the same motor. 

I am aware of the difficulties in reversing such a motor, or at least I thought I was... I was operating under the belief that it could be done but required the correct controller in conjunction with a switch and reverse contactor. Am I incorrect in that or is it in fact impossible to reverse the thing?

The motor being rated for only a short time at the 7.4kw is actually not a problem as by my calculations the boat only requires around 3.5kw to sustain hull speed. It should also be noted that sustained hull speed for any extended length of time is not a requirement. If your estimate is correct then that would seem to put this motor right in the ballpark as far as sustained power output is concerned.

If we cannot run this motor in reverse then we could consider using the old transmission from the diesel which would allow us to shift reverse without affecting the motor rotation. 

Another question I have is that our motor has two small round terminal bushings with two blades per bushing. One is near the top of the case and the other is at the bottom near the brushes. I cannot determine with a meter where these things actually go. My theory is that the top two are leads for a temperature sensor located in the stator and the others are perhaps to monitor speed... Is this correct? 


https://www.dropbox.com/s/apfbmkmizhz4lff/0215171203a.jpg?dl=0

I had found the link you posted in my own research but looking at it again, I am now not sure that is in fact the same motor. Will you please examine the link above to picture of my motor?

Thank you again for your help.


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## Duncan (Dec 8, 2008)

Hi Tarnac
For your application I would get myself a drive motor rather than the pump motor - 
For two reasons
The driveshaft on most pump motors ends in a short female spline - it's difficult to make up anything to to convert this to something that can couple to your prop shaft 

pump motors tend to be unidirectional - and if you can't get to the field coils separate to the armature you can't reverse the direction

You could keep the gearbox - but it's a big heavy oily thing you really don't need!

For what you are doing don't mess about "advancing the brushes" - that is only if you are overvolting/overspeeding the motor

As you are going to stick to 36/48v then you will be able to use the controller from the forklift

BUT - you may not need a controller! -you may be able to simply use a contactor to drive the motor
A switch - Forwards or Backwards - the motor will simply spin the prop until the motor torque equals the water load on the prop
As revs rise the motor torque will drop and the water load will increase

If you were "sailing" the load would go down and the motor revs would rise so that it was still helping you along


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## Tarnacc (Feb 19, 2017)

Hello Duncan and thank you for your reply.

with regards to the shaft, it actually ends with a solid shaft with only a simple... key? I think that is what its called. The shaft is 19mm in diameter. 

All other things being equal I would prefer to ditch the transmission but it does offer some advantages. It provides a convenient way to receive the thrust from the propeller. It allows us to keep the motor turning in one direction which I have read is a good thing as reversing can damage the brushes or commutator. It provides a simple 2:1 gear reduction which could come in handy as it seems that most DC motors have much higher RPM then I want at the propeller. And perhaps most importantly it provides a reverse gear without using any contactors or switches. And it seems is in fact the only way I could get reverse out of this motor anyway.

You lost me with advancing the brushes... I don't know what that means.

As to the controller from the forklift, I don't have it. We only purchased the motor by itself.

Your no controller concept is interesting and I think I am following you. If I understand you correctly this would mean that it is a simple on and off arrangement. Are you suggesting that at some point the torque of the motor and the load produced from the water would equal out and the RPM would top out naturally and this would prevent the motor from spinning itself out of control? I don't suppose there is a way to predict what that RPM might be?

Thanks for your input.


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## Duncan (Dec 8, 2008)

Hi
The DC motors used in Forklift traction are used nearly as much backwards as forwards so they have "neutral" brush timing (the position of the brushes on the com) - when we increase the rpm and voltage we advance the brushes - that makes them work better at speed - but a lot worse in reverse

We normally test a 36/48v motor by spinning it with no load AND A REDUCED VOLTAGE

If you apply 48v and no load it will overspeed

But if you try 12v - it will spin away nicely

You could assemble the motor to the gearbox and prop (in the water) and just give it 12v - see what speed it reaches
Then try 24v
Then 36v
Then 48v

The controller running at 100% is the equivalent of just connecting the battery to the motor

That would also give you a way of getting less power if you needed it
The only trouble is that you don't want to discharge part of your battery pack so that when you charge you overcharge the other batteries

You could handle that if you were careful - use battery A - then B ......


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## Tarnacc (Feb 19, 2017)

Ok I am following you and I understand. Thank you for explaining about advancing the brushes. 

I understand the concept but I really think I want a controller. A great deal of the time spent using the motor will be at low speeds in possibly tight quarters which requires finer control. 

Earlier on we saw this link http://yabe.chudov.com/GE-FORKLIFT-...B182-7-4kW-36-48v-2121-RPM-5953/ebayhist.html which I assumed to be the same motor. Here is a picture of the actual motor sitting in our garage https://www.dropbox.com/s/apfbmkmizhz4lff/0215171203a.jpg?dl=0

Can you tell me if this is in fact the same motor and are the RPM values accurate? Does the 5953 RPM value represent the RPM in 48V?


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## electro wrks (Mar 5, 2012)

There are a couple of issues to think about using an open or not completely sealed brushed motor in a marine application. Generally the Coast Guard (in the US, it may be the same elsewhere) requires electrical equipment, like motors and switches, to meet an "ignition protected" standard. This usually involves extra gaskets and seals to reduce the chances of electrical equipment igniting explosive or flammable fumes that might collect in the boat. Boat's bilges being a good place for heavier than air fumes, like from gasoline or propane, to collect. The "ignition protected" standard is similar to, but not as strict, as the NEMA and UL "explosion proof" standard. Check the label on the pump motor below.

