There is arguably no more important electrical repair you can do on your yacht to increase comfort and convenience than installing a high power marine alternator. Having a high power alternator will significantly increase the availability of electrical power on board.
This will result in increased safety, improved ability to operate electronics, improved illumination, colder beer, and the ability to run a watermaker, windlass, inverter, and other high-power equipment. It is not the only component that is important in a fully working marine electrical system; additional components will be covered in subsequent sections; nonetheless, in many situations, the alternator serves as the cornerstone of a contemporary high performance system.
You are now ready to choose an alternator after properly inspecting what you presently have. Begin with a proper voltage, case size, and mounting foot. Then you must choose an output size based on your electrical requirements, battery size, and pulley type.
If you just have a single 3/8″ broad belt, your 12 volt alternator will be restricted to roughly 70 amps. With a single 12″ belt, you’ll be restricted to around 110 amps with a 12 volt alternator. Anything beyond 110 amps for a 12 volt system will need the use of multiple belts or a serpentine belt. The image below depicts the extensive range of alternators available for purchase at EvoTec.
