# Converting Riding Lawn Mower 2 Electric



## MarxNutz (Apr 5, 2008)

I was commenting in other threads about converting a riding lawn mower to electric. But then I figured I should just move to a new thread when I wanted to talk about my project, instead of throwing in my two cents in other people's threads.  I'm converting a Turf Pro 12.5 hp riding mower to a 36 volt 38 amp perm mag Leeson motor. I'm at the point where I'm about to get an adapter made to mate the 11/16" shaft of the Leeson to the 1" shaft of the drive pulley of the mower, and then mount the motor and try a first spin-up test with a 12 volt motorcycle battery. I wanted to know what would be the least expensive controller setup I could get away with this motor running @ 36 volts? And recommendations to where I can purchase the items needed for this setup?


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## enganear (Jun 16, 2008)

MarxNutz said:


> I was commenting in other threads about converting a riding lawn mower to electric. But then I figured I should just move to a new thread when I wanted to talk about my project, instead of throwing in my two cents in other people's threads.  I'm converting a Turf Pro 12.5 hp riding mower to a 36 volt 38 amp perm mag Leeson motor. I'm at the point where I'm about to get an adapter made to mate the 11/16" shaft of the Leeson to the 1" shaft of the drive pulley of the mower, and then mount the motor and try a first spin-up test with a 12 volt motorcycle battery. I wanted to know what would be the least expensive controller setup I could get away with this motor running @ 36 volts? And recommendations to where I can purchase the items needed for this setup?


The cheapest would be a contactor setup. If you use (6) 6V batteries, you could switch them to provide 6/18/36V without overstressing any one battery. Of course, if you have to use (3) 12V batteries, this would not work.
-enganear


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## MarxNutz (Apr 5, 2008)

I've figured out a way to get an adapter made to mate the electric motor to the dual drive pulley, which has been the stumbling block of this project...
I went to the local technical school and spoke with an instructor in the Machine Technology class. I showed him what I wanted done and sketched out what I thought it should look like. He made some measurements and a few suggestions, and told me it shouldn't be a problem to make, just may take a few weeks because of the class schedule. I thought 'Why didn't I just do this in the first place? I could be done already!'  Ah, live and learn... Moral of the story: Think about local resources for those little pieces of the project you may not be able to do yourself, and USE them!

P.S.: Can't wait for the adapter to be ready!


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## Shanex-2 (Jun 7, 2008)

I have also been contemplating doing a riding mower conversion the mower is a Craftsman 38" deck with a 10 hp briggs . As far as the speed controller goes have you thought of using an air governer system like what they use on small push mowers to control the carb except this is for an electric and would control a micro switch which would control a contacter turnig the motor on and off at a preset rpm .
My drawing is crude but I hope it gives the general idea.


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## xrotaryguy (Jul 26, 2007)

Shanex-2 said:


> I have also been contemplating doing a riding mower conversion the mower is a Craftsman 38" deck with a 10 hp briggs . As far as the speed controller goes have you thought of using an air governer system like what they use on small push mowers to control the carb except this is for an electric and would control a micro switch which would control a contacter turnig the motor on and off at a preset rpm .
> My drawing is crude but I hope it gives the general idea.


That's a neat idea. It's very simple. I like it.


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## MarxNutz (Apr 5, 2008)

Well, it looks like I will have a regular speed controller for my mower after all. My stepfather is building one which will handle up to 75 amps, more than enough for my 38 amp motor. Your idea sounds like it would work well. Please let me know how it works out.


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## Shanex-2 (Jun 7, 2008)

the only draw back to an air governer system would be the choppynes of its opperation but I will never know until I try it myself . They use a fly weight systems on the bigger I/C models and especialy on generators and would probably be easier to build then an electronic speed controler that would very pulse width depending on load condition.( I'm more mechanicly inclined then electronicly inclined but I'm learning) I hope your build goes well and will look forward to seeing it's progress. I will be posting my project as well as soon as I get some pics of it .
HAVE FUN WITH YOURS.


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## MarxNutz (Apr 5, 2008)

Awwwwwwwwwwwrighty then! I finally got that dern adapter made! The instructor who I originally asked to make the part transferred out and a new one came in. The new one was more than happy to help me out. I picked it up today, and it is a perfect fit! I would recommend any time you need a custom part made, pay a visit to your local community college, technical school or high school-level technical center. They like having these little projects to have their students work on. And they didn't charge me a penny! Check it out!


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## slawking (Jun 12, 2009)

I would recommend not using a controller, but just use a properly sized and rated contactor with an on/off foot switch. 

A controller will actually be changing the speed of not just the mower, but of the mower blades as well whenever you let up on the "gas" so to speak.

This is not good. You want your blades to spin at a constant velocity, othewise your grass will not mow evenly.

I know. I just finished my 38" Craftsman electric conversion and am very pleased with it. Unfortunately I have a controller that I no longer need.

Good Luck.


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## enganear (Jun 16, 2008)

Hi,
What kind of motor is this? Series wound, shunt wound?

If it is series wound you have to be careful. Full voltage across a series wound motor with no load will usually result in overspeed until the commutator blooms and takes the brush holder apart.

Shunt wound is ideal for switched operation (no controller) as are permanent magnet motors. They both operate a pretty fixed speed loaded or unloaded.

I am converting an old Murray to an electric lawn tractor (no mower) using a series wound motor at 36V and a controller. This winter I plan to convert my Lowes riding mower using an Etek PM motor at 48V and a switch.