You might say "so what?" and, initially, I didn't think much about it. Then, there were some high profile boat explosions, involving deaths, from repair shops installing non-ignition protected, automotive type parts in boats. I think it was starters or alternators. We're talking huge lawsuits and jail time. Something to think about when dealing with the CG and insurance people. You may be able to seal the motor away from fume sources by using CG approved bulkhead and ventilation requirements.

Also, low in the boat, close to the bilges, can be a pretty corrosive environment. You might talk to an electric motor shop about encapsulating the motor windings for extra protection. Usually an special epoxy is used. This may reduce the ability of the motor to shed heat-so extra cooling may be needed. Brush holder parts, especially springs, should be replaced with corrosion resistant parts if possible or heavily painted or plated.

I see the Sailinguma folks didn't do much to address these issues. Let's hope they don't regret it.


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## Tarnacc (Feb 19, 2017)

Good things to think about electro. This did not occur to me until yesterday and like you, I did not think too much about it. I do not have any propane or gasoline or fuel of any kind on the boat so I figured no big deal. After your post I thought about it again and realized that I did have gasoline in the form of the outboard dingy engine. The engine itself is not a problem as it will be stored above deck on the stern rail but the reserve fuel however is an issue. 


I spent some time today looking over the coast guard and the ABYC standards and regulations on the subject. More study is required but I think I can pretty easily comply with some common sense storage of the reserve fuel. That does not address the corrosion issues you brought up though. 


There is an electric motor place near me which is on my short list of people to talk to (actually until today I did know they existed) and I plan to go to them for parts and whatever work needs to be done on the motor so I will see what kind of advice they have for me specific to this motor. 


You are right about the UMA crew and their installation as well. To make matters worse, they use propane and store their gasoline outboard in the lazzarette which shares the same space as their motor... 


Thank you for your observations.


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## Yabert (Feb 7, 2010)

Tarnacc said:


> I understand the concept but I really think I want a controller.


I think too. It's the kind of 200-300$ well spended for your situation.



> Can you tell me if this is in fact the same motor and are the RPM values accurate? Does the 5953 RPM value represent the RPM in 48V


This kind of motor can spin from 1000 to more than 6000 rpm at the same 48v. Everything depend of the load. In the case of your motor his rating is 2121 rpm under load at 36v (I think base on this: 36v x 280A x 0.735 (efficiency) = 7,4 kw).
But anyhow, I suggest you to find another motor with 4 terminals to symplify the reverse.


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## nucleus (May 18, 2012)

*Brushed Motor in a Marine Environment?*

I think that using a brushed motor in a marine environment is a bad idea. I grew up on the water, and the way salt mist gets everywhere, you run the risk of leaving your boat sit for a few days and having your commutator oxidize so much that it won't run.

I would go AC. You can use a Curtis controller with an AC-9, you will have power to spare for reef emergencies, no sparks, and no need to cobble a controller together.

Whoever said you won't need a controller hasn't docked sailboats before.

Here is the power graph for the AC-9


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## cpcanoesailor (Dec 1, 2016)

Maybe an ICE replacement kit is an easy way to go?
I've heard good things about Thunderstruck kits, like
http://www.thunderstruck-ev.com/sevcon-brushless-sailboat-kit-8.5kw.html
Several members at the Yahoo Electric Boats forum have used them (not to diminish the wealth of info here).


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## Tarnacc (Feb 19, 2017)

I know I could make the series pump motor I have work but after some of the comments here and after more of my own research I am now leaning towards something like this 
http://www.electricmotorsport.com/e...201-pmac-motor-24-72v-6-hp-cont-19-hp-pk.html

Fits the power requirements near perfectly, is brushless and should hopefully give me a longer more hassle free life. The over all investment will be more but i think it will be worth it. 

Sent from my VS986 using Tapatalk


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## galderdi (Nov 17, 2015)

Ditch the sails, replace them with a solar array and a wind turbine driving charge into a nice big battery bank. Then run a nice big pair of AC motors to power you along at 40 or 50 knots.......Can you tell I'm a rev head


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## Tarnacc (Feb 19, 2017)

Ok, next line of questioning... I am looking at this motor 
http://www.electricmotorsport.com/e...201-pmac-motor-24-72v-6-hp-cont-19-hp-pk.html

And so far I have found these two controllers which seem to make sense. 
http://www.electricmotorsport.com/ev-parts/controllers/sevcon-gen4-36-48-275.html

And this one. 
http://kellycontroller.com/kls7230s24v-72v300asinusoidal-brushless-motor-controller-p-1343.html

Are both of these controllers compatible with the motor I linked? I was going through the user manual for the kelly and it talked about hall sensors, what are hall sensors and would the gen4 require them as well? Would there be programming issues with either of these controllers and would I be able to set them up myself without some kind of expensive proprietary software? 

The kelly controller looks to me like it would work perfectly and is less the half the cost of the sevcon. Also the kelly claims that I can program it with an Android app but I am not sure I believe that as it seems like a too good to be true kind of thing. I would rather not throw money at the gen4 if there is no need so I would appreciate your opinions. 

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