Modbus Reference · Growatt
Growatt Modbus TCP registers
Register reference for reading Growatt MIN, MIC, MAX, and SPH inverters over Modbus TCP, including SPH battery and grid meter registers.
Connection parameters: Modbus TCP on port 502, function code FC04 (Read Input Registers) for inverter production; the grid-meter reader uses FC03. The default unit ID is 1.
Production registers (MIN / MIC / MAX)
| Function | Register(s) | Raw format | Scaling | Metric | App output |
|---|---|---|---|---|---|
| FC04 | 11–12 | U32 BE | × 0.1 W | Instantaneous inverter power | Whole Watts |
| FC04 | 28–29 | U32 BE | × 0.1 kWh | Lifetime energy production | Wh (raw × 100) |
| FC04 | 35 | U16 | × 0.1 V | AC output voltage, Vgrid R-phase | Volts |
Battery registers (SPH)
| Register(s) | Raw format | Scaling | Metric |
|---|---|---|---|
| 101 | U16 | × 0.1 V | Battery voltage |
| 102 | U16 | × 1% | State of charge |
| 104–105 | U32 BE | × 0.1 W | Battery power |
Growatt battery power is treated as an unsigned absolute value; no charge/discharge sign conversion is applied.
Grid meter registers
| Register(s) | Raw format | Scaling | Metric | Word order |
|---|---|---|---|---|
| 30024–30025 | I32 | × 0.1 W | Instantaneous grid power | Big-endian |
| 30026–30027 | U32 | × 0.1 kWh | Cumulative exported energy | Little-endian |
| 30028–30029 | U32 | × 0.1 kWh | Cumulative imported energy | Little-endian |
Note the mixed word order in the Growatt meter block: power is big-endian while the energy counters are little-endian.
Sign conventions used throughout: grid power is normalized so positive = exporting and negative = importing. Battery power is normalized so charging and discharging follow the app's convention noted per table.
Growatt's standard ShineWiFi/ShineLAN sticks are cloud-only; local Modbus TCP typically requires an RS485-to-TCP gateway wired to the inverter's RS485/SYS-COM port.
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