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Daox 11-03-08 08:41 AM

EcoRider - riding lawn mower electric conversion
Well, the time has come for my first EV project! I really wanted to convert the Toyota Paseo I picked up a while ago, but it would have cost too much for me at the moment. So, my next thought was that I really could use a riding mower. I have push mowed my lawn, and it takes a long time. So, I talked things over with Ben Nelson and MetroMPG, the two EV guys I know and decided to go with an electric riding mower.

This weekend I picked up a Simplicity 728 (no idea what year) from a very kind gentleman. I found and got the mower for free using It currently has a mildly used 8hp Briggs engine in it. The deal with the donator was that I take the engine out and return it to him since it hasn't seen much use. I was all too happy to oblige! So, now I have a new project for this winter. Hopefully updates will come fast. :)

For future reference:

Belt size:
Drive: L485
Mower deck: L478
Mower blades: L470
Snow blower: L482

cmittle 11-03-08 10:54 AM

This sounds like fun. I'm interested to see how everything goes for you to see what I can apply to my electric push mower conversion that I hope to have finished before spring. Be sure to take a lot of pictures!

insaneintenti0n 11-03-08 12:22 PM

that's awesome. have fun with that :)

sell me the Paseo while you're at it ;)

toyobug 11-06-08 08:51 AM

Daox- this is GREAT news for me. When I first stumbled upon Ecomodder, I wanted to build an Electric Motorcycle once my tour in Iraq is over. I figured it would be a good way to understand all the work and components required to build an EV. After further thought I decided that an electric rider would be better, (less chance of injury :) )
Now that you've got a project like this, I will be following along closely. Please take pics, and If I can help with researching info please let me know. Not that I could compare to Ben or MetrMPG, those guys are awesome!
I can't wait to see the progress!

Daox 11-06-08 09:43 AM

Well, I took the mower out for a spin last night. I really needed to cut the grass and chew up the leaves. So, the mower got its last run on gasoline. It worked quite well for what I seemed to think of as a small mower (only 8 hp).

I'm now starting to track down the necessary other items for the conversion. Ben Nelson said he would donate a few things so I'm really psyched about that! There will be many pictures to come. :)

Tony Raine 11-06-08 11:58 AM

cool idea! what kind of range do you think you'll get?

Daox 11-06-08 01:15 PM

1 Attachment(s)
I'm going to start with humble targets. I'd like to be able to mow half of my yard on one charge. Below is a pic of the two 'halfs'. I actually think, depending on the quality of the batteries, that I should be able to do the entire yard. However, I'll be fine if I can't do the entire thing all at once.

Tango Charlie 11-15-08 10:13 PM

Wow, Tim, that's a really nice spread you got there. Is the white structure by the cul-de-sac yours, too?
I am also very excited to see your rider conversion as it progresses. I have been thinking about doing the same, but have not committed to it...yet.
And yes, post lots and lots of pictures! :thumbup:

toyobug 11-16-08 10:57 AM

any progress on the mower Daox?

MetroMPG 11-16-08 07:23 PM

Yes: I reneged on a free motor controller I offered to send Tim.

OK, technically Ivan reneged, since it's half his I suppose. Sorry!

Daox 11-17-08 08:14 AM

Nothing yet, I've been spending most of the time on the house still. I'm finally getting close to being done with the attic.

As for whats been happening with the mower, not a ton. I'm still searching out parts and thinking up how everything is gonna get done. I'm pretty sure I have a motor and wiring for it. I'm still debating on weather to go with a controller, or not too. I've seen a few on evalbum that don't, but I'm not sure how I'd set it up yet.

Thanks Terry. Yes, I do own the white building on the end of the cul-de-sac. Thats my garage.

toyobug 11-19-08 09:56 AM

guess you'll have a good winter project once you get the insulation finished up

bennelson 12-17-08 07:40 PM

I have three different motors out of a forklift at my house. I also have plenty of welding cable and a few contactors and fuses.

If we dig up a golf cart controller, the only other thing we would need is the batteries.

I think a two-motor approach might be best. Have one motor run the wheels of the mower (controlled by a golf cart controller) and another that powers the blades (turned on and off with a contactor).

This is similar to how an Electrak works, except that it had a motor for each individual blade.

Alternatively, we could hook up a couple of reel mowers behind my Citicar....

jwxr7 12-18-08 11:24 AM

that 728 you are going to convert looks identical to mine. Although I think mine is a 738 simplicity. Something must be different, but mine is also an 8hp. It has a three blade deck that cuts about a 36" path. It's interesting how they articulate back near the seat, instead of the front axle. I've had it for around 10 yrs and it's been a workhorse. I actually plow my driveway with it. It has a 42 or 46" snow blade I put on in the winter along with tire chains.

good luck with the conversion.

Daox 02-01-09 09:28 PM

It finally got tropically warm (35 degrees) this weekend, and with my insulation project behind me I took some time to do some work on the EcoRider. The first step? Rip out the engine! The previous owner is still patiently waiting for me to return it thankfully.

I also got a chance to talk with an elec-trak owner at an EV meet. He said the Elec-traks can do about 2 acres of mowing before they need to be recharged. So, with my less than an acre to mow, I'm not going to worry at all about not having enough battery capacity.

