# boat engine controller?



## bobsmith (Sep 3, 2013)

*bobsmith*

This is my first post and i sure hope someone out there can help me. I have two clark au2542 type engines from a lift truck. They are 9 magnet if my info is right. I really know nothing about them or where to go for parts-controller etc. I am currently changing a 37' cabin cruiser to run on electric, and will post pics. And progress as i go along. I also need to know if they are reversable. Thanks for any help available.


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## major (Apr 4, 2008)

*Re: bobsmith*



bobsmith said:


> This is my first post and i sure hope someone out there can help me. I have two clark au2542 type engines from a lift truck. They are 9 magnet if my info is right. I really know nothing about them or where to go for parts-controller etc. I am currently changing a 37' cabin cruiser to run on electric, and will post pics. And progress as i go along. I also need to know if they are reversable. Thanks for any help available.


Hi bob,

The AU2542 number sounds like a UL file number and tells us nothing. The 9 magnet doesn't make any sense. So I guess you need to post some photos, measurements (size and weight) and nameplate data. The controller choice depends a lot on the application; battery, power requirements, duty cycle, etc.

major


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## bobsmith (Sep 3, 2013)

Help! Being a novice in the ev builder circuit I need some help in the controller dept. I am currently planning to install 2 clark forklift motors in my cabin cruiser and to charge them with solar panels; also using 2 sets of batteries for each motor, so that one set is always charging. My question is this; do I need to use controllers in this situation or can I just use poitenometers(don't think I spelled that right). I am running the motors direct as they reversing so I need no transmission. I welcome any response as this is my first ev conversion. Thank You, bobsmith


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## onegreenev (May 18, 2012)

You will want a controller. The potentiometer is used for throttle control to the controller. What voltage are you going to use for your pack's. 96 volts? 120 volts? 144 volts? 156 volts ? 192 volts or higher? For a boat you might consider a Soliton 1. It is well sealed and water cooled and can give quite the power if needed or wanted. 

Do you have pictures of your setup? Boat?


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## major (Apr 4, 2008)

bobsmith said:


> Help! Being a novice in the ev builder circuit I need some help in the controller dept. I am currently planning to install 2 clark forklift motors in my cabin cruiser and to charge them with solar panels; also using 2 sets of batteries for each motor, so that one set is always charging. My question is this; do I need to use controllers in this situation or can I just use poitenometers(don't think I spelled that right). I am running the motors direct as they reversing so I need no transmission. I welcome any response as this is my first ev conversion.


You need motor controllers. Ref: http://www.diyelectriccar.com/forums/showpost.php?p=204460&postcount=3

Also, your plan sounds flawed. You would be wise to start a thread describing your plan and get feedback. Two sets of batteries on-board so one can charge while using the other is a waste of resources.


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## bobsmith (Sep 3, 2013)

*Ev boat----what the h- is going on*

I HAVE TRIED TO POST THIS TREAD FOUR TIMES AND EVERY TIME IT SAYS I AM NOT LOGGED IN EVEN THOUGH I AM. AM I DOING SOMETHING WRONG? HELP! GOING TO TRY ONCE MORE! I AM DOING AN EV CONVERSION WITH A 37 FOOT CABIN CRUISER. I ALREADY HAVE TWO CLARK DC MOTORS WHICH ARE REVERSING SO I HOPE TO DO THIS WITHOUT TRANNYS WHHICH I HAVE FROM OLD SETUP. I ALSO PLAN TO CHARGE BATTERIES WITH SOLAR PANELS. I NEED CONTROLLERS AND ADVICE ON BATTERIES ETC. FOR THE CONVERSION. GOOD OR BAD SEND ME SOME INPUT. THANK YOU, bobsmith


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## major (Apr 4, 2008)

*Re: Ev boat----what the h- is going on*



bobsmith said:


> I HAVE TRIED TO POST THIS TREAD FOUR TIMES AND EVERY TIME IT SAYS I AM NOT LOGGED IN EVEN THOUGH I AM. AM I DOING SOMETHING WRONG? HELP! GOING TO TRY ONCE MORE! I AM DOING AN EV CONVERSION WITH A 37 FOOT CABIN CRUISER. I ALREADY HAVE TWO CLARK DC MOTORS WHICH ARE REVERSING SO I HOPE TO DO THIS WITHOUT TRANNYS WHHICH I HAVE FROM OLD SETUP. I ALSO PLAN TO CHARGE BATTERIES WITH SOLAR PANELS. I NEED CONTROLLERS AND ADVICE ON BATTERIES ETC. FOR THE CONVERSION. GOOD OR BAD SEND ME SOME INPUT. THANK YOU, bobsmith


I don't know but I can find them no problem:



bobsmith said:


> This is my first post and i sure hope someone out there can help me. I have two clark au2542 type engines from a lift truck. They are 9 magnet if my info is right. I really know nothing about them or where to go for parts-controller etc. I am currently changing a 37' cabin cruiser to run on electric, and will post pics. And progress as i go along. I also need to know if they are reversable. Thanks for any help available.





major said:


> Hi bob,
> 
> The AU2542 number sounds like a UL file number and tells us nothing. The 9 magnet doesn't make any sense. So I guess you need to post some photos, measurements (size and weight) and nameplate data. The controller choice depends a lot on the application; battery, power requirements, duty cycle, etc.
> 
> major


http://www.diyelectriccar.com/forums/showthread.php?t=88902



bobsmith said:


