The Renogy 40A Rover MPPT Charge Controller is the most efficient type of charge controller. With up to 99% tracking efficiency, the Rover ensures maximum power point solar charging that gets more energy to your battery bank. Capable of automatically detecting 12V/24V lead acid battery systems, this crucial component is preset to also work with Gel, Flooded (wet cell), and Sealed batteries(manual setting is required for 24V Lithium battery). When paired with the Renogy BT-1 Module and DC Home app you can view system performance in real-time and make parameter changes without having to get up!