Low-RPM 24V Charging for Marine and Mobile Power Systems

The ARCO 24V 4kW LTO SF12 High Output Alternator combines substantial charging capacity with Low Turn-On technology for increased electrical output at lower engine speeds. Its native 24V rotor and field system improves efficiency and reduces operating heat, while delivering strong output for large battery banks in marine, RV, commercial and off-grid applications. External-only regulation enables charging to be controlled by a compatible external regulator, with an isolated ground, side-mounted M8 battery post and 49mm K6 pulley supporting integration into compatible electrical and engine systems.

Key Features

• Low Turn-On Performance: Begins producing power from 1,072 alternator RPM, supporting charging at lower engine speeds and idle conditions.
• 4kW Output Class: Produces up to 144A / 3,960W at 27.5V under cold maximum-output testing.
• Strong Sustained Output: Delivers 130A / 3,575W at 6,000 RPM and 108A / 2,970W at 3,000 RPM under hot sustained-output testing.
• Native 24V Architecture: Uses a 24V rotor and field current to improve efficiency and reduce heat compared with designs based on 12V rotor architecture.
• External Regulation: External-only configuration works with a compatible P-Type external regulator for controlled battery charging.
• Isolated Ground: Provides electrical separation between the alternator and engine ground for compatible marine installations.
• Side Battery Post: M8 threaded side-mounted battery post supports practical high-current cable routing.
• 49mm K6 Pulley: Six-groove 49mm pulley supports compatible serpentine belt drive arrangements.
• Thermal Management: Heat-shedding coatings, an externally mounted rectifier and dual cooling fans help control operating temperatures during sustained charging.
• SAE J1171 Certified: Certified for use in applicable marine environments.

Low Turn-On operation makes this alternator particularly suited to systems where useful charging output at idle and lower engine RPM is important. Its combination of high sustained output, external regulation and thermal management supports demanding 24V energy systems.