> Help! Being a novice in the ev builder circuit I need some help in the controller dept. I am currently planning to install 2 clark forklift motors in my cabin cruiser and to charge them with solar panels; also using 2 sets of batteries for each motor, so that one set is always charging. My question is this; do I need to use controllers in this situation or can I just use poitenometers(don't think I spelled that right). I am running the motors direct as they reversing so I need no transmission. I welcome any response as this is my first ev conversion. Thank You, bobsmith





onegreenev said:


> You will want a controller. The potentiometer is used for throttle control to the controller. What voltage are you going to use for your pack's. 96 volts? 120 volts? 144 volts? 156 volts ? 192 volts or higher? For a boat you might consider a Soliton 1. It is well sealed and water cooled and can give quite the power if needed or wanted.
> 
> Do you have pictures of your setup? Boat?





major said:


> You need motor controllers. Ref: http://www.diyelectriccar.com/forums/showpost.php?p=204460&postcount=3
> 
> Also, your plan sounds flawed. You would be wise to start a thread describing your plan and get feedback. Two sets of batteries on-board so one can charge while using the other is a waste of resources.


http://www.diyelectriccar.com/forums/showthread.php?t=88866


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## major (Apr 4, 2008)

*Re: Ev boat----what the h- is going on*

Also, when you log in, check _remember me_


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## alvin (Jul 26, 2008)

*Re: Ev boat----what the h- is going on*

The controllers can be from one of the suppliers listed on the right side of the page. You will need to know more about the motors. Major mentioned in one of your other threads to post pics. 

LiFePo cells seem to be best. I use Winston brand but any of the other brands are probably good too.

My controller is the OpenRevolt that you put together yourself. Very inexpensive. One controller for each motor would make it easier to maneuver around the dock.

The reversing would probably need reversing contactors.

Good Luck. And post some pics.

Alvin


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## ga2500ev (Apr 20, 2008)

bobsmith said:


> Help! Being a novice in the ev builder circuit I need some help in the controller dept. I am currently planning to install 2 clark forklift motors in my cabin cruiser and to charge them with solar panels; also using 2 sets of batteries for each motor, so that one set is always charging. My question is this; do I need to use controllers in this situation or can I just use poitenometers(don't think I spelled that right). I am running the motors direct as they reversing so I need no transmission. I welcome any response as this is my first ev conversion. Thank You, bobsmith


Just to echo Major, it makes little sense to have batteries that you are not actually using. By using one large pack, you can funnel the solar energy directly to the motors when they are running, and to the battery pack when they are not. Your battery pack size should only be constrained by size, weight, and cost constraints. Put in the largest pack you can afford and fits into the boat.

As for the controller. The only situation where you would not need one at all is if the motor always runs full throttle. A motor controller gives you the ability to control the speed of the motor, which is directly coupled to the voltage across it. Full voltage gives full speed. No voltage gives no speed. If that is good enough, then all you need is a switch.

But it's likely that you need to throttle the motor so that it goes a speed inbetween full speed and no speed. The potentiometer (or the power version called a rheostat) would do this by putting a variable resistance across the pack. So part of the energy would go the motor, while the rest would be burned up in the rheostat in heat. Heat is terrible for efficiency as the energy is just wasted instead of going into the motor.

So imagine if you only had a full on/full off switch for your motor. Clearly if you left the switch on, you'd go full speed. And conversely if you left it off, you'd not move. But how can you use such a system to move the boat slowly.
You'd do it by pulsing the switch. You'd turn it on for a short time, then turn it off. The boat would move forward a bit, but not at full speed. If you kept flicking the switch on and off, the boat would move, but at a slower speed than full speed because the switch isn't on all the time.

But it gets even better. A motor acts as an inductor, which is a coil of wire. It has a property where if you put energy into it by inducing a current, that even when you turn off the switch, it doesn't immediately turn off. It can continue to use the energy put into it even though no new energy is being introduced. In short it spins up slower than full speed, and it spins down slower than full off too.

So if you pulse the switch fast enough, instead of a jerky motion where the motor is full on or full off, you get a smooth motion at a slower speed than full on.

The best thing about it is that the energy is completely put into the motor instead of being burnt up as heat. So it is very efficient in terms of using most of the batteries energy for power.

This method of motor control is called Pulse Width Modulation, or PWM.
So a motor controller is a device that does the operation above for you. It uses a set of transistors as the switch, and a microcontroller to translate your throttle information to the length of time the switch should be on. Controllers switch anywhere from 1000 times a second to 25000 times a second. Keeps you hand from getting tired 

There are some other items that are required to build a controller, but this is the basic idea.

Hope this helps,

ga2500ev


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## Woodsmith (Jun 5, 2008)

*Re: Ev boat----what the h- is going on*



bobsmith said:


> I HAVE TRIED TO POST THIS TREAD FOUR TIMES AND EVERY TIME IT SAYS I AM NOT LOGGED IN EVEN THOUGH I AM. AM I DOING SOMETHING WRONG? HELP! GOING TO TRY ONCE MORE! I AM DOING AN EV CONVERSION WITH A 37 FOOT CABIN CRUISER. I ALREADY HAVE TWO CLARK DC MOTORS WHICH ARE REVERSING SO I HOPE TO DO THIS WITHOUT TRANNYS WHHICH I HAVE FROM OLD SETUP. I ALSO PLAN TO CHARGE BATTERIES WITH SOLAR PANELS. I NEED CONTROLLERS AND ADVICE ON BATTERIES ETC. FOR THE CONVERSION. GOOD OR BAD SEND ME SOME INPUT. THANK YOU, bobsmith


I have merged all your threads into one so it will be easier to keep track of the information and advice.

Hopefully you will be able to see your threads and post effectively. As has been said, try the 'Remember Me' check box, or (as I have to do when I am non Mobile Broadband) press F5 to refresh the screen after logging in and between actions.


