Minn Kota On-Board Marine Chargers are engineered with a microprocessor-based design to protect batteries, charge faster, and help extend battery life. By monitoring factors like temperature and state of charge, they deliver a faster, more precise charge. Multi-stage charging regulates the proper amount of charge at the proper time and automatic shut-off extends the life of the battery by shutting down when charging is complete. This series of on-board chargers charge batteries up to twice as fast thanks to new, more precise monitoring. Waterproof, shock, and vibration resistant aluminum construction. Saltwater tested and corrosion-resistant. Short circuit, reverse polarity, arc, and ignition protected.