# Building an EV lawn tractor



## procupine14 (Mar 17, 2010)

Greetings all! I have decided (for fear of screwing up expensive things and the fact that my father and I have a FEW donors to choose parts from) that I am going to build an EV lawn mower first and once it is complete I will go on to a full on car. Already have a donor for the tractor side of my build. Its a 1960's Cub Cadet with a blown motor and basically brand new gearbox. I also have an electric golf cart that I found on craigslist that I will be looking at later on this week (probably the weekend). 

I know that a lot of the guys that have done tractors are posted over in the bikes thread and here and there but I thought I would just toss this in here since it is a build thread. I am working on getting more information on the golf cart. The guy said that it is all electric and the only thing wrong with it is the battery pack is toast. the motor and all of the other electric bits are in complete working order . Any suggestions on this whole build? I plan on snagging up either a small auxiliary motor to power the deck or running it off of the belt system that the tractor itself has. The mower is a shaft driven garden tractor so the belts that run the deck are attached in between the clutch assembly for the deck and the clutch assembly for the transmission. 

So I guess my first question is: 
what are thoughts about both sides of this issue? Either running a pulley off of the shaft ahead of the clutch assembly to power the mower deck or just running a separate motor for the deck. The deck is entirely belt driven so either way won't be too difficult to pull off.

Also, I plan to retain the clutch/friction brake for safety (duh) but it really isn't very useful outside of that correct? Because if I go with separate motors the deck will spin at a constant speed and the motor will have to be essentially shut off before engaging the clutch for the purposes of not killing the motor buy letting all of the load off of it. Is this pretty accurate?

Have to also thank all the guys that contributed to this mower thread right here on DIYEC where I've been soaking up all kinds of knowledge


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## Jimdear2 (Oct 12, 2008)

I did a conversion on a cub cadet 100 The conversion I did was for tractor pulling. Try the link below and then feel free to contact me for more information.

http://www.diyelectriccar.com/forums/showthread.php?t=28942

I'll be glad to help out.


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## procupine14 (Mar 17, 2010)

Ok awesome thanks! So I guess that it is safe to assume that something like a golf cart motor would be more than adequate for shuttling this tractor around the yard? I will post pics of the tractor soon. It's currently sitting in my father's shop so I will have to go over there and snap some shots. 

What do you think about running separate motors for the deck and the traction setups?


sharing something funny about this tractor to give you an idea of the time period its from. It has a working cigarette/cigar lighter  hahaha


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## electromet (Oct 20, 2009)

Procupine, 

That cigar lighter ought to work really well on a 48v pack. I'd shave before I tried it, though.


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## Jimdear2 (Oct 12, 2008)

procupine14 said:


> Ok awesome thanks! So I guess that it is safe to assume that something like a golf cart motor would be more than adequate for shuttling this tractor around the yard? I will post pics of the tractor soon. It's currently sitting in my father's shop so I will have to go over there and snap some shots.
> 
> What do you think about running separate motors for the deck and the traction setups?
> 
> ...


 
OK First of all, I recomment that you find something other then a golf cart motor. I tried using one and gave up. The golf cart may yeild a good controller and relays and wiring though.

Most golf carts use the differential case as the drive end cover of the motor and the armature has a female spline that engages onto the differential pinion shaft. You can make an end cover and output shaft but you will need at least a lathe. Look at Woodsmith's tractor building thread and you will see the difficulties he went through. I also recomend that you read the sticky thread about choosing a motor found on the MOTORS page.

ACcub is a easy conversion because of the driveshaft. I do recommend that you DO NOT use the clutch. with a little rework you will still have the wet brake in the transmission working. You can buy shafting to replace the existing shaft if you mount the motopr way forward. If you mount it as far back as you can all you will have to do is shorten the shaft and redrill the spiral pin hole. 

