Without a solar battery, a solar system works by generating electricity from the sun. The electricity generated by the sun through the solar panels is Direct Current or DC for short. This travels from the panels to an inverter which changes it to Alternative Current or AC for short. AC is what we use in our homes.
This electricity is used by the home first.
Considering most homes don’t use all their electricity during the day the solar system will export any excess electricity to the grid and the electricity retailer will provide a credit for each kilowatt hour exported.
When a solar and a battery system is combined, in most cases, the solar will provide the home with electricity and the excess that isn’t used by the home will charge up the battery.
Once the battery is fully charged all excess electricity after the battery is charged will be sent to the grid.
Once the home is using more electricity than what is being generated by the solar, which is usually at night, the battery will discharge the stored power into the home.