Electric Riding Lawn Mower Conversion -- 24V

[majerus]

For awhile now I have been wanting to buy a riding electric lawn mower however didnt like the options on the market given their small size vs cost. After looking at options I decided to pull the trigger on a kit and give it a go.


$50 bucks donor Mower : Craftsman Riding Mower 42 Inch cut

Tear Down

Now time to mount the electric transaxle, this drives the unit forward. Also working on the battery tray. First attempt was a major failure as I cannot weld to save my life. After that occured I just bolted some flat steel plate and then with the help of my neighbor powder coated it chrome.

Failure

New idea!! Use bolts , give up the welding idea

Power coating, this was pretty awesome to do had no idea you could do chrome.

Electric PTO where the cutting deck plugs in.

Wiring from the kit, overall pretty straight forward however time consuming

I needed to 3d print a couple parts, first was a shim for the Voltage / Amp Guage. Went into tinkercad and mocked it up and fit perfectly. Also printed a knob for the temp speed control.

Cutting Deck, the holes in the deck were to small to fit the motors so I created a template from cardboard and marked the deck which needed to be removed. Cut that out and then fit the motors, which were too low so I used cutting board material to make shims. Overall seems to work ok, I plan to have a local fabricator create a metal shim for me this was just a mock up.

Overall still have a ton of work to do , want to polish it up and finish up making the wiring and overall product look better. I have cut very little with it so far (just got it moving a few days) I seem to keep tripping the cutting mower breakers for some reason still working though that issue. Probally something with my wiring.

 

[majerus]

Couple Videos

 

[alwaysFlOoReD]

Pretty damn cool!
Where did you get the kit? Link?

 

[majerus]

Thanks! Picked up the kit from https://www.electrictractor.net/, I tried in the past to do the plans only but had a hard time finding parts. The kit made things a bit easier for sure.

 

[mike93lx]

Pics aren't working for me

 

[laser3kw]

Pics aren't working for me

me either. Our security / firewall blocks certain websites including some photo sharing. I tried another method to view but I got the message "HTTP 403 - This website requires you to log in"

 

[kmacht]

I guess I have to ask. Why? The kit is $1300 to $1700 and doesnt even include batteries or other "commom" parts. You can buy a brand new gas mower for less than the kit.

 

[majerus]

me either. Our security / firewall blocks certain websites including some photo sharing. I tried another method to view but I got the message "HTTP 403 - This website requires you to log in"

Ran out of transactions on the hosting i was using should be fixed.

 

[majerus]

I guess I have to ask. Why? The kit is $1300 to $1700 and doesnt even include batteries or other "commom" parts. You can buy a brand new gas mower for less than the kit.

Honestly just because its neat. Also not a fan of gas in general. I have an electric car, tools, yard tools. My last hold out was the mower, then should be gas free other then my truck and boat. I think the kit ran 1200, could be off on that.

 

[theoldwizard1]

Those lead acid batteries are NOT going to have a long life ! "Engine starting" batteries are design to give very short, high current power, not sustained power for any period of time. You would be better off with TWO 6V golf cart batteries.

 

[majerus]

Those lead acid batteries are NOT going to have a long life ! "Engine starting" batteries are design to give very short, high current power, not sustained power for any period of time. You would be better off with TWO 6V golf cart batteries.

They are 4 6V golf cart batteries....

 

[Stuart in MN]

It will be interesting to see how well it works and what the range is. I remember there was an electric lawn tractor made back in the 1970s, the GE Elec-Trak; my college roommate's dad had one. I've seen quite a few electric push mowers but haven't paid much attention to electric lawn tractors, I suppose there are several manufacturers of them today?

 

[majerus]

It will be interesting to see how well it works and what the range is. I remember there was an electric lawn tractor made back in the 1970s, the GE Elec-Trak; my college roommate's dad had one. I've seen quite a few electric push mowers but haven't paid much attention to electric lawn tractors, I suppose there are several manufacturers of them today?

The Elec-Trak looks pretty cool, wish I could have found one. As of now I only know of two one is the Ryobi RM480e which is a bit smaller. It can mow up to about 2 acres. Then a Cub Cadet which i think was barley 1 acre. When I looked at the cub the dealer wasnt very friendly and said it was a POS so I stepped away from that pretty quickly.

 

[EOC_Jason]

Pretty Cool, can't wait to see more.

 

[u3b3rg33k]

if you weren't already in it with motors, I would've suggested you pick up motors from plug-in push mowers. they're actually 120V DC motors, as they use the motor as a generator for the braking system. watching craigslist might get them for free/cheap.

you get something with a lower bearing meant for occasional impacts, and could use pairs of 60V li-ion tool batteries in series.

 

[Rewind97]

Very interesting. Sub'd to see more.

 

[majerus]

Just mowed for the first time about 1 acre it took just under an hour. Still working though a motor issue on one of the cutter motors but other then that its now working great. Charge time was just over 12 hours on a 5 amp charger following the mowing, and driving around the yard with a trailer.

 

[GoodJobTim]

That's 240lbs of batteries!