Finding places to locate big batteries will be a problem (I went with small batteries because of weight limits in pulling) but be creative and you will sucseed


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## procupine14 (Mar 17, 2010)

Jimdear2 said:


> ACcub is a easy conversion because of the driveshaft. I do recommend that you DO NOT use the clutch. with a little rework you will still have the wet brake in the transmission working. You can buy shafting to replace the existing shaft if you mount the motopr way forward. If you mount it as far back as you can all you will have to do is shorten the shaft and redrill the spiral pin hole.
> 
> Finding places to locate big batteries will be a problem (I went with small batteries because of weight limits in pulling) but be creative and you will sucseed


Ah ok that sounds good. would it be ok if I retained the friction brakes? all of the cubs we own have them and I feel like it would be really nice to keep them for hills and such on our land where the transmission brake still allows roll. I assume that would be something that you reccomend anyway but I thought I would check. 

I see what you are saying about the golf cart motor. That seems like a pain. I might just go ahead and pick up the car anyway and just see what I can and can't salvage from it. I asked the guy that owned it to send me some pictures and I haven't heard back from him other than him saying that it wasn't the prettiest looking thing (which I could care less about) and that he wanted just $100 for it which I think could be a steal if all of the wiring is in good condition.


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## Woodsmith (Jun 5, 2008)

Ooooh! Another EV tractor!

I wouldn't worry too much about the motor. If it comes with the golf buggy then that is great. It doesn't stop you getting a motor from elsewhere.

You would have an advantage over me as the transmission will be made of the parts I had to make up, ie. the DE cap and the splined shaft. Left in my hands I would be dismantelling the transmission to modify it to give me the output I want to use to connect to the cub. It might even provide more gear ratios.

I look forward to some photos.


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## Jimdear2 (Oct 12, 2008)

procupine14 said:


> Ah ok that sounds good. would it be ok if I retained the friction brakes? all of the cubs we own have them and I feel like it would be really nice to keep them for hills and such on our land where the transmission brake still allows roll. I assume that would be something that you reccomend anyway but I thought I would check.


Are your cubs hydrostatics? The only models I've seen external disc brakes on were hydros. Dual brakes on manual trans models are cool.

Hydros are NOT real good conversion material. You can do them but they are hard to adjust power on.

By the way if something I send you doesn't make sense, ask. I am an old two finger typest and I thickfinger a lot and with bad eyes I miss the mistakes.

[


procupine14 said:


> I see what you are saying about the golf cart motor. That seems like a pain. I might just go ahead and pick up the car anyway and just see what I can and can't salvage from it. I asked the guy that owned it to send me some pictures and I haven't heard back from him other than him saying that it wasn't the prettiest looking thing (which I could care less about) and that he wanted just $100 for it which I think could be a steal if all of the wiring is in good condition.


If cost and availability gets in the way maybe a golf cart motor might do. It just a lot of extra work. I beleive there were some golf carts that had separate motors so go look.

You will want a 24 or 36 volt motor with shafts at both end (more later on that) that will run ok at 48 volts (it will be hard to get more batteries for more voltage in something as small as a cub cadet) and make about 6 to 8 horse power. You need a motor that willl turn at least 3600 rpm (more is better, mine does around 5500) at 48 volts. I leave mine in 3rd gear for everything except pulling competition. The low end torque is awsome. Go to you tube and search for Cub Kazap. Every thing you see me do is in third gear. With stock 23 inch tires you will have even more power.


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## procupine14 (Mar 17, 2010)

Woodsmith:I will definitely be gracing this forum with loads of photos once everything is in order. Yeah I decided to do a tractor first. My father has a pretty big yard with lots to mow and, quite frankly, he's tired of dealing with gas lawn mowers. So what is a guy to do? Have a son that suggests electric and its off to the races!

Jimdear2: definitely not hydrostatic. It's got a good old standard three geared trans mission and reverse. My father's big mower is hydrostatic but we aren't playing with that one....yet  . It's an interesting little mower. Basically, it has a clutch and the pedal for the clutch is the clutch/brake pedal. Push it in about half way and you disengage the motor, all the way and you get brakes I do know that they are tiny friction brake drums because when I was younger we changed out a set on it. The only real benefit to it is that you won't roll on a hill while you have the clutch in. Like i said about the golf cart, we shall see. I don't feel like I'm out a lot of money if it has some things like a charger and a controller (at least as a starter set, probably will replace them later with better stuff as the project rolls along). There is quite a large area under the hood as this is a little bigger than just a basic lawnmower (as it fits into the "garden tractor" variety) so I think I will be able to fit some batteries here and there rather nicely.

