NABCEP PV Installation Professional Practice Exam

The primary function of a battery charge controller is to limit voltage and current from a charging source to regulate state-of-charge. This ensures that the battery is charged efficiently and safely, preventing overcharging, which could cause damage to the battery and reduce its lifespan.

By regulating the charging process, the charge controller monitors the battery's voltage and adjusts the input accordingly, optimizing the charging cycle for different states of the battery. This regulation helps maintain the battery's health and performance over time, making it a crucial component in any system that relies on rechargeable batteries, particularly in solar power applications where the charging source can fluctuate based on sunlight availability.

Other options, while related to battery management, do not encompass the primary role of the charge controller. For instance, increasing the battery’s capacity is not a function of the controller; rather, it's determined by the design and specifications of the battery itself. Disconnecting batteries from the load during overcharge only represents one specific protective measure, while measuring battery health is typically performed by different monitoring systems rather than the charge controller itself.