Automotive alternators rely on simple voltage regulators, either internal or external, whose primary function is to keep the starting battery charged. However, because efficiency and battery life are more important in maritime applications, the regulators are more complicated, precise, and adaptable. Although internally controlled alternators are available, most marine alternators rely on external regulators to provide such functionality. Many of them may be tailored to the kind and size of the home battery bank, monitoring equipment, and operational circumstances.
The design goals of marine alternators and automotive alternators have diverged in the last decade. Even if the load requirements are similar, they are not substitutes for each other. Especially marine alternators must have higher performance than modern automotive alternators due to the harsh offshore environment.