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## bobsmith (Sep 3, 2013)

THANKS TO ALL OF YOU WHO RESPONDED TO THREADS. I HAVE LEARNED A LOT ALREADY(MOSTLY THAT I DON'T KNOW WHAT I'M DOING)I DO HAVE A QUESTION FOR GA2500EV. DID YOU MEAN TO RUN JUST ONE SET OF BATTERIES FOR BOTH ENGINES? I HOPE TO GET 4 HRS OF RUNNING TIME A DAY. IS THIS REALISTIC, OR AM I JUST SPINNING MY WHEELS? I AM RETIRED AND PLAN TO TRAVEL WITH THE BOAT, AMD FIGURED 4 HRS. WOULD GIVE ME AMPLE TRAVEL TIME, AS I WOULD BE ABLE TO TIE UP AT A NEW PLACE AND EXPLORE OR JUST SET AROUND(WHICH I'M GOOD AT) EVERY DAY. THANKS AGAIN FOR YOUR HELP. bobsmith


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## bobsmith (Sep 3, 2013)

*ev boat*

WELL, HERE I GO AGAIN. ga2500ev GAVE ME SOME EXCELLENT ADVICE, BUT AS ALWAYS NEED MORE. ARE YOU SAYING THAT I ONLY NEED ONE SET OF BATTERIES FOR BOTH MOTORS OR ONE GOOD SET FOR EACH. I AM INTERESTED MORE IN HRS. AVAILABLE THAN IN SPEED. OF COURSE I WANT ENOUGH POWER TO BUCK SLOW CURRENTS, BUT AM PERFECTLY WILLING TO SACRIFICE SPEED TO GET LONGER RUNNING TIME. I AM STILL IN THE GETTING STARTED PHASE, WAS GOING TO POST SOME PICS. UNTIL I DISCOVERED MY CAR WAS BROKEN INTO AND MY CAMERA IS ONE OF THE THINGS THEY GOT AWAY WITH. WILL GET SOME PICS. ON AS SOON AS I REPLACE IT. THANKS AGAIN FOR ALL THE ADVICE I'VE BEEN GETTING,bobsmith


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## Woodsmith (Jun 5, 2008)

Hi bobsmith,

I have merged your post above with the rest of your boat controller thread.

Please try to keep your replies within the thread instead of starting a new thread to post a reply.

If you are having difficulties posting then let me, or any of the other administrators, know and we can try to help you.


Also, typing in block capitals is seen as 'shouting' on the internet and is not taken politely. It is also difficult for people to read.

Thank you,

Admin


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## bobsmith (Sep 3, 2013)

Taken with a grain of salt. I , didn't know about using capital letters. I use the peck and seek method of typing and easier for me to see what I wrote, but I'll not do it again. Will try to post pics. of my project soon as I get new camera. Thank you, bobsmith


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## bobsmith (Sep 3, 2013)

Thank you so much ga2500ev. I have been wondering exactly what a controller does and you explained so even I can understand. I just don't know which one would be suitable for my application. I found a rep. at clark that can get me the exact controller that came for the 48v engines I have but I don't know if that will be enough to run my boat for 4 hrs. a day or what kind of power I would have. Any input would be appreciated. Thank You, bob


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## Roy Von Rogers (Mar 21, 2009)

Why don't you contact these people, tell them what you want to do, they can give you some recommendations of what to do, with whatever boat you have.


http://www.newelectric.nl/


Roy


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## ga2500ev (Apr 20, 2008)

bobsmith said:


> Thank you so much ga2500ev. I have been wondering exactly what a controller does and you explained so even I can understand.


Glad that it helped.



> I just don't know which one would be suitable for my application. I found a rep. at clark that can get me the exact controller that came for the 48v engines I have but I don't know if that will be enough to run my boat for 4 hrs. a day or what kind of power I would have. Any input would be appreciated.


Controllers are rated by voltage and maximum current. Also be aware that motors (combusion devices are engines, electric devices are motors) can often run at higher than their rated voltage without an issue. There's two reasons why this is important and useful. The first is that the maximum speed of a motor is determined by the voltage you put into it. So running a high voltage on it gives you the ability to have a higher top speed.

Now the second item is a bit more subtle. Motors are powered by energy, which is measured in Watts. Watts is the product of Volts times Amps. So 50V @ 100 Amps delivers the same energy as 100V @ 50 Amps. Specifically 5000 Watts.

The subtle part comes back to efficiency. Wires are used to deliver power from the batteries to the controller then to the motor. All wire has a resistance, which instead of delivering energy to the target, instead it gets converted to heat, which is wasted. Thicker wire has less resistance, so there are ways to compensate. The point is that the amount of power wasted goes up linearly with voltage, but goes up SQUARED with the current. So if you double the voltage, the waste is doubled, but if you double the current, then the waste goes up by a factor of 4.

So for efficiency it's almost always better to deliver power at the highest voltage you can That's the reason that high power lines are in the kilovolt range, while house power is 100-400V.

The run time for your motors is strictly related to the capacity of your batteries, the amount of solar power you have, and the efficiency of the delivery system. The only factor that the controller has is its maximum voltage. If you can run your motors at 72V, but you only have a 48V controller, then your system is limited to 48V which caps your max speed and the efficiency of delivery system.

So the first thing to determine is that maximum voltage you can run your motors. The second which typically needs to be done empirically, is to find out how much power you need to deliver to the motors in order to do the task you want them to do. Then and only then can you determine the size of the batteries yous need.