Now pics!

Pulled the top cover off.

Front cover off.

Yay, the happy moment of draining the last bit of gas this mower will ever see.

Engine GONE!

jwxr7 02-02-09 06:47 AM


That tractor looks like it's in way better shape than mine.

gascort 02-17-09 02:24 PM

Neat project - I look forward to seeing how it goes!
Ben - the CitiMower is a great idea!!!

Daox 02-19-09 08:53 AM

Got a great update here. This past weekend I was at a build day for EVs that goes on in Milwaukee. The host runs a recycling business and got me 24 7Ah 12V deep cycle batteries for the mower. This will allow me to run almost any combination of voltage I want. Then, last night I met him at his warehouse. We dug through some stuff and we found a 1.6hp 24V motor that I think will be pretty ideal for my setup. I was hoping for a 2hp, but this will probably be fine. In addition to the motor I also got a few contactors, some nice heavy gauge wire, and even a forklift motor controller if I end up needing it. This is nearly everything that I'll need to complete the mower!!! I'll post pictures of it all tonight.

jwxr7 02-19-09 09:25 AM

That is awesome :thumbup:. Nice to have a contact like him.

Daox 02-19-09 09:59 AM

Yeah, he is a great guy to have around. However, it also makes me realize, you could probably do the same with your local recycling place. Give them a call once a week and see if they have any electric parts if you are looking. Chances are that you can probably pick up parts for next to nothing. All they're going to do is rip stuff apart and sell it as scrap metal.

bennelson 02-19-09 10:11 AM

Hey Tim,

Make sure to post some pictures of your loot so we can see what you got!

My goal for the year is to get off gasoline, and that includes mowing lawns.

Reel mowers behind the Citicar keeps getting more intruiging.

Daox 02-19-09 10:15 AM

I've really been slacking in the pictures department. I meant to post about the batteries early this week and didn't even pull them out of my car until mid this week. Oh yeah, the batteries came with nice trays even!

Daox 02-20-09 06:14 AM

5 Attachment(s)
Alright, here is what I all got.

Motor, controller (top), wires, potbox and contactors in the bin.

Motor tag and ratings. I'm glad its rated for more than 1700 rpm.

The motor has two extra wires comming out of it. Tom thought this was probably either for a temperature sensor or rpm output.

The removable foot mount. I think I'm going to take it off and try to face mount it. There are no tapped holes in the end, so I'll have to disassemble the motor and drill and tap some holes.

Its just about 7 inches in diameter.

Daox 02-20-09 06:18 AM

5 Attachment(s)
The motor looks just over 8 inches long.

Here we have the box of contactors.

And here we have the fork lift controller and pot box.

Of course I couldn't resist a trial fit. :D

These are the batteries I got. They're about half the size of a motorcycle battery and are rated at 7 Ah.

Daox 02-20-09 06:21 AM

1 Attachment(s)
The batteries even came with these nice battery trays.

That about does it for parts. The next step will be finding pulleys for it. The two shaft extensions are different diameters, so we'll see which one its easier to find pulleys for. I've was told I can go down to the local farm supply place and pickup hubs that you just bolt different size pulleys to, so I'll probably try that out. After I have that sorted, I'll look at mounting the motor.

MetroMPG 02-20-09 08:25 AM

Nice haul! Christmas came early (or late) for the project.

Daox 02-20-09 03:12 PM

While we're at it. Anyone got some good suggestions on color schemes? I kinda like the Simplicity colors, but I'm open to suggestions.

Higgy 02-20-09 08:45 PM

You strike me as someone who flower decals.


davidbr13 02-25-09 10:45 AM

That's awesome! Haven't been around here for a while, but just dropped back in to ecorenovator and found this cool project. Gotta say finding a motor is the hardest part. If the one you have is permanent magnet, don't bother with a controller. Use a contactor and continue to use the transmission to change the ground speed. You'll just have to change voltage and/or pulley and belt sizes to get the same speed the Briggs had.

I've finally resigned to sandblasting my E15 elec-trak "basket case" myself and using regular paint (powder coating shops around here cost 3-10 times what they do in the rest of the country). I've got most of the parts, but have a LONG ways to go...I am trying to put together a restoration album, though.

Daox 02-27-09 08:08 AM

4 Attachment(s)
Last night it was a bit warmer out and I took some time to work on the mower.

The first thing I did was take the motor apart. I want to drill and tap the face of the motor so I can just mount it flat against the mower frame. So, I needed to know if there would be enough material to screw into, and if the screws could protrude into the motor at all without hitting anything. The picture shows the flange that will be facing downward. I didn't measure the exact thickness, but it should be just fine.

The motor housing and brushes also looked in good shape. There appears to be plenty of meat left on the brushes. It also seems to be fairly clean.

Daox 02-27-09 08:21 AM

4 Attachment(s)
I also took some time to fiddle around with the mower itself. First off, I removed the gas tank. We definitely don't be needing that anymore. :) I also removed the starter solenoid that you see in the pictures.

