Balmar 120A Saddle Mount Alternator Kit, K6 Pulley

The Balmar 120A Saddle Mount Alternator Kit includes a 60-120-K6 alternator, MC-618 regulator, temperature sensors and mounting hardware.

Buying this as a kit rather than an alternator alone is the point, because a high-output alternator on its own will not charge properly. It needs an external regulator to control it and temperature sensors on both the alternator and the battery, and sourcing those separately is where a charging upgrade usually stalls.

The temperature sensors are what protect the investment rather than being an accessory. An alternator sensor lets the regulator back off before the unit cooks itself, and a battery sensor adjusts charging voltage as the bank warms. Without them a 120A alternator can damage both itself and the batteries.

The 3.15-inch saddle mount is common on Yanmar, Westerbeke and Lehman engines, with a K6 serpentine pulley. Both the mount and the pulley have to match the engine, and isolated grounding keeps the return current in its own cable. Explore more marine alternators.

• A high-output alternator alone will not charge properly
• It needs external regulation and temperature sensing
• Sensors let the regulator back off before damage
• 3.15-inch saddle with K6 serpentine pulley