A direct current (DC) disconnect switch is installed between the inverter load and the solar array. The disconnect switch is used to safely de-energize the array and isolate the inverter from the. Safety disconnect switch are required by the National Electric Code (NEC) on the AC-side of the inverter to safely disconnect and isolate the inverter from the AC circuit. This is for troubleshooting and performing maintenance on the system. For grid-connected systems,. A charge controller regulates the amount of charge going into the battery from the module to keep from overcharging the battery. Charge controllers can vary in the amount of amperage they can regulate. Some models will include additional features such as. Several tools are available to help the solar user to monitor their system. On stand-alone or of-grid PV systems, the battery meter is used.