Yeah I am thinking it will do pretty well as far as power. As long as it is able to haul my butt around and mow the grass it will be able to do everything that we need (my dad is a smaller guy than me so you know)


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## procupine14 (Mar 17, 2010)

Jimdear2,

I looked at your videos. Man that is one tough little tractor! So I'm thinking if your motor is able to do that I'm sure that something around the same power output to a little less would be more than enough for basic yard work etc.


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## procupine14 (Mar 17, 2010)

electromet said:


> Procupine,
> 
> That cigar lighter ought to work really well on a 48v pack. I'd shave before I tried it, though.


hahaha yeah I'm not sure I want to try it out on a 48v pack of batteries


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## procupine14 (Mar 17, 2010)

Well the guy with the golf cart seems to have fallen through on replying to my emails and such so I guess that means im back to looking for things. So I guess the first question comes on how much motor I need for this tractor. Right now its running a mid 20s hp Kohler motor so I assume that you need not even half of that to do the job. Looking at your tractor Jimdear it looks like yours is about a 5 horse motor and most golf carts are some where between 3 and 5 hp so my thought is something in that range will be a good fit. 

Any motor suggestions?


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## Jimdear2 (Oct 12, 2008)

procupine14 said:


> Well the guy with the golf cart seems to have fallen through on replying to my emails and such so I guess that means im back to looking for things. So I guess the first question comes on how much motor I need for this tractor. Right now its running a mid 20s hp Kohler motor so I assume that you need not even half of that to do the job. Looking at your tractor Jimdear it looks like yours is about a 5 horse motor and most golf carts are some where between 3 and 5 hp so my thought is something in that range will be a good fit.
> 
> Any motor suggestions?


 
Procupine,
Five to eight nominal hp at 24 to 36 volts and 3500 rpm sounds good to me, That's what I went looking for, you may decide on something else. 

There are so many variables that I can only give you the most vague suggestions. Below are some suggestions on what to look out for. 

First things first, READ the entire thread started by Jim Husted about finding a good lift truck motor. It's the first thread on the MOTOR page. It will take a while to read but it's worth it. Make notes and research

Another good read is the Forkenswift builds.

If you find something you like, get as much info as possible. Get pictures of the commutator and brushes if possible. Post what you have in the MOTOR page and maybe one of the motor experts will chime in

You will want a motor with male output shaft(s). Watch out for splines, tapers and odd shaft sizes. Be sure that you can make some form of coupler with out major rework. Watch out for odd shapes and mounting systems on the Drive End (DE) bell. Sometimes there are real deals for these odd motors. If you can handle the oddities you can make out.

Be sure the motor you buy is a series DC motor not a sepex or other variation If you are unsure ask and if you can't get a good answer PASS.
$500.00 boat anchors are not fun.

Be sure the motor has good (or repairable) fields, armature, brushes and commutator. If something needs repair as about costs before you buy.

Check with local motor rebuilders. Sometimes they fix a motor for someone and it never gets picked up. You can get good deals that way.

Check on eBay, there are a number of rebuilders that fix a bunch of motors and then sell them off. Be Real Sure Of Who And What. Again if your not sure, Ask or Pass

DON"T BE AFRAID TO ASK

Once you find a motor and decide on how much battery you can fit/carry/pay for we can get into more detal.

Have fun.


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## procupine14 (Mar 17, 2010)

Thanks a lot Jimdear. I suppose I will head on over the the motor thread to get some information. I was reading a lot about forkenswift's thread and on their website. This was when I was thinking about doing a car build first but now that I have to size everything down a bit things are different.


