ARCO Zeus A275L 3.15-Inch Alternator, Isolated Ground

Description

The ARCO Zeus A275L 3.15-Inch Alternator with Isolated Ground and Terminal Block is designed for high-energy marine, RV, military, and commercial charging systems where large battery banks and sustained electrical loads demand substantially more output than a conventional alternator can provide. Its 3.15-inch saddle-style mounting configuration replaces many small-case Hitachi, Lucas, and Mitsubishi alternators and is commonly applicable to Yanmar installations.

The A275L is engineered around sustained high-output operation. Heat-shedding E-Coat or Cerakote finishes, an externally located rectifier, dual cooling fans, and OEM components help reduce operating temperature so the alternator can maintain more amperage over longer periods. It is also optimized for output at idle, helping create useful charging power when the engine is running slowly and potentially reducing dependence on a separate generator.

This 12V large-frame unit uses a 138mm stator, 16 rotor poles, and a P-type field. It is internally regulated with an adapter for optional external regulation. Pairing it with an ARCO Zeus Bluetooth Alternator Regulator allows more advanced charging control and is recommended for lithium battery charging or maximum system performance. Default output voltage is 14.1V.

ARCO lists up to 311A cold output at 9,000 alternator RPM, 227A sustained hot cruising output at 6,000 RPM, and 198A sustained hot idle output at 3,000 RPM. Cut-in occurs at 1,061 alternator RPM, maximum alternator speed is 19,000 RPM, and maximum continuous operating temperature is 110°C.

Hardware includes an M8 side-mount battery post, 49K6 six-groove 49mm pulley, 17mm shaft threaded M17 x 1.5, and included pulley nut and washer. The rectifier uses six positive and six negative 50A avalanche-rated diodes. This isolated-ground version includes a terminal block for appropriate system integration.

ARCO notes that installations replacing a standard single V-belt drive require upgrading to a serpentine system. The alternator is SAE J1171 certified and proudly made in the USA. There is more in our marine alternators.