Power source and control system for a lawn mower

Abstract

A battery-powered eclectic lawn mower includes battery packs mounted on a docking stations of a bus bar by way of a gravity-biased engagement. The lawn mower also includes a priority charging control logic for giving priority of charge to battery packs that have a state of charge over a threshold. The lawn mower also includes a live to drive system which alerts the user when the lawn mower is capable of moving in response to manipulation of controls. The lawn mower also includes a variable speed control which adjusts a sensitivity of speed controls such that more precise, slower speed control of the lawn mower is achieved when mowing around trees and the like.

What is claimed is: 
     
         1 - 64 . (canceled) 
     
     
         65 . An electric lawn mower, the electric lawn mower comprising:
 a frame;   a drive wheel supporting the frame above a ground surface;   a cutting deck coupled to the frame;   a drive motor mounted to the frame and driving rotation of the drive wheel to move the electric lawn mower over the ground surface, and   a deck motor mounted to the cutting deck and configured to drive rotation of a blade under the cutting deck to cut grass under the cutting deck;   a plurality of battery packs supported by the frame and configured to provide electrical power to the drive motor and to the deck motor;   an electronic controller coupled to the drive motor and to the deck motor, the electronic controller configured to:   determine a maximum steady state current value for the plurality of battery packs;   determine a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor;   control the drive motor to maintain a motor current of the drive motor below the maximum drive current value; and   control the deck motor to maintain a motor current of the deck motor below the maximum deck current value.   
     
     
         66 . The electric lawn mower of  claim 65 , wherein
 the drive motor is a first drive motor of a plurality of drive motors mounted to the frame and the drive wheel is a first drive wheel of a plurality of drive wheels supporting the frame above a ground surface,   each drive motor of the plurality of drive motors is associated with a respective drive wheel of the plurality of drive wheels to move the electric lawn mower over the ground surface,   the deck motor is a first deck motor of a plurality of deck motors, and the blade is a first blade of a plurality of blades under the cutting deck, and   each deck motor of the plurality of deck motors is configured to drive rotation of a respective blade of the plurality of blades to cut grass under the cutting deck.   
     
     
         67 . The electric lawn mower of  claim 66 , wherein, to determine a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor, the motor is further configured to:
 calculate a maximum aggregate drive motor current for the plurality of drive motors and a maximum aggregate deck motor current for the plurality of deck motors based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor,   divide the maximum aggregate drive motor current by a total number of the plurality of drive motors to determine the maximum drive current value, and   divide the maximum aggregate deck motor current by a total number of the plurality of deck motors to determine the maximum deck current value.   
     
     
         68 . The electric lawn mower of  claim 67 , wherein
 the electronic controller includes a vehicle control module including a processor and memory, a drive controller for each of the plurality of drive motors, and a deck controller for each of the plurality of deck controllers,   the vehicle control module is configured to determine and provide the maximum drive current value to each of the plurality of drive controllers and is configured to determine and provide the maximum deck current value to each of the plurality of deck controllers.   
     
     
         69 . The electric lawn mower of  claim 68 , wherein
 each of the plurality of drive controllers is configured to control an associated drive motor to maintain motor current of the associated drive motor below the maximum drive current value, and   each of the plurality of deck controllers is configured to control an associated deck motor to maintain motor current of the associated deck motor below the maximum drive current value.   
     
     
         70 - 74 . (canceled) 
     
     
         75 . A method of controlling power distribution in an electric lawn mower, the method comprising:
 determining, by an electronic controller, a maximum steady state current value for a plurality of battery packs supported by a frame of the electric lawn mower and configured to provide electrical power to a drive motor and to a deck motor, where the drive motor is mounted to the frame and configured to drive rotation of a drive wheel to move the electric lawn mower over a ground surface and where the deck motor is configured to drive rotation of a blade to cut grass under a cutting deck;   determining, by the electronic controller, a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor;   controlling, by the electronic controller, the drive motor to maintain a motor current of the drive motor below the maximum drive current value; and   controlling, by the electronic controller, the deck motor to maintain a motor current of the deck motor below the maximum deck current value.   
     
     
         76 . The method of  claim 75 , wherein the drive motor is a first drive motor of a plurality of drive motors mounted to the frame and the drive wheel is a first drive wheel of a plurality of drive wheels supporting the frame above a ground surface, and wherein the deck motor is a first deck motor of a plurality of deck motors, and the blade is a first blade of a plurality of blades under the cutting deck, the method further comprising
 driving, by each drive motor of the plurality of drive motors, a respective drive wheel of the plurality of drive wheels to move the electric lawn mower over the ground surface, and   driving, by each deck motor of the plurality of deck motors, a respective blade of the plurality of blades to cut grass under the cutting deck.   
     
     
         77 . The method of  claim 76 , wherein determining a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, the duty cycle of the drive motor, and the duty cycle of the deck motor includes:
 calculating a maximum aggregate drive motor current for the plurality of drive motors and a maximum aggregate deck motor current for the plurality of deck motors based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor,   dividing the maximum aggregate drive motor current by a total number of the plurality of drive motors to determine the maximum drive current value, and   dividing the maximum aggregate deck motor current by a total number of the plurality of deck motors to determine the maximum deck current value.   
     
     
         78 . The method of  claim 77 , wherein the electronic controller includes a vehicle control module including a processor and memory, a drive controller for each of the plurality of drive motors, and a deck controller for each of the plurality of deck controllers, the method further comprising:
 providing, by the vehicle control module, the maximum drive current value to each of the plurality of drive controllers; and   providing, by the vehicle control module, the maximum deck current value to each of the plurality of deck controllers.   
     
     
         79 . The method of  claim 78 , wherein
 controlling, by each of the plurality of drive controllers, an associated drive motor to maintain motor current of the associated drive motor below the maximum drive current value, and   controlling, by each of the plurality of deck controllers, an associated deck motor to maintain motor current of the associated deck motor below the maximum drive current value.   
     
     
         80 - 154 . (canceled)