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## procupine14 (Mar 17, 2010)

Just a little update. Finally made the concrete decision on which tractor that I will use for the first conversion. I decided on the oldest and smallest of the cubs that we have around here since it's gas motor is completely seized up and not even remotely functional any more. The nice part about this particular mower is that it is all belt driven so perhaps playing around with the prospect of the mower deck running off of the tail shaft of the motor could be a possibility. If not I think I will still run a separate motor for the mower deck. I'm in the process of selling my truck to make room in the shop for this little project and still looking around for a decent motor. Really what I want to find would be a dual shafted motor now in order to weigh the possibilities of actually being able to run the mower deck off of the shaft facing the front of the mower. I have been doing some research and there are a couple of mowers out there on the market that are full on electric now so that has really given me a confidence boost on running my deck. Not to mention some of those mowers can mow for three hours. I probably only need about one hour so definitely not as much time as those things but I feel like I'm headed in the right direction  . Now, if I could just find a nice electric motor to fit the bill for this project.


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## procupine14 (Mar 17, 2010)

Alright here are all the beginning donor pictures. 









you can see the belt drive for the drive train really well in this picture.

























close up of the back of the seized gas motor.








and the front of it where the deck attaches as of now.


























As you can see, the deck isn't that large on this particular model (which is one of the reasons we decided on this one instead of the huge decks on the other tractors) so that definitely works in favor of actually being about to power it with a small motor. 

Hey Jim 
Here's that belt-driven Cub that you've been waiting to see!


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## Jimdear2 (Oct 12, 2008)

procupine14 said:


> Alright here are all the beginning donor pictures.
> 
> Hey Jim
> Here's that belt-driven Cub that you've been waiting to see!


Proc,

I did a quick bit of research. What you have there is a Cub Cadet Original. The very first Cub, It was produced between 1960 and 1963.

It looks pretty complete, before you tear it apart, it might be a good idea to see what value it has for collectors. There are quite a few dedicated Cub Cadet groups that restore these tractors. You should get on the internet and check.

You might get enough to finance your electric conversion of another of the more common models that you have.

Just a thought,
Jim


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## procupine14 (Mar 17, 2010)

Jim,

Yeah, my father and I have spoken about it. It has every single original part on it. We might have to have a talk and see what we wantto do about it. Going to have to check and see if it's worth anything to a collector. My grandfather was the one that actually bought this tractor brand new from the local Cub dealer that is actually still in business.


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## Woodsmith (Jun 5, 2008)

A one owner original, I would say that is worth restoring. A lot of early agricutural equipment gets lost due to being worked to death and then discarded so I would be tempted to save this one for a collection given you know the history.


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## Jimdear2 (Oct 12, 2008)

procupine14 said:


> Jim,
> 
> My grandfather was the one that actually bought this tractor brand new from the local Cub dealer that is actually still in business.


Proc,

You should check with the original dealer to see if they want to purchase it back to restore. Nice advertizement for them and for cub, they sold it 50 years ago and still working. Or some other drivel. 

Also look through forums like this one

http://www.onlycubcadets.net/forum/index.php

Some have want ad sections where you can get an idea of the value.

Jim


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## procupine14 (Mar 17, 2010)

We spoke to the original dealer about two years ago on how much money we would be able to get for it if we traded it in for a newer tractor. He told us that the most he would give us would be about $200 for it. I looked up some price charts from collector sites on how much these originals go for completely restored and less than $500 seems to be the going rate and basically the same price as the dealer offered us for the tractor as it sits. A lot of the problem is the old Kohler in it burned oil really bad before it completely died out (original motor by the way, not bad for 50 years of stump pulling and mowing, snow plowing etc) so most of the people we have talked to about selling it off have said that they would have to get an entire new motor (which is pretty much true) and with the economy the way it is we are having problems enough selling our 1980 restored street rod truck. We are going to talk about it a bit more but I think, in the end, we will end up sticking with this tractor for the conversion. It's not all bad really since we are trying to make it look as stock as is possible (being car restorers we don't like to cut factory metal too much) afterwards so the general thing will be that you could easily put a gasser back in and it would function.


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## Woodsmith (Jun 5, 2008)

That's the way I like to work too. Minimal damage or changes to stock so that modifications can be undone.

I deal with buildings and machinery alike as much as possible so that there is no lasting damage.

That is one reason why I am dithering over cutting the shaft off my 12" motor! Do I chop the motor or do I chop the car?
One just needs to weigh the 'least worst' compromise in these matters.


