The 20A/30A/40A Rover MPPT Charge Controllers feature a die-cast aluminum shell that is perfect for heat dissipation while also protecting against general wear and tear. This intelligent controller is not only capable of up to 99% tracking efficiency, but can also self-diagnose system faults. This charge controller displays error codes that can be easily looked up. Capable of automatically detecting 12V/24V systems, this crucial system component can also handle various battery options such as GEL and Lithium. Pair this charge controller with the Renogy BT-1 and Renogy BT app to view system performance in real time and make parameter changes without having to get up!