Optimise Your EV Charger with Solar Surplus in Switzerland

Switzerland's high electricity tariffs make every kilowatt-hour of solar electricity that goes to your EV instead of the grid worth roughly 20–25 Rp more than exported power. For an EV driving 15,000 km annually, shifting 70% of charging to solar surplus could be worth CHF 450–600 per year — every year, for the lifetime of your system.

But surplus charging only works if your charger, inverter, and home energy management system are properly configured to communicate with each other.

What Is Solar Surplus Charging?

Solar surplus charging means your EV charger automatically reduces its charging rate when solar production drops and increases it when solar surplus is available — keeping charging power equal to (or just below) the real-time solar output that exceeds your home's other needs.

This requires:

1. A solar inverter with real-time power measurement and an accessible API
2. A smart EV charger that can accept dynamic power commands
3. An energy management system (EMS) or native integration that reads from the inverter and commands the charger

The Best Integrations for Switzerland in 2026

Fronius GEN24 + Fronius Wattpilot

This is the gold standard for Swiss residential installations. The Fronius Wattpilot reads real-time grid flow data directly from the Fronius Smart Meter without any API configuration. Charging modes:

→ Curious what solar would actually put back in your pocket? Run a free 60-second estimate.

• Eco mode: Charges only when solar surplus exceeds 1.4 kW (the minimum for single-phase charging)
• Next-trip mode: Charges from solar up to a defined departure time, then tops up from grid
• Full mode: Charges at maximum rate regardless of solar status

The Fronius Solar.web app shows EV charging energy as a distinct consumption category, enabling precise self-consumption accounting.

SolarEdge + Wallbox

SolarEdge's Home Energy Management System (HEMS) integrates with the Wallbox Pulsar Max via Modbus. The SolarEdge app shows EV charging in its energy flow diagram and supports scheduled surplus charging with a minimum surplus threshold you define.

Huawei SUN2000 + Huawei EMMA

Huawei's Energy Management and Metering App (EMMA) supports third-party charger integration via OCPP, but native integration works best with Huawei-branded accessories. This setup is gaining traction in Switzerland, particularly in new builds where full Huawei FusionHome ecosystems are installed.

Third-Party EMS Solutions

For mixed-brand setups, EVCC (Electric Vehicle Charge Controller) is an open-source energy management server popular among Swiss solar enthusiasts. It supports virtually every inverter and charger combination via MQTT, Modbus, and REST APIs. A technically confident homeowner can run EVCC on a Raspberry Pi and achieve surplus charging with any combination of compatible hardware.

ZEV Shared Solar Charging — For Multi-Unit Buildings

A ZEV (Zusammenschluss zum Eigenverbrauch) allows residents of a multi-family building to collectively consume solar electricity generated on their shared roof. EV charging is one of the most powerful use cases.

Under a ZEV structure:

• Solar generated on the roof is distributed to all participating units before any surplus is exported
• EV chargers for individual units draw from the shared solar pool
• The building's central energy management system (or a ZEV operator) manages allocation
• Grid energy is purchased collectively at the building meter — often at a commercial tariff lower than individual residential rates

Companies like Helion and local utility subsidiaries now offer turnkey ZEV management for Swiss MFH buildings, including installation of the chargers, inverter, battery, and energy management platform.

→ Before you read on — see what payback looks like for your roof in under a minute.

Configuration Checklist for Surplus Charging

• Confirm your inverter has a CT clamp or smart meter measuring grid export at the main panel
• Ensure your charger firmware is up to date (surplus charging features are often added in firmware, not hardware)
• Set minimum surplus threshold to match your charger's minimum operating current (typically 6A = 1.38 kW single-phase)
• Enable load balancing if you have other high-consumption appliances (heat pump, induction hob)
• Set a charging schedule as backup for days with poor solar production

---