Adapter Box
The Solax Adapter Box integrates a heat pump with dry contact into the Solax ecosystem, controlled by the X1-Hybrid G4 / X3-Hybrid G4 hybrid inverter. RS485 communication, three operating modes (Manual, SmartSave, Disabled), no external power supply required. It transforms excess solar energy into useful heat, reducing energy costs.
The Solax Adapter Box is the interface module that allows the Solax hybrid inverter to intelligently control a heat pump with dry contact function, integrating the heating system into the photovoltaic energy ecosystem. Thanks to RS485 communication with the inverter, the heat pump is automatically activated based on the available solar energy, the battery SOC, and the set preferences.
How does the Solax Adapter Box work?
The Adapter Box is installed between the Solax inverter (X1-Hybrid G4 or X3-Hybrid G4) and the heat pump. It communicates with the inverter via RS485 and controls the heat pump’s dry contacts through an internal relay. The inverter monitors the power produced, the battery SOC, and the user’s consumption, and autonomously decides when to activate or deactivate the heat pump according to the energy management logic set by the user. The result is that excess solar energy—which would otherwise be fed into the grid or wasted—is converted into useful heat for heating or domestic hot water production.
Adapter Box Technical Specifications
| Inverter compatibility | Solax X1-Hybrid G4, X3-Hybrid G4, X1-Boost G4 |
| Communication with inverter | RS485 (RJ45 connector, pins 3/6/7/8 for G4) |
| Heat pump control type | Dry contact — K3/K4 |
| Operating modes | Disabled / Manual / SmartSave |
| Own power supply | Not required (powered by inverter via RS485) |
| Installation | Plug & Play, wall mounting |
| Dimensions | 75 × 125 × 125 mm |
| Weight | 0.4 kg |
| Pump compatibility | Pumps with dry contact, SG Ready (mode 2 and 3) |
The three operating modes of the Adapter Box
The Adapter Box supports three modes configurable from the inverter menu or the SolaX Cloud app. In Disabled mode, the function is inactive. In Manual mode, the user activates and deactivates the pump directly from the inverter or the app. In SmartSave mode, the inverter automatically controls the pump based on configurable thresholds: available grid power, battery SOC, operating time slots, and minimum/maximum daily activation duration.
What is included in the package?
- Solax Adapter Box module
- RS485 communication cable for connection to the inverter
- Wall mounting kit
Frequently Asked Questions
Is my heat pump compatible with the Solax Adapter Box?
The Solax Adapter Box is compatible with any heat pump equipped with a dry contact or SG Ready function. The module controls the pump via the clean contact K3/K4, which opens and closes the internal relay to activate or deactivate the pump. The vast majority of residential and commercial heat pumps have this interface. Check your heat pump’s manual for the presence of external contact terminals or SG Ready function.
Which Solax inverters does the Adapter Box work with?
The Solax Adapter Box is compatible with the hybrid inverters X1-Hybrid G4 (single-phase) and X3-Hybrid G4 (three-phase), as well as the X1-Boost G4 model. It connects to the COM/RS485 port of the inverter via RJ45 cable, using pins 3, 6, 7, and 8 for the G4 series. It is not compatible with earlier generation Solax inverters (G3 and earlier) or with other inverter brands.
How does the Adapter Box’s SmartSave mode work?
In SmartSave mode, the Solax inverter automatically activates the heat pump when: (a) the power fed into the grid exceeds a user-configured threshold (available solar surplus), or (b) the battery SOC has reached the desired charge level. The pump is deactivated when the load’s power consumption exceeds the configured threshold or the battery SOC drops below the set minimum. You can also set minimum/maximum daily operating times and priority activation time slots.
Does the Adapter Box require its own power supply?
No. The Solax Adapter Box is powered directly through the RS485 communication cable connected to the Solax inverter (12V supplied by the inverter via pins 4 and 5 of the RJ45 connector). No external power supply or connection to the electrical grid is required for the module itself—only for the heat pump it controls, which maintains its own independent main power supply.
Can I connect both the Adapter Box and the EVC wallbox to the same Solax inverter?
Yes. You can connect both the Adapter Box and a Solax EVC wallbox to the same Solax G4 inverter, using an RJ45 splitter on the inverter’s RS485 port. This way, the inverter can coordinate both electric vehicle charging and heat pump control, maximizing the use of excess solar energy for both loads.
