- Charging System: Both the house and engine batteries are charged by the engine. In boats with mechanical engines, a transfer switch is used. This switch monitors the voltage of both batteries and directs the charge to the one with lower voltage. For Suzuki and Yamaha Digital engines, a dual output alternator is used instead. This alternator can charge both the engine and house batteries separately, eliminating the need for a transfer switch.
- Battery Usage: The house battery powers most of the boat’s functions such as bilge and fish box pumps, electronics, and lights. Meanwhile, the engine battery is responsible for starting the engine and powering the power assist steering.
- Crossover and Safety: A crossover switch is available for emergency situations. If either the engine or house battery runs low, this switch acts like a set of jumper cables, allowing one battery to assist the other. However, it’s important to return this switch to the off position after use to avoid draining both batteries.
- Factory-Installed Battery Charger: Typically, the factory-installed battery charger is set up to charge only the trolling batteries. If a boat doesn’t have trolling batteries, or if an additional charger is added, the setup can be reconfigured to also charge the house and engine batteries. This is particularly useful when the boat is docked in water for extended periods, ensuring that essential functions like the bilge pump remain operational without draining the batteries.