Mastervolt Alpha Pro III 3-Step Charge Regulator

Description

The Mastervolt Alpha Pro III is an advanced three-stage alternator regulator designed to turn a standard or high-performance alternator into a more effective battery-charging source. It monitors battery voltage and temperature while also managing alternator field current, helping reduce charging time without sacrificing battery protection or alternator reliability.

The regulator supports both 12V and 24V systems and is compatible with a wide range of battery chemistries, including lithium-ion. With up to 20A of field-current capability, it can control high-output alternators rated up to approximately 400A, making it suitable for substantial service banks that need fast charging while the engine is running.

Battery temperature and voltage sensing allow the regulator to adjust charging behavior and reduce the risk of overcharging. Engine-load management helps smooth alternator demand so abrupt electrical loading has less effect on engine RPM, noise, and drivability. A keep-alive feature supports more reliable tachometer operation on installations where the alternator field signal is also used for engine-speed indication.

MasterBus communication can share alternator RPM, operating status, and charge information with the rest of a compatible Mastervolt system. This allows alternator charging to become part of a broader integrated power-management strategy rather than operating as an isolated subsystem.

For boats and vehicles that need faster alternator charging, temperature-controlled three-stage regulation, lithium compatibility, and MasterBus integration, the Alpha Pro III provides a sophisticated alternator-control solution. Explore our full range of alternator parts & accessories.