Batteries are at the heart of the electrical systems found on any boat or vehicle. Proper battery management, including switching and charging, is essential for safe and reliable operation. The following basic wiring diagrams show how batteries, battery switches, and Automatic Charging Relays are wired together from a simple single battery / single engine configuration to a two engine, one generator, and four battery bank system. For more detailed wiring guidelines please consult a qualified marine electrician or one of the many books available on the subject.