Battery

Every tractor has an on board battery which is mounted under the seat. This battery is charged when the tractor is not in use and can power the tractor for up to 4 hours alone. It is also used to power the tractor when exchangeable battery packs are being loaded and un-loaded and to offer extended or continuous run time.

Exchangeable packs come in 14 kWh and 28 kWh sizes to power the most energy intensive implements continuously with exchanges every 4 to 8 hours. The exchangeable packs mount to the tractor using a standard 3-point hitch system with a quick release latch that can be loaded and un-loaded while the operator remains in the seat. Because the tractor has three 3-point hitches, the battery can be mounted in any of the three locations – middle, front or rear. The tractor can operate with up to 4 batteries including the one on board for traveling long distances hauling heavy loads.

Charging the exchangeable packs can be performed with the battery on or off of the tractor. With 2 exchangeable packs continuous operation on energy intensive tasks can be achieved by quickly swapping a dis-charged pack with a charged one. A discharged battery can charge from grid power or an onsite renewable energy source while the tractor continues its tasks.

The latest advanced lithium batteries are used and will last for over 10 years without maintenance.

Design

The electric tractor is specially designed to take advantage of the electric drive system which is up to 95% efficient at using the power from the batteries with no emissions. This is in contrast to internal combustion engines that are from 10 – 25% efficient and produce large amounts of pollution and greenhouse gasses.

Electric motors have their maximum torque starting at zero ground speed, which is a big advantage for the tractor. Most of the tasks a tractor performs are at start or at low speeds and require high torque. Take for example plowing, pulling, and digging post holes.

The tractor motors allow regenerative braking to conserve battery power and eliminate wear on a braking system.

When driving the operator controls forward, reverse, right, & left, and stopping as well as ground speed with a joystick. Heavy equipment operators have loved this method for articulated control of heavy tasks for years. This type control is called “Drive by Wire”.

Most tractors manufactured today use hydrostatic type automatic transmissions. These are basically two metal plates spinning very close to each other in oil. This smooths out the torque delivery but nearly doubles the required horsepower to perform the same task as older tractors with gears. Electric tractors perform torque control inherently in their design. Using a standard geared transmission allow ranges of ground speed while maintaining torque control from zero to top speed.

The tractor is designed with three 3 point hitches with parallel operation. All the hitches are lifted and lowered using linear actuators capable of lifting 1500 lbs. There is no hydraulic fluid to leak on crops and the actuators are up to 20 times more efficient. The hitches can operate in float position to keep implements working at the most efficient depth. With the addition of a pin the actuators can be locked to lift the whole front or rear of the tractor off the ground for changing tires or tread width in 4” increments from 44 inches – 72 inches. The front and rear hitches are equipped with a latch that can load and unload implements while the operator stays in the seat.

Another design advantage to the electric tractor is weight distribution and a low center of gravity. The battery(s) are mounted low giving a safer center of gravity. Weight distribution can be arranged specifically for the task at hand, for example if a heavy implement is being used on the rear hitch then a battery pack can be quickly mounted on the front hitch or if a loader is on the front than the battery can be on the rear hitch. The mid hitch makes precision cultivation possible for organic farmers because the tool bar is visible right in front of them.

All 3 hitches can be used at the same time for light duty work like planting and harvesting. For example a compost spreader can be mounted on the front hitch, exchangeable battery pack on the mid hitch and seeder on the rear hitch or for harvesting a reaper can be quickly mounted on the front with a battery and conveyor on the mid hitch which deposits the crop in a dump bed on the rear hitch.

There endless possibilities for both pulled implements and powered implements with properly sized electric motors that just need to be plugged in to the battery. The dangerous PTO can be eliminated and efficiency and convenience can be dramatically increased.

Controls

The present electric tractor controls consist of:

  • a power switch for each battery box
  • a joy stick to control ground speed, direction, and turning
  • brakes
  • shift levers
  • 3-point hitch control
  • seat adjustment lever
Production Prototype Brakes and Shift Levers
Production Prototype Brakes and Shift Levers

Lighting and other options and controls can be added.

Electric Tractor Pros and Cons

An electric tractor is a way of performing the same task as a gas or diesel tractor with up to 500% more efficiency at about 1/10th the cost of fuel.

How do you make an electric tractor?

Remove the internal combustion engine, fuel system, cooling system, , charging system, hydraulic system, and exhaust system from a conventional tractor.

Replace it with an electric motor or two, some linear motors, batteries, power controller, and a joy stick for steering and you have a more powerful and more efficient electric tractor.

Advantages of an Electric Tractor:

  1. Better lower end torque i.e. power
  2. Better delivery of power to the ground and steering control.
  3. Lower center of gravity
  4. No fossil fuels required, safer less harmful to environment.
  5. Less heat, Less noise, less vibration, less moving parts, less maintenance, less offensive smells.
  6. Lower cost of maintenance, easier to service, modular subsystems.
  7. Electric motors commonly used for powering heavy equipment so maintenance and repair widely available.
  8. Free low cost power from the sun, after the cost of the Photo Voltaic “solar cells” and batteries and charge controller are recouped.
  9. Tractor batteries can be changed out in a few minutes.
  10. Electric tractor has increased area on board for implements. Three conventional 3-point implements can be operational at the same time.
  11. 3-point attachment systems operated with electric servo motors increasing functionality and ease of use. i.e. can lift and adjust bottom two mounting points independently, great for adjusting attachment angle as well as height. Manual adjustments no longer required.
  12. Multiple functionality of charging system equipment. Can be used to charge tractor and or to power the entire homestead.
  13. Solar power charging system is same as solar home systems making parts, installation, and maintenance less expensive and readily available.
  14.  Tractor can have portable 115VAC inverter power available. Power produced for tractor is available to power devices on the farm anytime or to power the home if grid power is down.
  15. There are many efforts being made to move people to solar based systems; home based solar systems, other countries moving to replace grid power from sun power, Tesla and other electric automobiles companies increasing availability of electric vehicles.
  16. Personal solar charging system costs can be delayed. Tractor can be charged from grid power at a cost savings over petroleum based fueled tractors. Grid power is a little more efficient producer of power than petroleum based engines when including transportation costs, etc.
  17. Weight of batteries is an advantage in tractors as it increases useful traction. Operational is efficiency increased.

dis-Advantages of an Electric Tractor:

  1. Less familiar to public, personal resistance to change, some education required, mis & dis information too common.
  2. Initial cost of Personal solar charging system is high compared to shared cost of delivery of petroleum based fuels. Pays for itself in 5-8 years based on design and multiple uses for system, i.e. charging tractor and powering homes, etc. Option to delay cost by charging tractor from grid power.
  3. Embedded oil companies and internal combustion engine manufactures motivated to resist solar based power systems.
  4. Legislation slow to move in a direction to support personal solar charging systems.
  5. Few electric tractors available until demand increases.
  6. Fewer repair technicians available, but number of qualified are increasing rapidly.