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## procupine14 (Mar 17, 2010)

Woodsmith said:


> That is one reason why I am dithering over cutting the shaft off my 12" motor! Do I chop the motor or do I chop the car?
> One just needs to weigh the 'least worst' compromise in these matters.


This is the same reason why my dad's 1966 Nova SS drag car is still only running 10" wide slicks because those are as big as it can go before you cut the trunk.


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## Jimdear2 (Oct 12, 2008)

Proc,

I guess in the end you have to make the decision.

Do you plan to retain the clutch and accessories drives? In other words just put an electric motor in the position the old ICE was then run the motor at constant speed and run the accessories off the main motor.

I would like to advise against it. To run both you would need a much bigger motor then what is needed to just run just the tractor. For myself I would use a small motor 2 to 4 hp continous at 3 to 4000 rpm and 24 volts then run 36 volts. You should be able to fit two good sized batteries under the seat at the rear and 1 in the front.

Instead of belt drive I would run a chain drive and run without a clutch. This way you only take power from the batteries when you are moving. You wont usually be shifting gears when you are moving anyway so on an electric tractor a clutch is redundant.

If you decide to keep the stock drive train and clutch you MUST install some kind of over rev protection. If you should break a belt, jump out of gear (a problem with cub transmissions I'm familiar with) push in the clutch or hang a wheel in the air you stand a chance of an over rev and expoded commutator. 

You should really have over rev protection on any drive method, It's just that direct drive has fewer things to break.

Just my opinions,
Jim


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## procupine14 (Mar 17, 2010)

Well Jim I highly respect your opinions that is for sure! I think that there will be definitely some form of over rev protection so I won't blow anything up if I break a belt. There have only been two belts on that tractor in its lifetime for the drive belt so either we get good ones or gatorback is a company I need stock in . But when the belt does break or a shear pin fails I need something to not break my stuff. 

I think as far as the clutch goes we will either just take it out or disconnect it at first and then take it out later (as in retain the clutch but just have it engaged all the time with no connection to the pedal. This will make it really easy since the clutch is basically brand new and if anyone ever wants to put it back to gas it won't have been molested . At least that is my initial plan. past that we are going to go through the brakes and retain those (of course) and put in either a pedal on the other side or wire the potentiometer to the original throttle cable. This would be nice in one regard because we can maintain a constant speed while moving without having to hold down the pedal 30 minutes to an hour which would be a major drag. We will see, I can see the major safety concerns with doing it this way but the plan will be that there will have to be a key on and a body-worn safety clip engaged to turn on the motor.


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## major (Apr 4, 2008)

procupine14 said:


> We will see, I can see the major safety concerns with doing it this way but the plan will be that there will have to be a key on and a body-worn safety clip engaged to turn on the motor.


Hey proc,

Most tractors have a seat switch. Just use that as an interlock (permissive signal). You need one on the brake also. Just wire the two switches in series and to the enable pin on the controller. Once that circuit breaks, from the seat or brake, you have to turn the throttle off before the motor will start again. It is called Static Return to Off, SRO. A feature on all Curtis controllers I used. And the throttle instead of the foot pedal is real nice 

major


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## procupine14 (Mar 17, 2010)

major said:


> Hey proc,
> 
> Most tractors have a seat switch. Just use that as an interlock (permissive signal). You need one on the brake also. Just wire the two switches in series and to the enable pin on the controller. Once that circuit breaks, from the seat or brake, you have to turn the throttle off before the motor will start again. It is called Static Return to Off, SRO. A feature on all Curtis controllers I used. And the throttle instead of the foot pedal is real nice
> 
> major


Good to know about the foot pedal! Well major, if you see how old this tractor is, there is NO seat switch or any safety feature on this tractor. That's why I need to have some other kind of safety switch. Either I need to retrofit a safety switch or some type of kill switch/wearable switch. Remember, this tractor is almost 50 years old


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## Twilly (Jan 22, 2008)

I am planning a conversion on a small rear engine snapper. I have been told that these Etek motors work great on lawnmowers because you can get away without a controller. Any one have any experience with these pancake motors?

Twilly


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