Adding a battery is a great way to augment your solar system as it will allow you to have stored power in a power outage.
The non-profit Solar United neighbors has a good description of how this works and a Battery Storage Guide.
Reports on how communities have added solar+storage on homes and businesses.
Understanding Solar+Storage: Answers to Commonly Asked Questions About Solar PV and Battery Storage
Energy Storage Policy Best Practices from New England: Ten Lessons from Six States
ConnectedSolutions: A New State Funding Mechanism to Make Battery Storage Accessible to All
ConnectedSolutions: The New Economics of Solar+Storage for Affordable Housing in Massachusetts