Alpha ESS Storion SMILE (pv)
The Alpha ESS Storion SMILE is a hybrid PV inverter and battery energy storage system for residential and light-commercial installations. This Modbus TCP template reads the total AC active power output of the inverter, individual DC power from up to six PV string inputs, and cumulative PV energy yield. All registers are read-only and are polled from the inverter over the local Ethernet port at port 502. Connecting the Alpha ESS Storion SMILE to the ModbusCloud Gateway gives installers a continuous, cloud-based record of generation performance across all PV strings.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 8, read only
- Brand
- Alpha ESS
- Last updated
Registers (8)
8 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power_a | W | Read | |||
| power_b | W | Read | |||
| power_c | W | Read | |||
| power_d | W | Read | |||
| power_e | W | Read | |||
| power_f | W | Read | |||
| power_g | W | Read | |||
| energy | Wh | Read |
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Use cases
- Monitor total AC active power output to verify the inverter is operating within its rated capacity during peak generation hours.
- Compare individual PV string powers across all six inputs to detect shading, soiling, or a failing string in real time.
- Track cumulative PV energy yield over weeks and months to validate system performance against the original design estimate.
- Alert on a sudden drop in one or more string power values to identify panel faults before they affect overall yield.
- Report daily and monthly PV generation totals from the energy register for tenant billing or feed-in tariff reconciliation.
Installation
Enable Modbus TCP on the Alpha ESS Storion SMILE by navigating to the communication or Modbus section of the inverter's local configuration menu and confirming the slave ID is set to 85 and port is 502.
Connect the inverter's Ethernet port to the same LAN segment as the ModbusCloud Gateway using a standard RJ45 cable, and assign the inverter a static IP address to prevent connection drops after DHCP renewals.
In the ModbusCloud portal, add a new device, import the Alpha ESS Storion SMILE (pv) template, and enter the inverter's static IP address, port 502, and unit ID 85.
Spot-check the connection by confirming that register power_a (address 161) returns a non-zero value during daylight hours, and that each active string (power_b through power_g) reports a plausible watt reading.
Things to watch for
Port 502 is refused even though the inverter is reachable on the network. Why?
Modbus TCP must be explicitly enabled on the Alpha ESS Storion SMILE. Access the inverter's local configuration interface, locate the communication or Modbus settings section, and activate the Modbus server. Some firmware versions require a service password (default 1111) to unlock this setting. Confirm port 502 is open before re-testing.
All register values drop to zero or read garbage after a few minutes. What now?
Alpha ESS inverters allow only one active Modbus TCP client at a time. If another device such as a home energy manager or EV charger is also polling the inverter on port 502, the connection will be interrupted. Disconnect the competing client, or configure polling so only one device queries the inverter at any given moment.
The energy register at address 1086 shows an unexpectedly large number. Is the scaling wrong?
The Alpha ESS Modbus protocol stores some energy and power values as large integers that require a scaling factor applied by the reading application. Confirm that your ModbusCloud template is interpreting the uint32 value correctly. If the number appears implausibly high, cross-check the raw register value against the total yield shown in the Alpha ESS cloud app to determine the correct multiplier.
One or more PV string registers always return zero during daylight. Is the register wrong?
String power registers power_b through power_g correspond to individual MPPT or string inputs. If fewer than six strings are physically connected, unused inputs will read zero. Verify your system wiring matches the string numbering in the Alpha ESS installation manual, and confirm all active string inputs are seated and enabled in the inverter configuration.
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