Hoymiles + Fronius Wattpilot

What Zerofy can do with Hoymiles and Fronius Wattpilot

In practice

• Zerofy adjusts the charging current of your Wattpilot but doesn’t switch phases. On a three-phase connection, solar charging needs at least about 4.1 kW of surplus (6 A × 3 × 230 V); on a single-phase connection about 1.4 kW.
• Hoymiles systems range from balcony kits to rooftop systems (0.8–10 kW). A balcony system never reaches the 1.4 kW needed to start charging; a rooftop system of a few kW does on bright days, and three-phase charging needs about 4.1 kW.
• Zerofy gets new Hoymiles data only every 15 minutes, so charging reacts to clouds with some delay. A slightly higher activation threshold and a minimum runtime in Autopilot keep it steady.
• If your car is connected to Zerofy too, turn on Autopilot for either the car or the charger, not both.
• In its own surplus mode the Wattpilot starts at 1.38 kW on one phase, adjusts in 0.23 kW steps and switches to three phases above 4.14 kW, where it steps in 0.69 kW; the switching level can be changed in the app. Via OCPP, Zerofy sets the charging power but not the phases, so the minimum is 6 A: about 1.4 kW single-phase or 4.1 kW three-phase.

What Hoymiles and Fronius Wattpilot offer on their own

Hoymiles: Hoymiles sells its own AC chargers (VAS-7-G2 single-phase 7 kW, VAT-11-G2 and VAT-22-G2 three-phase) with a green power mode that follows PV surplus, but only together with a Hoymiles storage inverter (HYS, HAS, HYT, HAT), not with microinverters. An 800 W balcony system on its own never reaches the about 1.4 kW a charger needs at its 6 A minimum.

Fronius Wattpilot: The Wattpilot’s own PV surplus charging needs a Fronius inverter (GEN24, Verto, or SnapINverter/IG with Datamanager 2.0) with a Fronius Smart Meter at the feed-in point, talking over the Solar API in the same network. Other inverter brands only work with an extra Fronius Smart Meter IP or Datamanager Box 2.0 plus Smart Meter; the Wattpilot then also appears in Fronius Solar.web.

Zerofy connects the two: it reads Hoymiles production and controls your Wattpilot to match, together with your other devices in one app, with dynamic tariffs and forecast-based Smart mode.

Setting up Hoymiles and Fronius Wattpilot in Zerofy

1. Connect Hoymiles

Zerofy connects to the Hoymiles S-Miles Cloud with your S-Miles account and reads your PV production.

1. If your installer hasn’t set up your plant yet, register it in the S-Miles Installer app (use DIY mode if you install it yourself).
2. In Zerofy, add an inverter, choose Hoymiles and log in with your S-Miles credentials.
3. Use Autopilot (Solar Mode) to switch devices on solar surplus.

Good to know: Zerofy reads PV production only from Hoymiles, not grid meter or battery data, and stores the power history in 15-minute steps (5 minutes for most other brands).

Step-by-step guide for Hoymiles

2. Connect Fronius Wattpilot

The Wattpilot connects to Zerofy via OCPP 1.6J; you enter the connection details from Zerofy in the Solar.wattpilot app.

1. In Zerofy, add a Fronius Wattpilot and copy the OCPP connection details.
2. In the Solar.wattpilot app, go to Internet → OCPP and enter the details.
3. Save and wait until the status shows the connection is established.

Step-by-step guide for Fronius Wattpilot

3. Turn on Autopilot

In Zerofy, open your Wattpilot, turn on Autopilot and choose Solar – or Smart to also use dynamic tariffs and forecasts. Set the priority, activation threshold and minimum runtime.

Dynamic tariffs

Zerofy can also run your Wattpilot on dynamic electricity prices (EPEX Spot or Nord Pool, e.g. Tibber or aWATTar) or on a fixed time-of-use tariff. Smart mode combines those prices with forecasts of your household consumption and your Hoymiles solar production.

Learn more about Smart Mode

About Hoymiles and Fronius Wattpilot

Hoymiles – Hoymiles (Hangzhou, China) is one of the largest microinverter makers. In Europe it is best known for balcony systems such as the HMS-800W-2T (switchable 600/800 W) with the MS-A2 balcony battery, and it also sells HYS/HYT hybrid inverters with home batteries. Monitoring app: S-Miles Cloud (S-Miles app).

Fronius Wattpilot – The Wattpilot is the EV charger of the Austrian inverter maker Fronius, built for solar charging with automatic 1/3-phase switching and surplus charging from 1.4 kW. The Flex has LAN and Wi-Fi, a §14a input and a Pro version with MID and Eichrecht; it is mainly sold through installers. Products: Fronius Wattpilot Flex Home, Wattpilot Flex Pro, Wattpilot Go, Wattpilot Home.

Manufacturer information last checked: October 2026.

All devices that work with Hoymiles