Zappi EV Charger + Solar Integration — Hampstead Eco Home

The intersection of solar PV, home battery storage, and EV charging is a space where most electrical contractors have limited experience. It is not simply a matter of installing a charger on a wall — the charger needs to communicate with the solar inverter, the battery management system, and the property's energy monitoring platform to ensure that the EV charges from surplus renewable energy rather than drawing from the grid.

The client — a homeowner on Templewood Avenue in Hampstead — had a contemporary eco house with a 6kW solar PV array, a 13.5kWh Tesla Powerwall, and a new Tesla Model Y. He wanted to charge the car from his own solar generation as much as possible, with automatic fallback to grid power only when the battery was depleted and solar was insufficient. He had approached three contractors: one had proposed a standard charger with no solar integration, one had proposed a Zappi but admitted he had never installed one, and the third had not returned his call.

The technical requirement was specific: the charger needed to monitor the property's total electrical flow in real time, detect when surplus solar was being exported to the grid, and automatically divert that surplus to the EV battery. When solar generation dropped — on cloudy days or overnight — the charger needed to either pause charging or switch to off-peak grid power, depending on the client's preference and the time of day.

RARE specified the myenergi Zappi 7kW charger — the market-leading solar-aware EV charger in the UK. The Zappi uses a CT clamp installed at the property's incoming supply to monitor energy flow in real time. In "Eco+" mode, it automatically adjusts the charge rate to match available surplus solar: if the property is exporting 3kW of solar, the Zappi charges the EV at 3kW. If cloud cover reduces solar output, the Zappi reduces the charge rate accordingly. If the surplus drops below the minimum charge rate, the Zappi can either pause charging or supplement with grid power, depending on the configured mode.

The installation was completed over two days. Day one was the electrical infrastructure: a new dedicated 32A RCBO circuit from the consumer unit, a 6mm² SWA cable run through the garage to the external charger location, and the CT clamp installation at the incoming supply. The cable run was through an existing garage service route — no surface mounting, no visible trunking, no disruption to the property's clean contemporary aesthetic.

Day two was the Zappi installation, commissioning, and integration. The charger was mounted on a discreet bracket on the garage wall, connected to the property's Wi-Fi, and configured for the client's specific energy setup. The Zappi was set to Eco+ mode as default, with a timed fallback to grid power during the Octopus Go off-peak window (00:30–04:30) to ensure the EV was always fully charged by morning regardless of solar conditions. The myenergi app was installed on the client's phone, giving him real-time visibility of charge source (solar vs grid), charge rate, and energy cost.

The client's first month of charging: 68% from surplus solar, 32% from off-peak grid. Zero peak-rate grid charging. Estimated annual saving compared to a standard charger: approximately £450–£550, depending on solar generation.