Alpha ESS Storion SMILE (battery)
The Alpha ESS Storion SMILE is a residential and light-commercial battery energy storage system that pairs with a PV inverter to store and dispatch solar energy. This ModbusCloud template communicates over Modbus RTU via the RS485 port and reads battery state of charge, cumulative energy, and instantaneous power. Write registers allow remote control of the battery dispatch mode through two control channels. For installers and energy managers, the template gives local, cloud-independent visibility and control of the Alpha ESS Storion SMILE battery in the ModbusCloud portal.
- Protocol
- Modbus RTU
- Connection
- RS485
- Registers
- 5, read and write
- Brand
- Alpha ESS
- Last updated
Registers (5)
3 read, 2 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power | W | Read | |||
| energy | Wh | Read | |||
| soc | % | Read | |||
| batterymode_a | Write | ||||
| batterymode_c | Write |
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Use cases
- Monitor battery state of charge continuously to verify the system charges fully before evening peak demand.
- Track cumulative battery energy over time to detect capacity degradation across seasons.
- Alert on sustained negative power values indicating the battery is drawing from the grid unexpectedly.
- Compare instantaneous battery power against solar production to verify self-consumption targets are met.
- Report daily charge and discharge cycles to building owners for energy cost reconciliation.
Installation
Enable Modbus on the Alpha ESS Storion SMILE: navigate to the inverter function menu, select the Modbus section, and set Modbus to enabled in slave mode with the default slave ID 0x55 (decimal 85).
Connect the ModbusCloud Gateway to the inverter RS485 port using the RJ45 CAN/RS485 socket: use pins 3 and 6 for the A+/B- twisted pair, set the baud rate to 9600, 8N1, no parity.
In the ModbusCloud portal, add a new device, import the Alpha ESS Storion SMILE (battery) template, and set the unit ID to 85; confirm the RTU serial parameters match your wiring.
Verify the connection by checking live readings for the soc register (address 258): a value between 0 and 100 confirms communication is established correctly.
Things to watch for
Why does the soc or power register return zero or garbage?
Alpha ESS Storion SMILE registers return scaled integers. The power register at address 294 is a signed int16: confirm your Modbus master is reading it as signed, not unsigned. A reading of 65000+ is almost always an uncast negative value. Also verify the slave ID is set to 85 (0x55), which is the factory default.
The Gateway connects but no register values appear. What should I check?
Confirm Modbus is enabled on the inverter via the function menu under the Modbus or communication section. Check that the RS485 wiring uses pins 3 and 6 of the RJ45 CAN port and that the baud rate is 9600, 8N1. A missing or reversed A+/B- polarity on the RS485 pair is a common cause of silence.
Reads work but writes to batterymode_a or batterymode_c have no effect.
Alpha ESS dispatch mode requires commands to be sent in the correct sequence: the dispatch mode register must be written last. Writing only one of the two control channel registers without completing the full sequence may be silently ignored. Consult the Alpha ESS Modbus protocol documentation for the required write order before sending commands.
Is it safe to write to the batterymode registers during normal operation?
Writing to batterymode_a (address 2127) or batterymode_c (address 2133) changes the active dispatch mode of the battery system. Incorrect values can force the battery into unwanted charge or discharge states, potentially tripping protection limits or affecting inverter warranty conditions. Always test writes in a controlled environment and restore normal mode after any automated dispatch sequence.
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