> Thank You, bob


Welcome. Hope it helps.

ga2500ev


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## bobsmith (Sep 3, 2013)

And again I thank you. I'm not stupid, but I'm finding out There is a lot I need to learnabout running a dc conversion before I leave port. lol My daughter is going to post a bunch of pics. for me today, because my camera was stolen when my car was burgularized. With the info supplied with my motors when I purchased them they will run at 120v dc. How does this factor in figuring the amount of battery power I will need to run approximately 4 or more hrs. a day. I hope to run lithium, but worry about the fire factor, or is this overblown. Again I thank all of you for your comeback, bob


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## ga2500ev (Apr 20, 2008)

120 VDC is a good thing. As I said higher voltage means less losses.

Lithium iron phosphate (usually named LiFePO4) do not have the fire risks that plagued other Lithium chemistries. A detailed description of LiFePO4 in marine applications describes it as safe to use in marine applications.

As a stated before, you'll probably need to actually test to see how much capacity you need. One way to estimate your usage is to use the concept of Gasoline Gallon Equivalent. How many gallons of gas does it take to run 4 hours. The electrical equivalent of a gallon of gas is 33 kWh. Note this is at 100% efficiency, which gas simply cannot achieve. The page describes and example:



> One important point that somewhat clouds the practical utility of a GGE for comparing different fuels to each other is that machines which run on them produce usable energy from different fuels at different efficiencies. For example a 2012 Nissan Leaf has a battery capacity of 24 kWh, or a GGE size of 0.72 gallons. A standard small gasoline-powered car with 25 MPG efficiency can go 18 miles on this much fuel. But the higher efficiency Nissan Leaf can go 80-100 miles on this much battery charge.


The lack of efficiency of gas is because most of the energy gets burned up as heat. You can expect somewhere between 20-25% efficiency to the propeller. So if 4 hours takes a gallon of gas, the GGE is 33 kWh @ 25 efficiency, or about 8.25 kWhr. To get the Ahr capacity needed you divide by the voltage. So if it's 120V, then the amp hour capacity is 8250 kWhr/120V = 68.75 Ahr. So a 70,80,90, or 100 Ahr cells can be used. The nominal voltage of a cell is 3.2V, so you'd need 120V/3.2V per cell = 38 cells.

As a sample Evolve Electrics has 70 Ahr Calb cells for $98 each for 38 cells. So your "gas tank" for 1 GGE would be a shade over $3700 USD + shipping.

These are just examples. I don't know what your usage actually is. My hope is to guide you on how you can figure it out for yourself.

Hope this helps,

ga2500ev


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## bobsmith (Sep 3, 2013)

It certainly does(help I mean) I still have a question. Major told me and you agreed, that using extra batteries was redundant. I will still need one set for each motor, right. I had already figured about 7 grand for batteries, so I guess I wasn't far off. I have some pics. of motors and boat but haven't figured out how to load them to this web site. will try to get them on today. Also have aquestion about cooling batteries. Is this necessary in my application and do you have any suggestions as to how. Thank You again for all your help, bob


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## Tesseract (Sep 27, 2008)

bobsmith said:


> ...using extra batteries was redundant. I will still need one set for each motor, right.


Nope - you can use one battery pack to supply multiple controllers. That said, you might not need multiple controllers, depending on what kind of motors you are using and how much continuous power you need.



bobsmith said:


> Also have aquestion about cooling batteries. Is this necessary in my application and do you have any suggestions as to how. ...


No, you rarely need to cool batteries. There are exceptions, but you are unlikely to need to worry about them unless you plan on making your battery pack out of laptop or RC toy cells.


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## bobsmith (Sep 3, 2013)

Alright; I have uploaded my pics. to a web site. Hope this works. The url for this is https://dadspicsboatmotor.shutterfly.com/pictures there is a pic. of one of the motors,my boat, where the motors will be connected and the back deck, which we just finished.


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## Brute Force (Aug 28, 2010)

I'll through this out there as a thought on the dual battery packs: I think it's a good idea. But not one for each motor, have them set up to be able to switch between the two. Run off of the first pack until it's low, then you switch to the second and know that your excursion is half over. In theory, you should always be able to get back to port if you turn around when you switch batteries. Roadside assistance is difficult when your not actually on a road.


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## bobsmith (Sep 3, 2013)

Thank you again, everyone is so helpful its overwhelming. Now I need some help finding a supplier for the splined stock I need to make connection from the motors to the props. I purchased my motors before joining this site, or I probably wouldn't be in this situation. My motors have female splined connections about 5/8". I have found a machine shop in St. Louis, Mo. that can make them but the cost is so much I could buy different motors about as cheap. I live in Illinois so if anyone out there knows a source, it will be appreciated. I am trying junk yards, and bearing dealers but so far no luck. Thank you again for all the help, bob


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## ga2500ev (Apr 20, 2008)

bobsmith said:


> Thank you again, everyone is so helpful its overwhelming. Now I need some help finding a supplier for the splined stock I need to make connection from the motors to the props. I purchased my motors before joining this site, or I probably wouldn't be in this situation. My motors have female splined connections about 5/8". I have found a machine shop in St. Louis, Mo. that can make them but the cost is so much I could buy different motors about as cheap. I live in Illinois so if anyone out there knows a source, it will be appreciated. I am trying junk yards, and bearing dealers but so far no luck. Thank you again for all the help, bob


Surplus Center. Wide variety, great prices. Download their catalog and take a look. 

ga2500ev


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## bobsmith (Sep 3, 2013)

You're great ga2500ev. Didn't find exactly what I'm looking for, but found a cheap hydraulic cylinder with a 5/8" spline,, 9 tooth, exactly what I'm looking for. If worst comes to worst, and I can't find anything else I think I'll waste 50 bucks and see if I can salvage the shaft. really hate to do it that way, but I, may be forced into it. 100 dollars is a lot cheaper than I was quoted to make them. Did you see pics. of my project. back a couple of replies. Thanks again for all the help, bob


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## Duncan (Dec 8, 2008)

Hi Bob
Have you done an energy budget for your conversion?

