Marine batteries are specially designed to provide reliable power for boats and watercraft, supporting both engine starting and onboard electronics. Built to withstand vibration, moisture, and harsh marine conditions, these batteries come in three main types: starting batteries (for quick bursts of power to start engines), deep cycle batteries (for steady power over time), and dual-purpose batteries (combining both functions). Common chemistries include lead-acid, AGM, and lithium-ion, chosen based on performance, maintenance needs, and usage type.