 

[ddawg16]

Very cool

After about 2-3 years, start keeping an eye out for Li batteries. Much higher capacity and recharge time is more like 2 hours

 

[Boilerhouse]

My brother built an electric tractor - from a early 1970's John Deere that originally had a 10 hp Kohler. Did not use a kit, bought and scrounged parts individually. He has had it for at least 10 years now. I don't know if batteries are original, but I know I helped him replace the DC motor. Much like you, the reasons for building were a mixture of philosophy and challenge. He has a bit of acreage, and uses it to haul firewood out of the bush and the terrain back there is fairly rough, certainly no manicured trails. I have driven it a couple times, slow as heck, but surprisingly torquey.

 

[majerus]

That's 240lbs of batteries!

Just a bit over actually 272lbs :/

 

[majerus]

My brother built an electric tractor - from a early 1970's John Deere that originally had a 10 hp Kohler. Did not use a kit, bought and scrounged parts individually. He has had it for at least 10 years now. I don't know if batteries are original, but I know I helped him replace the DC motor. Much like you, the reasons for building were a mixture of philosophy and challenge. He has a bit of acreage, and uses it to haul firewood out of the bush and the terrain back there is fairly rough, certainly no manicured trails. I have driven it a couple times, slow as heck, but surprisingly torquey.

That is awesome happen to have any pics? Did he use one motor to run the pulley system I take it?

 

[majerus]

Very cool

After about 2-3 years, start keeping an eye out for Li batteries. Much higher capacity and recharge time is more like 2 hours

Yea, the only downside I would see there is that I would need a BMS, along with another charger. If I can get a old volt pack for very cheap I might try it. For now the lead acid batterys should be fine. Really this thing feels like a tank because of the weight.

 

[majerus]

For a bit of an update.. I was having issues tripping the breaker for the right cutter motor and noticed it was getting really hot while mowing. After talking to the company that sold the kit we determined that the blades I was using were to heavy. (Almost 1.5lbs each). Since I was having so many issues with the motor I decided to take the motor apart and noticed some of the windings were slightly burned, figuring this was not good I ordered a new motor. Personally, I think I just happened to get a junk motor since the other one was fine. Not wanting to run into any issues moving forward I ordered new much lighter blades from a Cub Cadet RZT S ZERO which were less than 1/2 the weight of the original blades. With the new blades it mows like a champ, sort of..

I put the new blades on fired it up and BAM! Both blades hit each other. At this point I was so pissed words cannot describe. When I ordered blades on eBay they listed them as 21”, however they really are like 21.183" which was enough to cause them to interfere with each other. To fix this problem I removed some material from each end of the blade and balanced them. Now its working without any problems.

Fixed:

Now that issues with the cutting part of the mower were solved I wanted to fix a few things I didn't like. The battery trays i build initially were only big enough to support about half the battery width. So, I tore the mower apart and and built new battery trays by welding two bent pieces of metal together. This supports the entire battery now and give me some piece of mind I won’t rub the battery to death.

The throttle was initially configured to just work by turning a knob on the dash. Overall this proved to be a pia, and not great when switching between forward and reverse, working around trees and hills that pop up when mowing. So I created a foot pedal by bending a piece of metal rod and shaping it with a wood template. Not really working with metal like this before was interesting. The foot pedal has a arm that is connected with a piece of metal attached to a gear box. I 3d printed the gears and messed with all sort of ratios starting at 4:1 (way to sensitive) and working down to 2.75:1. This really could probably work with 2.5:1 however for now it’s working so I will leave it as it is for a bit. The gears are connected to the potentiometer with a knurled set screw thing I was able to break out of a potentiometer knob. If anyone knows what this is officially called I would love to know.

Two springs work to center the pedal. This is working out well and was much better than one spring as I had it in the initial design.

This shows how the arm connects the setup is a little different this was the first attempt. I dont have a good pic for how it is now.

After mowing with three times now my average cost per charge is right at $0.12 for just under an acre. The charge time is just under 8 hours with my 5amp charger. This could go faster however higher-powered chargers got expensive very fast.


Pic from the smart plug for the charager.

Overall the mower is working pretty well, just hope it holds up. Working with metal was quite an experience and I now have a new appreciation for how things are built

 

[4EyedTurd]

Very cool, thanks for sharing!

 

[Fix Until Broke]

Nice project - You're welding has definitely improved

Do you grow you own (electricity)?

 

[majerus]

Nice project - You're welding has definitely improved

Do you grow you own (electricity)?

Still not great for sure, but had a boilermaker buddy show me some things which helped alot. Also the shade I was using before was way to dark so I couldn't see anything. As for electricity I am planning to install solar this summer which I'll probably do myself. The grass icon signifies lawn mower

 

[majerus]

The old Craftsman L frame after using the mower last year felt a bit weak. When I would go though a ditch, there was a really odd twist occuring that made me feel uneasy. So over this Corona Virus break I decided to rebuild the mower using a John Deer L120, and C Channel frame.

I have a 155C and generally liked it alot more then the Craftsman from a riding position, quality and overall looks, so the L120 seemed like a great donor mower.