I ask this because gasoline or diesel are incredibly energy dense 
120 Mega Joules/gallon = 30Kwhours

a 100 gallon tank of petrol contains a huge amount of energy - 3,000Kwhours
OK the efficiency is only 1/3 of en electric motor but that is still 1,000Kwhours equivalent
*or $300,000 in batteries*

This means that you can't simply replace a boat diesel with electric motors

On the good side boats can be operated on very low energy budgets - the main thing is to go at below "hull speed" - probably about 8 knots for a boat like yours
Your boat can probably cruise at 6 knots on about 3Kw (4Hp)

Four hours at 3Kw = 12 miles = 12kwatthours - $4,000 in batteries - doable

Above "hull speed" the power needed goes up very fast
Cruising at 12knots will probably require 40Kw

Two hours at 40Kw = 12 miles = 80kwatthours - $20,000 in batteries -


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## Tesseract (Sep 27, 2008)

Two minor quibbles, Duncan:



Duncan said:


> ...
> I ask this because gasoline or diesel are incredibly energy dense
> 120 Mega Joules/gallon = 30Kwhours


First is that 120MJ = 33.3kWh; with the additional caveat that the range is something like 33-38kWh per gallon depending on seasonal variations in formulation. The energy content of diesel is a bit higher, but I don't remember the number off the top of my head and am too lazy to go look it up.



Duncan said:


> ...OK the efficiency is only 1/3 of en electric motor...


Second is that the efficiency of the the typical automobile engine (and just the engine) is more like 20-25% (though diesel is higher here, too), so 1 gal. of gas is roughly equivalent to 6.6-8.3 kWh. That still blows any battery out of the water... ahem... hence why I said my quibbles were minor.


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## bobsmith (Sep 3, 2013)

Hi again, and thanks again for the input. I will be happy if I get4-6 knots from the motors and be able to run 4-5 hrs a day. I plan to cover the boat(has a lot of roof surface)with solar panels. someone did the math for me and figured I would need approximately 38 lithium batteries to do this. I plan to run this many to each motor,even though I have been told I don't need to. each motor will run with separate controllers, completely independent of each other. If it takes more batteries, I will buy more. My plans for this have been going on for many years and I will see it through to the end. My goal is to have a liveaboard that never has to touch shore and I am willing to spend the money to see it through(within reason) lol We recently took a battery powered drill, hooked to an old prop off a six horse motor and ran my fiberglass 14' faster than the 7 1/2 horse with which I normally run it. It ran for about 20 mins. total. we had a blast, just holding it over the back of the boat and running around the lake till it ran out of juice. This tells me that my motors should at low rpms move my big boat rightalong with little drain on the battery pack. I know that I am going to get a lot of argument over this, and that is what I want. I want to know every problem I could run into doing this. Thanks again and hoping to hear from you again, bob


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## Duncan (Dec 8, 2008)

Hi Bob
Two independent systems - makes sense for a boat

Energy efficiency
What you are doing is essentially throwing water backwards
Thrust = mass flow rate x exhaust velocity
Energy = 1/2 mass flow rate x exhaust velocity *squared*

So the greatest efficiency (most thrust per energy used) is if you throw a lot of water slowly

So - the biggest (diameter) prop that you can fit moving at a nice low speed

Prop pitch - there will be an optimum pitch - this will enable the prop blades to "fly" through the water at a good "attack angle" like the wings of a plane


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## bobsmith (Sep 3, 2013)

Exactly, if I can turn the props (they are about 14" in diameter) 500 revs, I figure to travel right along But I am having a different problem right now. I can't find the 5/8" spline I need to make the driveshafts I need to run the props. Wish I had found this site first, I wouldn't have purchased a motor with this problem. But, that's in the past. I have them and I will make them work. Last night I read a 14 page forum on batteries(specifically LiFePo) Do u still have to balance a pack of them or have they progressed in production so this is not necessary. Thanking You All again for everything I'm learning from this site, bob


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## Roy Von Rogers (Mar 21, 2009)

You should always empty the pack to about 2.7v per cell, let the pack sit for 24 to 48 hours and recheck, and than put an amp hour meter on it, and charge it. The first cell that hits 3.5v will be your pack capacity.

You want to do that no matter what, for no other reason to make sure all cells are good, and to know what your max pack is.

You can to that with each individual cell, but its easier to do it with above procedure.


Roy


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## bobsmith (Sep 3, 2013)

Thank you Roy, now if I could just find the splined shaft I need I could start installing everything. going to check out some hydraulic shops as I have been told they use a lot of small diameter spline shafts. I noticed one thread written in the fall that said something about not getting his batteries until june. does it take that long when ordering? If so I'd better get at it. Thanks again for getting back with the answer to my battery question, as always bob


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## Roy Von Rogers (Mar 21, 2009)

Have you tried lift truck places, to see if you can get whatever fits to your motors, and then have someone weld a shaft up to it.

Roy


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## major (Apr 4, 2008)

bobsmith said:


> Thank you again, everyone is so helpful its overwhelming. Now I need some help finding a supplier for the splined stock I need to make connection from the motors to the props.


Been outta state at battery school. Be back home tomorrow. Anyway, checking up here I see you have MLV type Prestolite motor(s). Those are real strong 7.2 inch diameter series wound machines. Yep, 9 tooth internal spline, SAE standard 16/32 DP tooth form. You should be able to find splined stock to fit....... somewhere.