After removing those bits, I marked where the motor will sit, and played around with how the batteries will sit into the mower. You would think with all those smaller batteries that it would be easier to find places for them. Well, you might be wrong. The mower isn't really all that big. But, I think I have found places for all 24 batteries.

bennelson 02-27-09 09:49 AM

The commutator and brushes on your motor look great!

Having a tail-shaft is nice too. It opens up some possibilities. I wouldn't have been able to do a home-brew coupler the way I did without the tailshaft on my motor.

As for color scheme - gloss black with neon green lightning bolts! :thumbup:

Rich's nephew, Tom, who was out at the last EV build day also wants to build a n EV riding lawn mower. You will have to talk with him if you make it out to this weeks build.

Daox 02-28-09 12:58 PM

I'm keeping at it. This morning I drilled and tapped the holes in the end of the motor and reassembled it.

I printed out a template to help with the drilling. That pattern isn't exactly centered on the motor, but there really aren't any alignment requirements since the motor just has belts going to it. This really simplifies things.

I decided on a 6 bolt pattern since the casting wasn't quite as thick as I had hoped, and I also went with 3/8-24 (fine thread) tapped holes to give it extra holding power. This is probably overkill, but its a lot easier to drill and tap two more holes than it is to fix a problem later on.

I drilled pilot holes first with the template to get things started.

My battery drill battery ended up dying on me after the first two holes. Waiting for it to charge, I went ahead and tapped the holes.

A little while longer, the battery was done recharging (yay for fast charge lithium) and I popped the rest of the holes in and tapped them as well.

And, finally I reassembled the motor.

I also ran to the local bearing supply company and picked up two pullies. Since the motor is rated at 3200 rpm I'm guessing I won't be way too far off going with slightly larger pullies. I'm guessing the gas engine spun around 3000-3500 rpm. If I'm way off, I can always get new pullies.

The one problem I may have to find a fix for is the drive pulley. The stock one has no hub on the side and is much thinner. I'm not sure how both of the pullies will fit on the motor shaft. If worst comes to worst I'll simply chop off the hub, and drill and tap a set screw hole in the middle of the V like the stock pulley.

Daox 03-05-09 09:27 PM

I've been working on the battery racks for the past few days. Its is going to take a while since there are 24 batteries! I started with the back end. I wanted to get as many in the rear as I could to free up space in the front of the mower. I was only able to get 6 in the back, but thats 6 less I need to find space for up front.

This rack will hold four batteries. The one on the other side will only be able to hold two.

I'll make some sort of clamping mechanism to hold the batteries solidly. Also, another piece of angle will be welded above it for the additional two batteries.

MetroMPG 03-06-09 07:04 AM

Cool - another update. Watching with interest.

Daox 03-17-09 02:48 PM

I haven't had a chance to do any real work on the mower unfortunately. However, I have been looking at what else I'll need to have once I get the batteries mounted.

First off, I setup one of my contactors to operate off the stock key/switch. So, that will remain on the mower and be my on/off switch. It even has a momentary setting for starting the gas engine. Perhaps I'll use it as a soft start if need be.

I also got an ammeter from Ben Nelson. It is rated to 200A which I hope will be way more than I need. I figure if I'm pulling 100A constantly I'm going to have about 45 minutes of run time. I'd like to have a bit more than that. I don't remember exactly how long it took to cut the grass before, but 45 minutes is probably cutting it close.

I've also been looking at voltmeters for the mower. Something like this would be nice. However, I'm also looking into a way to monitor each battery so I know if there is a weak one. If I don't monitor them all individually, I'm bound to have problems with killing batteries. So, I googled and found this tutorial on how to make cheap battery monitors. Unless I get some bad feedback on this design, I'll probably go ahead and make one for the mower. 24 LEDs will light up, as soon as one battery's voltage drops too low, the light goes out and I know its time to bring the mower in. It will also allow me to find that bad battery and replace it if need be.

Higgy 03-17-09 03:37 PM

I'm tellin need to make it look like a time machine from the 50's B movies.

Daox 03-23-09 09:12 AM

For reasons of documentation I am putting this here. :) The on/off contactor I'm planning on using for the mower pulls .8A @ 12V. This is less than I had heard they pull.

Daox 05-04-09 02:04 PM

Well, progress on this project has been stopped cold in its tracks. I've been too busy fixing other things and what not and just haven't had time to work on it. Of course, now its spring and the grass is starting to grow and I want to use it. The battery mount progression on the mower has been horrible and I don't have much done at all. So, I'm really thinking about trying to get some larger used deep cycle batteries from the local truck repair place or forklift repair place. That way I would only need to mount three batteries. I'll be stopping by the truck place this week to see if I can scrounge up some batteries.

Daox 05-18-09 09:18 AM

Well, no luck at the truck stop unfortunately. I guess semis don't use deep cycles, but just normal starting batteries. I did get the number of their battery supplier though, and it looks like they deal in anything and everything battery related.

In the mean time, I have gotten the motor mostly mounted to the chassis. I'm going to rig up some regular starting batteries I have laying around and go for a short ride to see how many amps the mower pulls in action. This should give me a really good idea of how much capacity the battery pack will need. Pics to follow soon!

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