Electric Planter Drives (EPDs) allow farmers to upgrade their existing planters. They are essentially small electric motors installed on each row unit of the planter to drive the seed meter, thus replacing the ground or hydraulic drives, eliminating maintenance-intensive bearings, chains, sprockets, and clutches, while offering precise on-the-go individual row shutoff, variable-rate seeding by section, and turn compensation-all controlled by electronic devices. The motors run off the tractor's battery or alternator. (Many new planters now come with factory-equipped EPDs.)