Deye, Sunsynk and Growatt Hybrid Inverter Modbus Registers

Register maps for the hybrid inverters people most often wire to their own monitoring: Deye (and Sunsynk, which uses Deye's map) and Growatt. They look alike — RS485, 9600 baud, battery and grid values — but they disagree on almost every detail that matters: function code, 32-bit word order, signs, even which map applies to which model. This page gives the registers for each and the differences side by side.

Which Map Applies?

Connection

Deye Single-Phase Hybrid (Sunsynk) Registers

Holding registers, read with FC03, addresses as written (no offset). 32-bit values: the first register is the low word.

Deye Three-Phase Hybrid Registers

Also FC03 holding registers. The high-voltage (HV) models use different scales from the low-voltage (LV) ones for battery voltage and power, and the 32-bit power values keep their high word in a separate block (687–709).

Registers 553–554 hold the warning words and 555–558 the fault words. Some HV firmware versions changed scale factors; check a known value before trusting a scale.

Growatt Registers

Measurements are input registers, read with FC04 — FC03 at the same numbers returns settings. Every register is unsigned 16-bit; 32-bit values are high word first. Import and export, charge and discharge are separate unsigned registers, not one signed value.

SPH / SPA storage inverters

MIN TL-XH / MOD TL3-XH

Signs and Directions

• Deye grid power (169, 625): positive = buying from the grid, negative = selling — stated in Deye's document.
• Deye battery power (190, 590): the document only says signed. In the field it reads positive while discharging and negative while charging; check it once against a known charge before building logic on it.
• Growatt: no signed power values — import, export, charge and discharge each have their own register.

Writing Settings

Common Mistakes

• Growatt measurements read with FC03: you get settings. Use FC04.
• Word order mixed up: Deye is low word first, Growatt high word first. Totals come out absurd when you swap them.
• Deye total grid import from 78–79: the high word is at 80; 79 is the grid frequency.
• Temperatures 100 °C too high: Deye adds 1000 to temperatures — subtract it before dividing by 10.
• Single-phase registers on a three-phase Deye (or the reverse): check register 0 first.
• HV battery values off by 10: HV three-phase models use 0.1 V and 10 W where LV models use 0.01 V and 1 W.
• Timeouts: a Growatt needs about a second between requests; a Deye behind a cheap gateway may need requests of 20 registers or fewer.
• Polling through the logger port: the Solarman/Shine logger is not a Modbus TCP server.

Step-by-Step: Reading a Hybrid with ModbusManager

1 Connect — Modbus RTU on a USB-RS485 adapter (9600 8N1, slave ID 1), or Modbus TCP to an RS485-to-Ethernet gateway.

2 Poll windows — Deye: FC03 at 59 (39 registers), 108 (5), 150 (45). Growatt: FC04 at the blocks of your family, with an interval of a second or more.

3 Scaled tags (Pro) — register tags with the right type and word order (little for Deye, big for Growatt) and Scale / Offset from the tables. A Deye temperature becomes Scale 0.1, Offset −100 — that is (raw − 1000) ÷ 10.

4 Derived values — a line of Structured Text adds PV1 and PV2, or splits Deye's signed grid power into import and export for a chart.

Download a Ready-Made Workspace

• Three FC03 windows for a Deye single-phase hybrid (59–97, 108–112, 150–194)
• 24 register tags with low-word-first order, scales and the temperature offset already set — PV, battery, grid, load, energy counters, run state
• A short script for total PV power and import/export
• A dashboard: PV gauge, run-state lamp, load, grid and battery power, battery SOC, today's energy and a power-flow trend

Frequently Asked Questions

Does Sunsynk use the same Modbus registers as Deye?

In practice, yes: Sunsynk inverters are built by Deye and the community integrations read them with Deye's map. Sunsynk has not published its own register document, so confirm a few values (SOC, grid power) on your unit.

Can I read a Deye over Modbus TCP?

Not directly. The inverter speaks Modbus RTU on RS485; the Wi-Fi logger's port 8899 uses Solarman's own protocol. Put an RS485-to-Ethernet gateway on the RS485 port to get Modbus TCP.

Why does my Growatt return settings instead of measurements?

You are reading holding registers (FC03). Growatt measurements are input registers: use FC04.

Why is the Deye battery temperature 120 °C?

Deye adds 1000 to temperatures. Subtract 1000 and divide by 10: a raw 1215 is 21.5 °C.

Is Deye battery power positive when charging or discharging?

Deye's document only says the value is signed. In practice it is positive while discharging and negative while charging; confirm it once on your system.

Sources

Deye, Modbus RTU Protocol V118 (single-phase hybrids; last revision entry 2021-04-08), and Deye's three-phase energy-storage Modbus RTU protocol (revision entries 2020–2025); Growatt, Growatt Inverter Modbus RTU Protocol V1.24. These are manufacturer documents, but none of the copies used is hosted on the manufacturer's own website: they came from a Deye distributor and from public integration projects. Sunsynk has not published a register document of its own. Ask your distributor for the issue that matches your model and firmware, and check a few known values before relying on a register.