Arco Starting & Charging 4010 Zeus A225S 225-Amp Marine Alternator J-180 Mount

The Arco Zeus A225S is a high-output 225-amp marine alternator engineered to deliver exceptional power in a compact small-frame design. Featuring a 3.15" J-180 saddle-style mount, this alternator replaces most Hitachi, Lucas, and Mitsubishi small case alternators, making it ideal for Yanmar and similar marine engines.

Advanced Cooling Technology:

The A225S runs 8-20% cooler than conventional alternators thanks to heat-shedding Cerakote or E-coat finish, exterior-mounted rectifiers, and dual cooling fans. Cooler operation means sustained high-amperage output without thermal throttling, perfect for rapidly charging large battery banks on boats, RVs, or commercial vessels.

Key Features:

• Maximum output of 254 amps (cold, 9,000 RPM) with 187 amps sustained at cruise (hot, 6,000 RPM)
• 157 amps sustained output at idle speeds (hot, 3,000 RPM) for excellent low-RPM performance
• 12-volt system with external regulation; compatible with Arco Zeus Bluetooth regulators for lithium battery charging
• 130mm stator with 16-pole rotor and 12 avalanche-rated 50A diodes (6 positive, 6 negative)
• M8 threaded side-mount battery post with terminal block connection
• Standard 6-groove 49mm pulley (49K6) on 17mm diameter shaft with M17 x 1.5 threading
• SAE J1171 Marine Certified for reliable operation in harsh marine environments
• Proudly manufactured in the USA with OEM components

Technical Specifications:

• Voltage: 12V, Output: 14.1V (default)
• Weight: 12 lbs (6.7 kg)
• Cut-in speed: 1,061 alternator RPM
• Maximum alternator RPM: 19,000
• Frame: Small case, 3.15" J-180 saddle mount
• Finish: Black Cerakote or E-coating
• Field type: P-type, External regulation only

This alternator reduces or eliminates the need for onboard generators by maximizing your engine's power generation capability. The advanced coating technology absorbs less heat, allowing the A225S to maintain peak amperage output for extended periods—essential for modern marine electrical systems with house batteries, inverters, and high-demand electronics.