SAJ + OCPP chargers

What Zerofy can do with SAJ and OCPP chargers

In practice

• Zerofy adjusts the charging current of your OCPP charger 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.
• A typical SAJ home system (3–10 kW) needs a sunny midday to reach the 4.1 kW three-phase minimum. Wired single-phase, the charger starts from about 1.4 kW but charges at no more than about 3.7 kW.
• 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.
• Many chargers switch off their own app or solar mode while an external OCPP backend is active (for example enercab, Growatt THOR, SolaX in its OCPP scene), so Zerofy takes over. Zerofy sets the power over OCPP but not the phases, so a three-phase charger needs about 4.1 kW of surplus (3×6 A) unless it switches phases by itself.

What SAJ and OCPP chargers 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.

OCPP chargers: OCPP itself has no solar mode: since 1.6 it carries smart-charging profiles, so the backend sets the current limit and decides when to charge. Solar behaviour therefore comes from whichever system is the backend, or from the charger’s own meter-based mode.

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

Setting up SAJ and OCPP chargers 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 OCPP chargers

You enter Zerofy’s OCPP URL in your charger’s OCPP settings; Zerofy then acts as the backend and can start, stop and set the charging power.

1. Check that your charger supports OCPP 1.6 and lets you change the backend address.
2. In Zerofy, add an OCPP charger and copy the OCPP URL.
3. Paste it into the OCPP settings of your charger’s app or web page and wait for it to connect.

Good to know: Not every OCPP charger lets the owner choose the backend: some need the installer’s service tool (Alfen, ABB), some pick from a preset list (Peblar) or whitelist the address first (Smappee), and some offer no owner OCPP at all (Tesla Wall Connector, Ohme).

Step-by-step guide for OCPP chargers

3. Turn on Autopilot

In Zerofy, open your OCPP 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 OCPP 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 OCPP chargers

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.

OCPP chargers – OCPP (Open Charge Point Protocol) is the open standard from the Open Charge Alliance for communication between a charger and a management system; version 1.6 from 2015 is the most widely used, in its JSON variant 1.6J. A charger can only be connected to one OCPP backend at a time. Products: Any charger with OCPP 1.6J and a freely configurable backend, e.g. Alfen Eve, KEBA KeContact P40, Charge Amps Halo, Autel MaxiCharger, enercab smart.

Manufacturer information last checked: October 2026.

All devices that work with SAJ