This is a *SOLARPEX MPPT 130D Solar Charge Controller, 30A, 12V/24V* with LCD display, dual USB ports and easy + / - controls. It uses MPPT technology to get maximum power from your solar panels, with max PV input 75V and max PV power 390W for 12V systems and 780W for 24V systems. It safely charges your battery, protects against overcharge and overload, and is ideal for home solar, off-grid and backup power systems.