DIY Electric Tractor: Page 4 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

The Continuing Project

From the testing, it was clear the tractor will be a productive tool around the grounds. We decided an investment in the purpose-built Motenergy would be worthwhile. The 48 V, permanent-magnet DC motor with a 1-inch shaft will have enough power for the stacked pulley that also drives the mower deck. However, the bigger motor will work well within its load range and will heat up less, and will be more efficient.

Switching the two motors was a matter of unbolting the first one and using the same mounting plate for the new motor. Both motors have a standard NEMA C bolt pattern, so the holes matched up perfectly—and the cable attachment was also a match. Then all we needed to do was remount the mower deck.

This is a great example of building a balanced system. When the tractor had the small motor, small batteries, and a relatively light load, it provided good power and range. Once we increased the motor size, we could add more load, like the mower deck. However, the batteries were not up to the task. Monitoring how much “mowing range” the original batteries provided gave us an understanding for how we’d need to upgrade. The smaller batteries let us mow just barely a quarter-acre, if they had a full charge and we were careful not to waste energy.  Increasing the battery capacity to four quality small, flooded lead-acid automotive batteries in the 40 to 60 Ah range was necessary to get an acceptable mowing range of our quarter-acre lawn, with a little extra for insurance. A nearby salvage yard sells used batteries for $35 each. Even better would be to use 12 V deep-cycle batteries, similar to those intended for golf carts.

What will come after that? Adding function is simply a matter of adding another motor, so there are many options: a power take-off, hydraulics, etc. For now, though, it looks like the resident teenager has a lawn to mow!

Access

Ted Dillard has been an avid gardener since childhood and is an evangelist for all things electric. He writes The Electric Chronicles (devoted to two-wheeled electric vehicles), and is the author of ...from Fossils to Flux, a basic guide to building an electric motorcycle. When he’s not in his garden or in his shop working on his next electric project, he can be found at evmc2.com.

Suppliers (Parts & Kits):

Electric Motorsport • electricmotorsport.com

EV Drives • evdrives.com

Motenergy • motenergy.com • Permanent magnet motor

Thunderstruck Motors • thunderstruck-ev.com

Comments (2)

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!

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