SAJ + go-e

What Zerofy can do with SAJ and go-e

In practice

• Zerofy can switch your go-e Charger between one and three phases. Solar charging can therefore start at about 1.4 kW of surplus (6 A on one phase) and move to three phases once the surplus passes about 4.1 kW.
• A typical SAJ home system (3–10 kW) reaches the 1.4 kW single-phase minimum on most bright days; three-phase charging from about 4.1 kW needs a sunny midday or a larger system.
• Zerofy gets new SAJ data every 5 minutes and adjusts accordingly. A minimum runtime and an activation threshold in Autopilot keep passing clouds from interrupting charging.
• Zerofy also shows your SAJ battery, so you can see whether surplus goes into the battery or into the car.
• If your car is connected to Zerofy too, turn on Autopilot for either the car or the charger, not both.
• The go-eCharger charges from 6 A, about 1.4 kW on one phase and 4.1 kW on three. Zerofy charges single-phase up to about 3.7 kW of surplus and switches to three phases above that; go-e lists automatic phase switching for Gemini models and HOME V3, so older HOME units stay on the phases they are wired with.

What SAJ and go-e offer on their own

SAJ: SAJ’s Caro wallbox (7 kW, 6–32 A, or 11 kW, 6–16 A) can charge from solar and supports OCPP 1.6J. The manual says PV charging needs an SAJ H2+B2, HS2, AS2 or HS3 storage system plus the eManager.

go-e: go-e’s own route to surplus charging is the go-e Controller, which measures the house connection with six current sensors and works with any inverter brand, including automatic 1/3-phase switching. Without the Controller, go-e relies on external energy managers through its open API, Modbus TCP or OCPP.

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

Setting up SAJ and go-e in Zerofy

1. Connect SAJ

Zerofy reads your plant from the SAJ cloud: you add Zerofy as a developer in the Elekeeper app and then enter your Plant ID in Zerofy.

1. In the Elekeeper app, tap ••• and open Plant Management.
2. Under Developer/Partner, paste the Developer ID shown in Zerofy and confirm access.
3. Copy your Plant ID from Plant Management and paste it into Zerofy.

Good to know: How fresh the data is depends on how often the SAJ cloud updates. For the battery, Zerofy supports forced charging but not switching the battery mode.

Step-by-step guide for SAJ

2. Connect go-e

Zerofy uses the go-e Cloud HTTP API with your charger’s serial number and API token, sets the charging current and switches between one and three phases.

1. Update the charger to firmware 052 or later and the go-e app to 2.3 or later.
2. In the go-e app, go to Internet → Advanced Settings and turn on the Cloud HTTP API.
3. Copy the API token shown there and enter it in Zerofy together with the charger’s serial number.

Good to know: Supported are Gemini 2.0 (serial 400000+), Gemini (200000–399999) and HOME (050000–199999).

Step-by-step guide for go-e

3. Turn on Autopilot

In Zerofy, open your go-e Charger, 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 go-e Charger 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 SAJ solar production.

Learn more about Smart Mode

About SAJ and go-e

SAJ – SAJ (Guangzhou Sanjing Electric) is an inverter maker from Guangzhou, China. Homes usually have the H2 hybrid inverter with B2 battery or the HS2, HS3 or AS2 all-in-one storage systems; the eManager unit and the Caro wallbox tie them together. Monitoring app: Elekeeper.

go-e – go-e is an Austrian charger maker. The current go-eCharger Gemini 2.0 (11 or 22 kW) has documented local and cloud APIs, MQTT, Modbus TCP, a freely configurable OCPP backend and an eSIM; according to the data sheet it is not approved for the Netherlands, France or Italy. Products: go-eCharger Gemini 2.0, Gemini, HOME.

Manufacturer information last checked: October 2026.

All devices that work with SAJ