And I think I recall you mentioned reversing. The motor is unidirectional. Major modification is required to make it reversible; adding 2 terminals.


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## bobsmith (Sep 3, 2013)

Great to have guys like you to lead a lead head like myself. Major, which would be easier, tranny or adding the two terminals. I have the original trannys that went to the engines. They are simple forward, neutral and reverse. I don't think it would take much to hook them up, I still have the cables to cabin and flybridge. I would really like to avoid using them if possible, but don't know what expertise is needed to add the new terminals. Roy, thanks for the advice on the batteries, don't want to spend 8 grand and watch it go down the drain. Thanks again, bob


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## major (Apr 4, 2008)

Probably the tranny, especially if it has a decent reduction ratio.


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## ga2500ev (Apr 20, 2008)

bobsmith said:


> Hi again, and thanks again for the input. I will be happy if I get4-6 knots from the motors and be able to run 4-5 hrs a day. I plan to cover the boat(has a lot of roof surface)with solar panels. someone did the math for me and figured I would need approximately 38 lithium batteries to do this.


I just worked that out by the numbers you gave me. You said that the max voltage on the motors was 120V. Each cell has a nominal voltage of 3.2V. So 120V/3.2V = 38 cells.


> I plan to run this many to each motor,even though I have been told I don't need to. each motor will run with separate controllers, completely independent of each other. If it takes more batteries, I will buy more. My plans for this have been going on for many years and I will see it through to the end. My goal is to have a liveaboard that never has to touch shore and I am willing to spend the money to see it through(within reason)


You've now thrown in a couple of wrinkles I had not seen before. Let me throw out an analogy to help you visualize the problems. Consider if the batteries were a water tank that's used to drive paddle wheels to move the boat. Let me ask some questions about the system.

1. If you were going to drive 2 paddles, would you build 2 water tanks one for each paddle? Or would you use one bigger tank and use piping to direct the water to the two different paddles from the larger tank. If you used two tanks, then what exactly would you do if one tank was empty while the other still had water in it?

2. To drive the paddles, you draw water from the tank. Obviously you need to put more water into the tank in order to keep driving the paddles. What exactly happens when the paddles use more water than you can pour into the top? Even if the tanks started full, eventually you would run out of water, would you not? Then you'd have to stop the paddles and let the tank refill before you can use them again.

Once you have answered these questions you can apply the answers to your system using the following mappings:

Tank: batteries
piping: controller
Poured water into the top: solar
paddles: motor

Hope this helps you to think about how you put your system together.

ga2500ev


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## bobsmith (Sep 3, 2013)

Well, you always leave me with more questions than answers. I like that. Will one controller run both motors equally. I mean can it make them both run at the same speed. I figured that with two sets of batteries and two controllers I would be able to do that. I only plan to run whatever I could with the batteries resting and recharging when at about 50%. I know the solar cells will probably not be able to keep up with the discharge. especially on cloudy days. So are you telling me to just run one set of batteries or to run two sets and have one charging all the time. Or are you saying to get a larger set of batteries and run both motors together. Haha, I always have more questions than answers, and I know you are trying to get me to think for myself, and myself still wants two separate units. On good days in calm waters, I could run just one motor, and always have one in reserve. Or I could run both and run them much slower, and on bad days I would have the strength of both motors and both sets of batteries. If I can accomplish this with one set of batteries and one controller, I would certainly like to keep from spending the extra money. As always I thank you for your input, bob ​


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## Duncan (Dec 8, 2008)

Hi Bob
As a boat I think the two independent systems are a good idea - and will only cost a small amount more

Two motors, - you have
Two controllers
Two batteries - but the same size and cost as a single battery
Two sets of solar panels - but the same size and cost as a single set

Wire it up as two separate systems with the ability to switch across
The solar panels should be connected all of the time - they can be charging while the motors are drawing current

Drive it using both motors - keep an eye on both fuel tanks (batteries) 
When necessary - balance the "tanks"

If anything fails - drive home on the remaining system

It will be most efficient to operate using both motors (effectively a bigger prop)

The only extra cost over using a single system is two controllers - and the elimination of any single point of failure should be worth that

As far as voltage is concerned
A DC motor controller is a power in - power out device
It feeds the motor with the voltage it needs
So a motor with a max voltage of 120v - can be fed from a 200v battery 

In a car it makes sense to go for the highest voltage you can
This is because you need a LOT of power for a short period (accelerating)
In a boat you need a medium amount of power for a longer period
So sticking to a much lower voltage may make sense 
48v ????

I suspect 48v will be enough to drive those motors at their continuous maximum power limit
Major - would that be correct??


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## major (Apr 4, 2008)

Duncan said:


> I suspect 48v will be enough to drive those motors at their continuous maximum power limit
> Major - would that be correct??


The MLV type Prestolite motor was a 36/48V lift pump motor (fork truck). It was rated for a 20% time-on 5 minute base duty cycle at somewheres north of 300A; maybe 350. Intended for intermittent duty. It would have a continuous rating of around 200A if ventilated with its internal fan. It was one of the most efficient laminations in the product line. So at 48V, 200A would have pumped out 10 horse continuous. That might have been around 3 kRPM. You could push that up with higher voltage and maybe get 20 hp but she'd be screaming at like 6 grand and probably run a bit hot.

This all depends on his prop and the transmission ratio as to what load and RPM. And then you have the fact that the motor controller decouples motor voltage from battery voltage, so he could run a high voltage battery and keep the motor V lower. I'd recommend keeping it below 4000 RPM and 200A for happy sailing. But it'd do 4 or 500A for a minute or 2 if you wanted to show off.

