12V/24V Automatically DetectAutomatically detects 12V or 24V DC system voltages (for non-lithium batteries only), and the LCD screen and multiple LED indicators display the solar charging and battery operation information, customizable parameters, and error codes Smart 4-Stage PWM ChargingSmart 4-Stage PWM charging (Bulk, Boost, Float, and Equalization) increases battery life and improves system performance. Intelligent protection against reverse polarity, overcharging, short-circuit, and reverse current. Compact in sizeWhich makes it easy to install virtually anywhere. Multiple battery adaptation Deep Cycle Sealed (AGM), Gel, Flooded and Lithium battery option ready. Wanderer40A|50A Installation Notes The default starting position of the Wanderer controller terminal hatches are closed (in the UP position) that could mistakenly look like an open wire hatch. Make sure to FIRST lower each terminal hatch by screwing the terminals counterclockwise (CCW) to expose the wire terminal hatch to the open position. THEN secure each cable by rotating the screws clockwise (CW) to the closed position.