See Murr-E at http://www.evalbum.com/2502

-enganear



MarxNutz said:


> Awwwwwwwwwwwrighty then! I finally got that dern adapter made! The instructor who I originally asked to make the part transferred out and a new one came in. The new one was more than happy to help me out. I picked it up today, and it is a perfect fit! I would recommend any time you need a custom part made, pay a visit to your local community college, technical school or high school-level technical center. They like having these little projects to have their students work on. And they didn't charge me a penny! Check it out!


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## slawking (Jun 12, 2009)

enganear said:


> Hi,
> What kind of motor is this? Series wound, shunt wound?
> 
> If it is series wound you have to be careful. Full voltage across a series wound motor with no load will usually result in overspeed until the commutator blooms and takes the brush holder apart.
> ...


I am using an ETEK-RT PM with 4 Optima D31 Yellow Tops at 48volts.

It has torque and power to spare.

Here is a link to a video of my first test drive (sans hood)

http://www.youtube.com/watch?v=GEam4PWM2AA


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## MarxNutz (Apr 5, 2008)

Well, long time no write! My wife and I bought a house this time last year, and we've spent most of our time and money putting our home into shape. About 2 weeks ago my wife says to me, "When are you going to get that old mower running?", which lit a fire under my ass . I finally got around to mounting the Leeson PM motor onto the mower and hard-wired a single lawn/garden battery (from my new ICE lawn tractor) to test it. I was pleased that the mower rolled along, even though it was slow as Christmas. So I added a second battery and voila!  I nearly snapped my neck at takeoff LOL! No, but seriously, it was much better acceleration and I can't wait to finish wiring a switch in and adding yet more batteries so I can take that booger out onto the pavement for some street testing!  A guy at my work gave me an electric push mower that didn't run and I found that the motor was destroyed. The batteries and circuitry was intact though, so I will strip all that off and add it to what I have already. I also have the original charger that came with that mower, so I can charge those two batteries on their own. My goal is to have enough speed and range to go to the nearest store and back.  (Don't worry, it's all residential streets and no highway crossing AND outside the city limits haha)


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## MarxNutz (Apr 5, 2008)

UPDATE: I have installed a battery box made from a large plastic tool box, with 3 lawn/garden batteries, so my tractor is running 36 volts. I road tested it today and got around 20 minutes of run time. I have a video on YouTube and a link from my EValbum listing (Mark's 1998 Turf Pro) of the last part of the test. I didn't bother with a controller, I just use the clutch to engage/disengage the motor to/from the transmission. It works just fine that way, as it "revs" up when I let out on the clutch. I can still also use the original 6 gears to help moderate the speed. It feels almost as if it's flying when I have it in 6th gear, even though I'm actually only doing about 10 mph lol! I'll have to use my cellphone's GPS to try to determine the actual speed. In the meantime, I suppose I need to start upgrading the batteries to something with more storage capacity, so I can get more range out of the tractor.


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## Woodsmith (Jun 5, 2008)

Well done!

The tool box idea is good, I may try that for my tractor. It would make a good way of having swapable battery packs especially if it were one of those tool boxes that have wheels at one end for easy trolleying.


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## Twilly (Jan 22, 2008)

Guys, I am converting a snapper rear engine rider to a 36 volt Etek motor without a controller. I have it running and the speed and power is great, but the one issue is I am turning it on and off with a 48 volt rated 100 amp circuit breaker and with no load the startup current is so high that it trips the CB almost immediately... I have to flip the CB multiple times to get the motor to start spinning, and then it will finally run... no load run current is 8 amps....

Do any of you "controllerless" guys have this issue? how are you starting your motors?

Thanks

Todd


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## major (Apr 4, 2008)

Twilly said:


> Guys, I am converting a snapper rear engine rider to a 36 volt Etek motor without a controller. I have it running and the speed and power is great, but the one issue is I am turning it on and off with a 48 volt rated 100 amp circuit breaker and with no load the startup current is so high that it trips the CB almost immediately... I have to flip the CB multiple times to get the motor to start spinning, and then it will finally run... no load run current is 8 amps....
> 
> Do any of you "controllerless" guys have this issue? how are you starting your motors?


Hi Todd,

First, I do not recommend your set up. It can be dangerous. Circuit breakers are not designed to function as you are using it and can possibly fail closed.

A power resistor can be used in series with the motor to limit starting current and then by-passed for the run condition.

Regards,

major


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## Twilly (Jan 22, 2008)

So your talking about 2 contactors, one with the resistor inline for starting than a second to take the resistor out of the circuit? I could still use the CB for protection? Might cost as much as a cheap controller.... Will a curtis golf cart controller run a prem mag motor?

Thanks for the quick reply


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## major (Apr 4, 2008)

Twilly said:


> So your talking about 2 contactors, one with the resistor inline for starting than a second to take the resistor out of the circuit? I could still use the CB for protection? Might cost as much as a cheap controller.... Will a curtis golf cart controller run a prem mag motor?


Yes, yes, yes, and yes  Qualifier---The PM motors I have used were not eTeks, so I cannot say for 100%.


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## MarxNutz (Apr 5, 2008)

UPDATE: I decided to drop the toolbox battery container so that I could get back to a more OEM look of the mower, so I fashioned a battery tray out of some angle iron and managed to mount it onto the frame with just enough clearance to put the hood back on. I also opted not to use a motor controller, just a heavy duty on/off switch from Advanced Auto and the clutch pedal to control speed. Works pretty good, although my runtime is pitiful with the lawn/garden batteries. And I won't spring for better ones until I have gotten my next project on the go. The mower is pretty much all done, and I have actually used it for hauling branches n stuff from the back yard. I have started on my next project, which is a motorcycle conversion using a Club Car 3.2 hp motor. BTW, here is a link to a test ride I took on the mower while the toolbox was still on the front of the frame: http://www.youtube.com/watch?v=qNVdMvdeNmA


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