DIY Electric Tractor: Page 2 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

STEP BY STEP

1. REMOVE THE GASOLINE ENGINE

Remove all gasoline-related parts—the motor, control cables, wiring, and fuel tank. Keep what you can in serviceable condition—you may be able to sell the parts. Save the drive mechanism—whatever is attached to the output shaft of the motor (including the pulley).

2. CLEAN THE TRACTOR

Your EV will operate without making a greasy mess, so take the opportunity to clean everything now. It’s up to you if you want to spend time repainting or finishing the old tractor, but getting it clean makes working on it more pleasant.

3. LAY OUT THE PARTS

Check out the space that’s available and try laying out your parts in the chassis. The belt drive requires mounting the motor in the same spot as the gas engine. Finding the best placement for your batteries and controls can take some experimentation.

4. MOUNT THE MOTOR & BATTERIES

Mounting the motor requires drilling a 1/4-inch-thick aluminum plate with a center hole for the output shaft, four holes for the motor, and four holes that line up with the existing holes in the chassis. This doesn’t have to be precise or pretty—you can use scrap plate if you have it. Use bolts with washers and lock washers to secure the motor.

A new V-belt drive pulley, similar to the original, will be used. Be sure to match it to the shaft diameter of the electric motor. Since we’re running a motor that will develop roughly the same rpm as the gas engine, using the same diameter pulley will keep speeds about the same as original.

The four sealed lead-acid batteries fit inside a plastic battery tray that was purchased at an auto parts store, and it happened to slide right into a space at the front of the chassis. If you’re not so lucky, it may take some effort to figure out the battery placement, especially if the batteries are larger or more numerous. Regardless of where they are placed:

  • Mount the batteries securely. It’s vital that they do not shift and tip, especially if they’re flooded batteries. Many DIYers will build robust battery boxes or racks made from angle iron or aluminum sheet. 
  • Isolate the battery compartment, if possible. Plastic battery boxes are ideal, both as electrical insulators and to contain electrolyte spills.
  • When making electrical connections or just placing the batteries in the chassis, keep in mind that you’re dealing with potentially lethal current. Use insulated tools (or insulate yours by wrapping them with electrical tape), and double-check every effort. If you have any doubts about making a connection, check it with a voltmeter first to verify that you’re about to do what you think you’re about to do. We call unintentional arcing “plasma events,” and they’re dangerous.

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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