Home battery storage systems can be added along with a new solar installation, after a solar installation, or even without a solar panel system. There are two primary setups for solar plus battery storage installations; DC-coupled systems and AC-coupled systems.
DC-coupled storage systems are the setup for new solar panel systems. In this type of install, a charge controller regulates the DC power from the solar panels to prevent the batteries from overcharging. DC coupled systems are typically less pricey because only one inverter is needed. Here’s a diagram –
AC-coupled systems are common for existing solar installations. One of the reasons for this is that the existing connection from the solar panels to the inverter does not need to be rewired. Instead of needing a charge controller, the grid-tied inverter controls the DC flow. In an AC-coupled system, the critical load subpanel manages current from both the grid-tied inverter and the battery-based inverter.