I'd get an overspeed cut-off protection circuit on it if there is any chance of the prop coming out of the water or tranny going into neutral.


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## Duncan (Dec 8, 2008)

Thanks Major

So my take would be that you could use two 48volt systems - using up to 200amps

That would give 20Hp - for use in emergencies 

Continuous "cruise power" would be more like 1.5Kw each motor - That would be about 31 battery amps (at 48volts)

So if you wanted six hours cruising you would need two packs
48 volt and 6 x 31 = 187 amphours

That would be 48v / 3.2 = 15 cells in series -
So each pack would be 30 off 100Ah cells arranged in two strings of 15
to give 48v and 200Ah

At ~ $150 each each pack would be $4,500 - $9,000 for both packs

At "emergency power" - 20hp you would have 1 hour

At 48v chargers and controllers are readily available and you are not mixing high voltages with water


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## bobsmith (Sep 3, 2013)

I now have more questions. First let me say that I plan to travel with this boat. Mainly, the rivers and intercoastal waterways of the United States. If I could get 6 hrs. of travel a day, that would be awesome. I am still hunting for the 5/8"? splined shafts I need, but have everything else pretty much on course. A Clark Equipment Dealer says he can get me the original controllers for these motors for $450 each. seems cheap enough. Would they work seen you say I should run them at 48v? Or would I be better off running a large pack, say 120v and letting the controller run the right voltage to the motors. Would I get more travel time with 4 different battery packs or 2 high v packs? As you can see I'll never be far from shore and a place to anchor when I get low on power, and like the idea that I may have to tie up to a point for a while so I can recharge . Give me a chance to see the country side. Major, thank you for finally identifying my motors. I don't see having to run them at more than 1000 to 1500 rpm, and even then will probably move right along. With 14-15" props, it doesn't take much to move my boat. In fact the desiel engines would push it right along at almost an idle. Duncan, your batteries are to high, ga2500ev says I can get them for 85 per cell, haha. I really thank you all for all of your input, as always, bob


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## major (Apr 4, 2008)

bobsmith said:


> I don't see having to run them at more than 1000 to 1500 rpm, and even then will probably move right along.


I suggest running the motors at about 2000 - 2500 RPM for your long cruises. That will keep the motor current lower and provide proper air movement thru the motor. Of course you'll be lower on RPM during slow speed maneuvers and higher RPM when going faster or fighting current or wind.

Another thing: This motor, being a pump motor, probably did not use a controller in the fork truck. It might function perfectly well from the truck's traction controller, may not


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## ga2500ev (Apr 20, 2008)

bobsmith said:


> Well, you always leave me with more questions than answers. I like that. Will one controller run both motors equally. I mean can it make them both run at the same speed. I figured that with two sets of batteries and two controllers I would be able to do that.​




One controller to two motors may generate unequal loads. So the motors may operate at different speeds in that situation. If you read my post carefully, you will see that I'm suggesting that one battery bank and two controllers may be the best setup.



> I only plan to run whatever I could with the batteries resting and recharging when at about 50%. I know the solar cells will probably not be able to keep up with the discharge. especially on cloudy days. So are you telling me to just run one set of batteries or to run two sets and have one charging all the time.


The former. If the solar bank is putting in the same amount of energy, it really doesn't matter if that energy goes directly to the motors (in the first case), or to a charging battery bank for later. The capacity in theory is the same. So for simplicity, have a single battery pack. It'll be easier to manage.


> Or are you saying to get a larger set of batteries and run both motors together.


Of course. You should get the largest battery pack that your boat and budget can support and use all of it all the time. There's no good rationale for trying to split it and have a reserve bank.


> Haha, I always have more questions than answers, and I know you are trying to get me to think for myself, and myself still wants two separate units. On good days in calm waters, I could run just one motor, and always have one in reserve. Or I could run both and run them much slower, and on bad days I would have the strength of both motors and both sets of batteries. If I can accomplish this with one set of batteries and one controller, I would certainly like to keep from spending the extra money. As always I thank you for your input, bob


You'll need two controllers because it may be necessary to give the two motors different amounts of energy to run the same speed. Also it will facilitate your need to be able to run a single motor at a time.

All of my discussion has been targeted on the battery pack. In all cases it should be an "All In" situation. As many cells as you can, all connected together.

ga2500ev


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## ga2500ev (Apr 20, 2008)

Duncan said:


> Hi Bob
> As a boat I think the two independent systems are a good idea - and will only cost a small amount more
> 
> Two motors, - you have
> ...


I disagree (respectfully of course). The real cost is the added complexity of setting up and maintaining such a system. It doubles the number of potential failure points and complexifies the process of sharing energy across the pairs.
Battery packs need to be balanced and monitors. With two of them, you now have twice the work to keep track of. Same with the solar system. 

In my opinion all the energy should be concentrated into a single system and only the distribution via the controllers be split.



> As far as voltage is concerned
> A DC motor controller is a power in - power out device
> It feeds the motor with the voltage it needs
> So a motor with a max voltage of 120v - can be fed from a 200v battery
> ...


I disagree again, but for a different reason. You are correct that the controller is a power in/power out device. The voltage is important though because power losses go up linearly with voltage, but goes up with the square of the current. Bottom line is that if you run at the lower voltage, you'll lost more energy in the wires, and because of the higher current demands in order to maintain the same power level, all the wiring in the system will have to support the higher current output.

