Balance of System (BoS)

BOS stands for “Balance of System”. You’ll most commonly hear it used in the context of a PV systems, where the hardware making up such systems has traditionally been split into the solar modules (panels) and “the rest” (BOS): inverter, cabling, frames and so on. In the past, the modules made up most of the system cost, with “the rest” being the minor part. These days, the much reduced cost of solar modules means that the reverse is true.