The REDARC BCDC1240D is a 12V, 40A In-vehicle DC to DC Battery Charger designed to keep your auxiliary battery charged when driving or with portable solar panels when parked. It uses multi-stage DC-DC charging, a system that allows optimum charging levels for your auxiliary battery. Dual Battery Charger with solar input The DC to DC battery charger works from a wide operating range (9-32V) and provides the option of charging from both 12V and 24V vehicle systems. Additional features include a Maximum Power Point Tracking (MPPT) solar regulator, which allows the maximum amount of power to be delivered from your solar panels to your auxiliary battery. This Solar Ready smart charger also acts a dual battery isolator. If the voltage gets too low, the start battery is protected. It's fan free creating a quiet operation, is fully sealed, and has multiple levels of fault protection. The SEMA Global Media Awarding winning BCDC1240D is perfect for charging AGM, Gel, Standard Lead Acid, Calcium, and LiFePO4 batteries. The in-vehicle dual battery range keeps your auxiliary battery banks charged to their optimal levels and lets you continue your adventure uninterrupted. This DC-DC battery charger with solar input has been proven to work in all types of terrains, including deep water crossings, and stands up against extreme heat (up to 176 deg F). It's fully sealed against the risk of infiltration from water and dust and will hold up to the adventure at hand. It's designed to maximize the performance and life of your auxiliary battery and is suited for battery bank sizes of 200AH and above in most applications. Made in Australia by REDARC this amazing range has undergone years of testing in some of the harshest conditions on the planet. REDARC has been in business for nearly 40 years and all of our products are made tough enough to take anything nature can throw at them.