Our DC combiner boxes offer users the possibility to integrate short-circuit and overvoltage protection, as well string monitoring solutions (I,V, T and SPD and switch isolator status), for PV systems using central inverters with PV panels in trackers and fix tilt systems. In off-grid applications, combiner boxes are crucial for consolidating multiple solar panel outputs into a single DC output that feeds into battery storage systems or DC loads. In a typical solar PV system, each string produces DC power. What it is: A solar combiner box (also called a PV combiner box.