DIY Electric Tractor: Page 3 of 4

Intermediate

Inside this Article

The newly converted tractor
The newly converted tractor earns its keep by hauling a load of firewood.
The original donor tractor.
The original donor tractor.
Power switch
Power switch
SOC meter
SOC meter
2-amp charger
2-amp charger
Main contactor
Main contactor
Before the engine removal and cleanup.
Before the engine removal and cleanup.
After the engine removal and cleanup
After the engine removal and cleanup. Note the new holes drilled for the motor adapter plate.
Test the possible configurations
Before installing the final motor and batteries, test the possible configurations to see which ones work best for your tractor.
The motor and batteries are placed and preliminary connections made.
The motor and batteries are placed and preliminary connections made.
The new controls
The voltmeter, power switch, and charger input receptacle—all conveniently mounted on the dashboard.
The fuse and contactor are mounted behind the dashboard
The fuse and contactor are mounted behind the dashboard on a cross-brace.
The converted tractor
The converted tractor with the upgraded motor and mower deck, operated by the author’s son, Tyler Dillard.
The new Motenergy ME1004 with the stacked pulley in place.
The new Motenergy ME1004 with the stacked pulley in place.
The updated tractor, with the Motenergy motor and mower deck
The updated tractor, with the Motenergy motor and mower deck, awaiting its new batteries.
The newly converted tractor
The original donor tractor.
Power switch
SOC meter
2-amp charger
Main contactor
Before the engine removal and cleanup.
After the engine removal and cleanup
Test the possible configurations
The motor and batteries are placed and preliminary connections made.
The new controls
The fuse and contactor are mounted behind the dashboard
The converted tractor
The new Motenergy ME1004 with the stacked pulley in place.
The updated tractor, with the Motenergy motor and mower deck

5. MOUNT THE CONTROLS

We opted for simple, yet safe and serviceable, controls. Don’t put the controls together in a haphazard way, since they are handling large amounts of current. Mount them safely and securely, and tape or put heat-shrink tubing on exposed conductors. You can take care of the cosmetic details like faceplates and labels later.

6. MAKE THE ELECTRICAL CONNECTIONS

Once again, lay out your parts and wiring before making the connections. Keep your basic wiring diagram at hand to avoid mistakes from lapses of attention or simple circuit errors.

It’s helpful if the diagram’s components are roughly in the same relative location as on the tractor. This makes it a lot easier to visually plan and check your configuration, and avoid errors (and plasma events). Again, test connections with a voltmeter if you have any doubts.

We used 4 AWG welding cable with crimped lugs, which are available from most welding suppliers, and insulated the lugs with heat-shrink tubing. Though there’s some debate over the advantages of soldered, crimped, or solder-and-crimp connections, any of the three methods will work well when done correctly. Pre-made cables are available from renewable energy retailers and some auto supply sources.

7. THE FRANKENSTEIN RUN

The “Frankenstein run” refers to the point at which everything is safely wired and ready to run, but a lot of the details are not complete. Besides being a thrill to see your creation take life, it’s also helpful for sorting out problems. It saves a lot of time if you can test before worrying about all the extraneous details. Before flipping the “on” switch, make sure that the vehicle is safe for a short test run—that batteries are secure, connections are insulated, and there are no loose wires or bolts.

8. FINAL CLEANUP & LAYOUT

Once you can see how the tractor’s working, go through each part of the system and double-check everything—mounting hardware, connections, insulation, tie-downs, and the rest. It’s possible to have moved through the main steps, leaving the details for later and then to have forgotten about them. Give all your connections one last check. A loose connection will arc, heat, and ultimately burn once you give it a load.

9. GOING TO WORK

Next, see what your EV tractor can do. We had a quarter-cord of oak sitting on the wrong side of the property, so we charged the batteries, mounted a ball to the trailer hitch, and hooked up the trailer. With the tractor’s transmission in low gear, we pulled the trailer from the low, back section of the property around to the front, up a slight grade, and around to the wood pile with nary a hiccup. Often a motor will heat up under strain like that, but even our “beta” motor was cool to the touch. The batteries had plenty of juice and the test was a resounding success. Later, we took the tractor to the neighbors’—about a quarter-mile away—in fourth gear with nothing in tow, and got back with just enough energy to pull up to the charger.

Comments (4)

Little Eddie's picture

Converting to battery power is a great idea for a garden tractor I converted one 15yrs ago and it is still cutting grass on a daily basis, I have had to renew the batteries every 7 yrs I am just on my 3rd set now, my design will cut up to 2 acres on a 50cent charge there are no belts or pulleys and no oil on the entire tractor, it can pull a trailer for about 8hrs on a charge, because battery run time is the most important aspect of most conversions I paid particular attention to the most efficient design I could up with, I used 3 separate small motors one for the drive with electronic speed control and two smaller with a cutter blade mounted on the shaft for each cutter, this design only uses the battery power req to do the job, very little wasted battery power, it uses magnetic breaking of both tractor and cutter blades and automatically applies parking brake when you stop or get off the seat.
Little Eddie Edmond Electric

SRland's picture

I love this project.

Rayzer's picture

This is pretty cool! I do have a few questions though;

1) How well do these electric motors stand up to all the dust from mowing, are they sealed?

2) What would it take to extend the mowing time to an acre, more or bigger batteries?

3) Would a bigger HP motor help with heat build up?

4) What would be the pros and cons of using a brushless motor instead of a brushed motor?

5) Have any cost comparison been done to see the difference between buying gas and the electricity used to charge this?

As you can probably see from my questions, I am completely ignorant on this subject. Great article, thanks I enjoyed it!

Little Eddie's picture

I can answer some of your questions,
1, I use sealed permanent magnet brush type motors, these stand up very well because they are sealed also reasonable price
2, This is the biggest challenge with any battery powered equip, Use the most efficient design you can afford, I can get 2 acres cutting or 8hrs pulling trailer per 50cent charge, 4 x 12v 120ah batteries in series 48v system
3, No! the smallest motor that can do the job is the most efficient, electric motors can be overloaded at least 3 times there rated HP for short times without damage, e,g pulling up hill etc, with an efficient design it takes very little power to move a lawn tractor across level grass,
4, Brushless motors are slightly more efficient than Permanent magnet motors but they require an electronic controller to run each one, the extra cost is not really worth gain in efficiency unless you can get a deal?
5, Yes my edmond tractor uses about 1/20 of the energy that a comparable gas tractor uses,so even if the electricity is generated by coal I use much less of it and much less pollution, depending on allot of factors I believe it takes anywhere from 4 to 8 ltrs of gas per acre with a gas tractor or only about 25cents 2KWH of electric per acre with my electric tractor.
Little Eddie Edmond Electric

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