ARCO Zeus A275L Vortec Alternator with Regulator

The ARCO Zeus A275L Vortec Alternator is a high-output 12V unit with Vortec mounting, an external rectifier and dual cooling fans.

Vortec mounting is what distinguishes this from the single foot version, and the engine dictates which is correct. Both are the same alternator electrically. Checking the existing unit's mounting before ordering is the only reliable way to get it right.

Heat is what limits sustained alternator output, and the thermal package here addresses it from several directions. Heat-shedding E-Coat or Cerakote finishes absorb less, the rectifier sits on the exterior of the case, and dual fans move air through it under load.

An alternator that runs cooler holds its rated output instead of derating once the engine space warms up. That matters on a boat charging a large bank underway, where the alternator works hard for hours rather than minutes. Explore more marine alternators.

• Vortec mounting, against the single foot version
• Electrically identical: the engine decides
• Check the existing unit before ordering
• A cooler alternator holds its rating under load