Balmar 100A Spindle Mount Alternator, J10 Pulley

Description

The Balmar 621 Series 100A Spindle Mount Alternator is designed for 12V marine charging systems using a 1-inch Motorola-style or 2-inch Delco-style single-foot mount. Its J10 AltMount serpentine pulley and isolated-ground configuration make it a strong choice for boats that already have compatible external regulation and want to increase charging capacity without buying a complete regulator kit.

The 1-inch mounting arrangement is typical of Westerbeke, Lehman, Hino, and Pathfinder engines. The 2-inch Delco-style configuration is commonly found on Volvo Penta gas and diesel engines, John Deere, Perkins, MerCruiser, Pleasurecraft, Crusader, Indmar, Marine Power, and other GM-based marine engines.

The 100-amp output can improve battery-bank recovery on cruising boats with significant electrical demand. The J10 ten-rib serpentine pulley provides a broad belt-contact surface intended for systems designed to transmit the increased mechanical load of high-output charging. Isolated grounding keeps the alternator’s electrical ground separate from the case.

Balmar 621-100-SR-IG is the listed replacement reference. Mount dimensions, pulley alignment, regulator configuration, belt sizing, and charging-cable capacity should be confirmed before installation. See the rest of our marine alternators.