Since the controller is designed to manage the motor voltage, it's always best to run the battery pack nearer to the highest voltages the motors can support, no matter what average voltage (and therefore RPMs) you plan to execute. Higher voltage, lower current, shorter pulses are better than the opposite, even if the average speed is going to match the lower voltage.

ga2500ev


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## Duncan (Dec 8, 2008)

ga2500ev said:


> In my opinion all the energy should be concentrated into a single system and only the distribution via the controllers be split.
> 
> 
> Since the controller is designed to manage the motor voltage, it's always best to run the battery pack nearer to the highest voltages the motors can support,
> ga2500ev


Hi Ga2500ev

For a car I agree entirely - to both 

However for a boat,
Two totally independent systems make a lot of sense
In a car a power failure is embarrassing and can be dangerous
In a boat it could be fatal
When I go Scuba diving I always have two independent air sources

A single battery would reduce the connections - but very little else
You will still need the same number of the expensive bits (cells)

Voltage
Again for a car - go high! - you will be pulling 100's of amps 

In this case the normal current flow will be ~ 30 amps
AND you are in water - 
High voltages do not go well with water!

If you keep to 48volts - 
It is a lot safer
You can use cheaper (ex-forklift) parts

Hi Bob
Re - price of cells, that was price from one of the advertisers on this site
If you can get cells for about half that - Go for it!


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## ga2500ev (Apr 20, 2008)

Duncan said:


> Hi Ga2500ev
> 
> For a car I agree entirely - to both
> 
> ...


It's not a matter of cost. As I stated it's a matter of complexity.It's easier to monitor one system as opposed to two. One system will have single points of failure, I agree. But two systems will have double the number of potential points of failure.Consider the situation where one of your independent systems is out of power and the other has a controller failure. Still dead in the water.



> Voltage
> Again for a car - go high! - you will be pulling 100's of amps
> 
> In this case the normal current flow will be ~ 30 amps
> ...


It doesn't matter if it's 48V or 120V. Both require watertight systems to prevent failure. With a primarily solar powered system, eficiency should be of great concern. Also weight should be an issue. If your current flow is 30 amps @ 48V, then it'll be less than 10 amps @ 120V with a lighter and more efficient power delivery system There's a reason that power is shipped across the continent using 25 kV lines and not 240V ones.

ga2500ev


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## Duncan (Dec 8, 2008)

Ah well ga2500ev we will just have to disagree and I will continue to dive using two independent air supplies


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## ga2500ev (Apr 20, 2008)

Duncan said:


> Ah well ga2500ev we will just have to disagree and I will continue to dive using two independent air supplies


We're not diving here. The difference is that when diving, a system failure only allows for minutes to pass before it is too late. With a boat, if a system goes out, unless there is rapids nearby, there is no imminent threat that requires an instantaneous fix. Even if there are rapids, a quick drop anchor should be enough to keep the boat still until the problem can be diagnosed and fixed.

We do disagree. In this case simplicity should override safety because of the different scales of time that must elapse before the situation is urgent.

ga2500ev


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## bobsmith (Sep 3, 2013)

Well, I am glad to see all of you taking an interest in my project. I think I can settle this in a way that will satisfy you both. I am going to run 38 cells for the main bank of batteries, but will need another to run all of the acc.s on board, refer, radar, tv, etc.ect. Would it be possible to wire the second set so I could disconnect from accessorys and run my motors if necessary. I'm hoping it could be a smaller pack, but if necessary could run another 38 cells. I think 48v would be enough to run the boat, so am hoping a smaller pack would suffice for stand by,as the only thing will be on continuously is radar. As I said I plan to stop frequently, and would be happy with 5hrs. of running time a day, and would have the second pack always there just in case. I do have a question for Major, is it possible that when you I.D.'d my motors that you meant the shafts were 19/32. The reason I ask is that when I measure them with a tape measure, they come up 5/8" I know this is not a very reliable measurement, but want to be hunting for the right spline. Thank you all for your input once again, bob


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## major (Apr 4, 2008)

bobsmith said:


> I do have a question for Major, is it possible that when you I.D.'d my motors that you meant the shafts were 19/32. The reason I ask is that when I measure them with a tape measure, they come up 5/8" I know this is not a very reliable measurement, but want to be hunting for the right spline.





major said:


> Yep, 9 tooth internal spline, SAE standard 16/32 DP tooth form. You should be able to find splined stock to fit....... somewhere.


DP = Diametral Pitch of the involute. Ref: http://quickgear.bizland.com/id11.html Or sometimes referred to as just the pitch. Ref: http://www.engineersedge.com/gears/involute_spline_engineering_drawing_data_10088.htm 

So it is not a diameter which I think is what you are measuring.


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## bobsmith (Sep 3, 2013)

Major, thank you, I don't quite understand, but I see what you were referring me to. I studied the threads and can see what you were trying to tell me. when I say I don't understand, I really am asking, is this the size I should be using to find the right spline? Thanks for your time, bob


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## major (Apr 4, 2008)

bobsmith said:


> Major, thank you, I don't quite understand, but I see what you were referring me to. I studied the threads and can see what you were trying to tell me. when I say I don't understand, I really am asking, is this the size I should be using to find the right spline? Thanks for your time, bob





major said:


> Yep, 9 tooth internal spline, SAE standard 16/32 DP tooth form. You should be able to find splined stock to fit....... somewhere.


I think that defines the spline size as well as the tooth profile. An inside diameter (minor dia) measurement wouldn't hurt as a reference. I believe it is an SAE and/or ANSI standard used extensively in the industry. From memory, all the dimensions are defined in the SAE handbook. But a machine shop or vendor should recognize it as I described. Obviously a trial fit before you buy is a good idea.


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## bobsmith (Sep 3, 2013)

Major, thank you again, I don't know what those of us who don't have the knowledge you possess would do without a web site like this. I will start looking for the right spline to connect my motors to the tranny's today. Again thank you so much for your help, bob


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