There’s something zen about sitting atop a riding mower. Until you power up that gas-guzzling monster, which is so loud you can’t hear the Game of Thrones podcast playing through your earbuds. But Northeast Ohio-based Cub Cadet’s RZT-S Zero electric riding mower is an efficient, quiet alternative. Engineer Mike Goebel shows us how the $3,999 zero turn-style mower works.
Like a Tesla or Chevy Volt electric car, the RZT-S Zero has regenerative braking, which actually puts power back into the batteries. When the mower is going down a hill, built-in resistance will slow it down if you aren’t pressing the gas pedal. “Instead of acting as a motor, it acts as a generator,” says Goebel. It’s not a ton of power, but it could mean a few extra minutes of cut time.
Cub Cadet’s steering wheel-based zero turn gas mowers employ a complicated array of mechanical linkages between the front and rear wheels to accomplish a zero-radius turn. But the electric version uses front-wheel sensors to monitor your direction and alert the rear wheels which direction they need to spin and how fast. “It’s a much smoother ride,” Goebel says.
Four 12-volt rechargeable batteries power the mower. They give it about a 60- to 90-minute cut time, enough for about 1 acre of grass. The mower’s software monitors consumption, and when the system is down to 10 percent, it goes into power-saving mode, which shuts off the blades to conserve energy. “You still have the drive wheels,” says Goebel. “It will go for 1 1/2 or 2 miles.”
The RZT-S Zero’s display shows battery life and speed. An inverted triangle displays the load on the power system and how efficiently you are operating the mower. The more the triangle fills up beyond a line in the center, the faster the battery drains. “It’s an indication of, Maybe I should slow down,” says Goebel. “If I stay in the middle, I’ll get that acre- to acre-and-a-half of cutting time.”
Four silent-running electric motors individually power the two back wheels and twin 21-inch cutting blades. Having one motor for each wheel and blade eliminates the need for a system of belts found in gas-powered mowers, cutting down on the need for replacement parts since belts wear out over time. “Each motor has its own controller,” says Goebel. “So it knows what [the other] motors are doing at any particular time.” If one blade is over taller grass, the motor senses that and gets extra power to complete the cut. “It’s going to adjust both motors so that they’re at optimum operating power,” Goebel says.