First I gutted the Crafsman, and took out the wiring harness. Which was a complete mess it was not designed to be taken out after the install.




For the batteries to fit I had to weld in a new battery box in the rear of the tractor and remove the deck raise lever as it was in the way.



Additionally instead of cutting down the rims of the JohnDeere I needed to extend the axles. I bought some 3/4 round stock, and had a machine shop bore it out to 27/64's. I then tapped 12 x 1.25 threads and screwed it to the transaxle.








All the wiring was rebuilt using automotive style water tight connectors. Additionally I wrapped and grouped cables in loom which looks was nicer.








The old throttle I had setup on the craftsman worked fine, however it didnt feel smooth. This was one huge improvement. I decided to 3dprint the lever on to the gear. Removing the articulation point on the far edge of the throttle. Doing this helped so much its hard to explain. The Throttle and reverse work better imo then the original hydrostat does on a traditional mower now.






(This changed a bit when i got the deck on, used steel cable joiners instead of washers. Can see a better pic on the deck section)




Instead of trying to fit the John Deere deck with motors (it used 3 spindles and i only had two motors). I used the craftsman deck. To get this to work I had to weld a front bracket onto the mower for the front to attach. I then had to weld two brackets on the back to help keep the deck center. (also helps keep the deck form moving backwards when the front it connected) . For the raising and lowering of the deck I used steel rope.

I had to do this since I removed the original bar system that was on the tractor as it interfered with the batteries. Honestly this system works out really well, I am pretty happy with how it turned out.









You can see the bars I had to weld on the back of the frame. They connect to the flat stock that is attached to the frame.




Better located motor controller.



Mower Controller LED Status Indicator.


On my first mow things were going great then I tried to make a turn and the front wheel fell off. Not sure what happened, figured my rear wheel would fall off before the front would. Either way found a new C clip and was back to mowing.




Overall I need to button some stuff up.. but the mower mows way better and feels nicer. I was able to get the motor controller to increase power by 20% so top speed is a bit faster then my old gas mower. The plan it so not touch it for a few weeks mowand see how it holds up. if everything is great Ill tie up some of the loose wiring with zip ties, and then use it for a year. Next winter I plan to paint it and find a new hood. Never would have thought I would keep building lawn mowers

 

[Mark_17]

Very cool, thanks for sharing

 

[majerus]

Sadly the transaxle broke on this mower, and had to go out an buy a new one. Planning to fix it and use a real lawnmower transaxle and a pully drive system. For now I bought at Cub Cadet LT42e.. Its kinda neat, and interesting to see how similar the two machines are, i did a quick review if anyone is interested in it.

 

[acer66]

Very cool, thanks for sharing

Yes.

 

[JDelectrictractor]

Hey Majerus I did the same conversion on a John Deere and now have broke 2 of the same gears in the transaxle. I only get about 15 times mowing a 1/2 acre lot out with it Last year I pulled a lawn sweeper and other attachments. But they told me that this kit is for mowing only so after replacing transaxle this year I didn't pull anything and it still broke after about 15 mows. It might be the weight is higher on a John Deere. Other than that this tractor works great!

 

[majerus]

Hey, just saw your reply going to send you a private message.

 

[48windsor]

It will be interesting to see how well it works and what the range is. I remember there was an electric lawn tractor made back in the 1970s, the GE Elec-Trak; my college roommate's dad had one. I've seen quite a few electric push mowers but haven't paid much attention to electric lawn tractors, I suppose there are several manufacturers of them today?

Yes there are . Im interested in one. Ryobi makes one. waiting for reviews

 

[theking]

I just found this, I would love to take on a project like this some day.

 

[majerus]

Yes there are . Im interested in one. Ryobi makes one. waiting for reviews

The ryobi mower has a lead acid battery, I would suggest making sure whatever you buy is lithium it will age batter and has zero maintenance.

 

[48windsor]

Thank you Majerus

 

[Thirdyfivepickup]

very cool post! I push mow with a battery powered mower and love it!

 

[White Shadow]

This reminds me of my neighbor, who had an electric riding mower back in the 70s when I was just a little kid. His electric riding mower was from Sears, but I'm not sure who made it. I remember it had a bunch of lead-acid car batteries under the hood though.

 

[White Shadow]

The ryobi mower has a lead acid battery, I would suggest making sure whatever you buy is lithium it will age batter and has zero maintenance.

I considered buying the Ryobi zero turn. They do use lead-acid batteries and they are supposed to be able to cut more than 3 acres on a single charge. Now they even have a 54" version which is pretty nice for big yards.

The batteries are supposed to last for at least 7 years before they start to lose a significant amount of capacity. And if you're only cutting an acre or two, then you'll probably get a lot more than 7 years out of them. Ironically, when you factor in the price of replacement batteries versus the cost for the gas you'd use to cut the same size lawn for 7 years, it pretty much breaks even. I did that calculations on my own property. The only real advantage of the electric mower was the lower cost of maintenance over time. But then again, it doesn't cost all that much to maintain a gas mower either.