How to Convert Your Gas Lawn Mower to a Solar-Powered, Grass-Cutting Machine

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With a few parts, a free weekend and a little DIY know how, you can convert your lawnmower from gas to solar powered (Photo: Lee / BuildItSolar.com)

Still using a gas powered lawnmower? Come on, this is 2012… we’ve got electric cars, solar panels on our homes, and giant windmills turning wind into power. Everything runs off electricity now, your mower should too.

And there’s no need to increase your utility bill just to tend to your yard… the sun helps grow your grass, it should contribute the power to cut it. Don’t just make your mower electric, make it solar too. Another bonus? It’s virtually silent. You can cut the grass and listen to the game at the same time.

A ordinary lawnmower before its convertion to solar (Photo: Guy Mardsen / Arttec.net)

All you need to convert your gas-guzzling mower into a sun sipping, solar, electric, grass-cutting machine is a free weekend, a few easy-to-find parts, and a little DIY know how. For that know how, we turned to three guys who have tackled the conversion with success: Guy Mardsen from Art-Tec, an electrical engineer and veteran converter, Lee who did his conversion five years ago and hasn’t used a drop of fuel since, and Jeremy James, who did his conversion as a project when he was an engineering student.

Here’s how to go solar:

1. Get the Supplies

You’ll need:

  • Lawnmower (It doesn’t even need to be working, so you can scour junk shops for a cheap one.)
  • Electric motor (Great guide to choosing one from Jeremy, here. )
  • 12 volt battery
  • Solar panel
  • Power switch
  • Battery level gauge (optional)
  • Electrical wire
  • Nuts, bolts and other hardware

[IMPORTANT: Before you start, make sure all the fuel is drained from the mower.]

2. Remove the Old Motor

 

This should be as easy as removing the bolts holding it on. But before removing the motor, Guy recommends measuring the blade height from the bottom of the base, and keeping detailed notes on blade height and the blade mount. This will help when reattaching the blade, or in case you need to buy a new blade.

3. Mount the New Motor

 

Bolt the new electric motor to the mower. Check the height of the motor, and use spacers to adjust the height if necessary. (For more details on making spacers, see Guy’s guide, here.) It’s important to make sure the motor is centered and bolted securely to the deck.

4. Reattach the Blade

 

Bolt the blade to the electric motor. This may be more involved, since you’ve got a new motor on the mower. You may have to get new bolts and bushings. (Details on what to do if you run into this here and here.)

Again, it’s important to make sure the blade is centered. An off center blade can cause vibrations which will shorten the life of your mower.

5. Add a Switch and Gauges

You’ll need a way to turn the motor on and off. A 60A 12V switch from an industrial electric supplier will do the trick. Want to know the battery level? Add a battery state gauge. Lee mounted a voltmeter to tell him when to quit mowing, and an ammeter to let him know how hard the motor is working. You can find gauges at an auto parts store.

The wiring for the gauges on Guy's mower (Photo: Guy Mardsen / Arttec.net)

A good place to mount the switch and gauges is on the handle, and you can do that by making a bracket out of a piece of aluminum, or a simple wood frame, like Lee made. for his mower.

[The wiring for the switch and gauges can be tricky, and will depend on the parts you use, and other factors. You can find a sample wiring diagram from Jeremy here.]

6. Mount the Battery

You should have enough room on the top of the deck to mount your battery. You can create a bracket out of angled aluminum to hold it in place. A good tip is to mount it over the rear wheels, letting them support the weight, and allowing the handle to serve as a lever.

7. Build the Solar Panel Recharging Station

Solar panels can be pricey, so set your sights on a used one from a second hand supply company or on eBay.  It’s a good idea to wire the solar charger to a charge controller. Guy says, “If you connect your solar panels directly to the battery, you will over charge it and ruin it.” The charge controller prevents this.

Mount the solar panels to a piece of wood for a movable charging station (Photo: Jeremy James)

Pick a spot in your yard that gets a good amount of direct sunlight, like the roof of your tool shed, or create a portable solar charging station by mounting the panels on some wood that you can move around the yard, depending on the time of year.

Will it take some time and planning to turn your outdated fuel-powered mower into a modern electric model? Sure. But the savings on gas, the reduction of your personal carbon footprint, and the joy of nearly silent mowing make it all worthwhile.

For more detailed instructions, tips on finding supplies, and wiring diagrams, go to:

arttec.net/Solar_Mower

builditsolar.com/Projects/Vehicles/LeeMower.htm

appropedia.org/Solar_Charged_Lawnmower

Or, read more at our sister site, TreeHugger:

How to Build a Solar-Powered Lawn Mower

READ MORE: Discover More Energy Innovations