Zappi measures energy flow so it can adjust charging to the generation left after household use. How it behaves then depends on the selected mode and settings.
In ECO+, a 100% Minimum Green Level aims to avoid sustained grid top-up, pausing when surplus is insufficient after the configured delay. A lower setting permits some grid contribution. Boosts can draw grid power even while ECO+ is selected.
ECO keeps charging with grid top-up where needed. FAST charges as quickly as the vehicle and installation allow, using available solar as well as grid electricity where required. It does not discard the solar simply because FAST is selected.
At Blair Drummond’s Old Barn project, the Zappi was configured alongside the solar and battery installation. For your home, we need to understand when the car is parked and how the battery is controlled so the systems work together.
Using solar in the car can reduce imports, but it also uses electricity that might otherwise earn export payments. We would compare those options rather than promise free mileage or an annual saving without your usage figures.